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Sample records for soluble tryptic peptides

  1. Increased [32P]-phosphorylation of tryptic peptides of erythrocyte spectrin in Duchenne muscular dystrophy

    International Nuclear Information System (INIS)

    Mabry, M.E.; Roses, A.D.

    1981-01-01

    Increased [32P]-incorporation in tryptic peptides of the erythrocyte membrane protein spectrin Band 2 in Duchenne muscular dystrophy (DMD) was studied in a consecutive series of 10 matched DMD/control pairs. Spectrin was [32P]-phosphorylated by cyclic AMP-independent endogenous membrane protein kinase in the presence of [gamma-32P]ATP. [32P]-labeled spectrin was isolated, purified, and subjected to tryptic cleavage with excess trypsin. The resulting peptides were separated on a high-resolution 5%/15% stacking SDS--polyacrylamide gel electrophoresis system. Liquid scintillation counting was performed on sequential slices of unstained gels. A broad [32P]-labeled band containing a number of [32P]-polypeptides was found to be more highly [32P]-phosphorylated in DMD patients than in their matched controls. This band migrated with an apparent molecular mass of 4.8-5.2 kilodaltons and contained approximately 55% of total [32P] radioactivity covalently bound to spectrin peptides. These data demonstrated an increased [32P]-phosphorylation of an identifiable tryptic peptide fraction in DMD that is consistent with previous reports of increased spectrin Band 2 [32P]-phosphorylation in DMD

  2. Increased (/sup 32/P)-phosphorylation of tryptic peptides of erythrocyte spectrin in Duchenne muscular dystrophy

    Energy Technology Data Exchange (ETDEWEB)

    Mabry, M.E.; Roses, A.D.

    Increased (32P)-incorporation in tryptic peptides of the erythrocyte membrane protein spectrin Band 2 in Duchenne muscular dystrophy (DMD) was studied in a consecutive series of 10 matched DMD/control pairs. Spectrin was (32P)-phosphorylated by cyclic AMP-independent endogenous membrane protein kinase in the presence of (gamma-32P)ATP. (32P)-labeled spectrin was isolated, purified, and subjected to tryptic cleavage with excess trypsin. The resulting peptides were separated on a high-resolution 5%/15% stacking SDS--polyacrylamide gel electrophoresis system. Liquid scintillation counting was performed on sequential slices of unstained gels. A broad (32P)-labeled band containing a number of (32P)-polypeptides was found to be more highly (32P)-phosphorylated in DMD patients than in their matched controls. This band migrated with an apparent molecular mass of 4.8-5.2 kilodaltons and contained approximately 55% of total (32P) radioactivity covalently bound to spectrin peptides. These data demonstrated an increased (32P)-phosphorylation of an identifiable tryptic peptide fraction in DMD that is consistent with previous reports of increased spectrin Band 2 (32P)-phosphorylation in DMD.

  3. Peptides derived from tryptic hydrolysate of Bacillus subtilis culture suppress fungal spoilage of table grapes.

    Science.gov (United States)

    Zhang, Bo; Wang, Jingnan; Ning, Shuqing; Yuan, Quan; Chen, Xiangning; Zhang, Yanyan; Fan, Junfeng

    2018-01-15

    This study confirmed the anti-fungal effect of trypsin-treated Bacillus subtilis culture (BC) (tryptic hydrolysate, TH) on mold growth on Kyoho grapes. We examined the anti-fungal activity of TH by identifying TH peptides and performing a computational docking analysis. TH was more potent than untreated BC in suppressing fungal growth on grapes. Specifically, TH maintained grape freshness by inhibiting respiration and rachis browning, maintaining firmness, and preventing weight loss. Thirty-six inhibitory peptides against β-1,3-glucan synthase (GS) were screened from 126 TH peptides identified through proteomic analysis. Among them, 13 peptides bound tightly to GS active pockets with lower binding energies than that of GppNHp. The most potent peptides, LFEIDEELNEK and FATSDLNDLYR, were synthesized, and further experiments showed that these peptides had a highly suppressive effect on GS activity and Aspergillus niger and Penicillium chrysogenum growth. Our results confirm that tryptic treatment is effective for improving the anti-fungal activity of BC. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Identification of Alternative Splice Variants Using Unique Tryptic Peptide Sequences for Database Searches.

    Science.gov (United States)

    Tran, Trung T; Bollineni, Ravi C; Strozynski, Margarita; Koehler, Christian J; Thiede, Bernd

    2017-07-07

    Alternative splicing is a mechanism in eukaryotes by which different forms of mRNAs are generated from the same gene. Identification of alternative splice variants requires the identification of peptides specific for alternative splice forms. For this purpose, we generated a human database that contains only unique tryptic peptides specific for alternative splice forms from Swiss-Prot entries. Using this database allows an easy access to splice variant-specific peptide sequences that match to MS data. Furthermore, we combined this database without alternative splice variant-1-specific peptides with human Swiss-Prot. This combined database can be used as a general database for searching of LC-MS data. LC-MS data derived from in-solution digests of two different cell lines (LNCaP, HeLa) and phosphoproteomics studies were analyzed using these two databases. Several nonalternative splice variant-1-specific peptides were found in both cell lines, and some of them seemed to be cell-line-specific. Control and apoptotic phosphoproteomes from Jurkat T cells revealed several nonalternative splice variant-1-specific peptides, and some of them showed clear quantitative differences between the two states.

  5. MALDI-based identification of stable hazelnut protein derived tryptic marker peptides.

    Science.gov (United States)

    Cucu, T; De Meulenaer, B; Devreese, B

    2012-01-01

    Food allergy is an important health problem especially in industrialised countries. Tree nuts, among which are hazelnuts (Corylus avellana), are typically causing serious and life-threatening symptoms in sensitive subjects. Hazelnut is used as a food ingredient in pastry, confectionary products, ice cream and meat products, therefore undeclared hazelnut can be often present as a cross-contaminant representing a threat for allergic consumers. Mass spectrometric techniques are used for the detection of food allergens in processed foods, but limited information regarding stable tryptic peptide markers for hazelnut is available. The aim of this study was to detect stable peptide markers from modified hazelnut protein through the Maillard reaction and oxidation in a buffered solution. Peptides ³⁹⁵Gly-Arg⁴⁰³ from Cor a 11 and ²⁰⁹Gln-Arg²¹⁷, ³⁵¹Ile-Arg³⁶³, ⁴⁶⁴Ala-Arg⁴⁷⁸ and ⁴⁰¹Val-Arg⁴¹⁷ from Cor a 9 hazelnut allergens proved to be the most stable and could be detected and confirmed with high scores in most of the modified samples. The identified peptides can be further used as analytical targets for the development of more robust quantitative methods for hazelnut detection in processed foods.

  6. Processed Meat Protein and Heat-Stable Peptide Marker Identification Using Microwave-Assisted Tryptic Digestion

    Directory of Open Access Journals (Sweden)

    Magdalena Montowska

    2016-01-01

    Full Text Available New approaches to rapid examination of proteins and peptides in complex food matrices are of great interest to the community of food scientists. The aim of the study is to examine the influence of microwave irradiation on the acceleration of enzymatic cleavage and enzymatic digestion of denatured proteins in cooked meat of five species (cattle, horse, pig, chicken and turkey and processed meat products (coarsely minced, smoked, cooked and semi-dried sausages. Severe protein aggregation occurred not only in heated meat under harsh treatment at 190 °C but also in processed meat products. All the protein aggregates were thoroughly hydrolyzed aft er 1 h of trypsin treatment with short exposure times of 40 and 20 s to microwave irradiation at 138 and 303 W. There were much more missed cleavage sites observed in all microwave-assisted digestions. Despite the incompleteness of microwave-assisted digestion, six unique peptide markers were detected, which allowed unambiguous identification of processed meat derived from the examined species. Although the microwave-assisted tryptic digestion can serve as a tool for rapid and high-throughput protein identification, great caution and pre-evaluation of individual samples is recommended in protein quantitation.

  7. Physicochemical properties determining the detection probability of tryptic peptides in Fourier transform mass spectrometry. A correlation study

    DEFF Research Database (Denmark)

    Nielsen, Michael L; Savitski, Mikhail M; Kjeldsen, Frank

    2004-01-01

    Sequence verification and mapping of posttranslational modifications require nearly 100% sequence coverage in the "bottom-up" protein analysis. Even in favorable cases, routine liquid chromatography-mass spectrometry detects from protein digests peptides covering 50-90% of the sequence. Here we...... investigated the reasons for limited peptide detection, considering various physicochemical aspects of peptide behavior in liquid chromatography-Fourier transform mass spectrometry (LC-FTMS). No overall correlation was found between the detection probability and peptide mass. In agreement with literature data...... between pI and signal response. An explanation of this paradoxal behavior was found through the observation that more acidic tryptic peptide lengths tend to be longer. Longer peptides tend to acquire higher average charge state in positive mode electrospray ionization than more basic but shorter...

  8. Discordance between in silico & in vitro analyses of ACE inhibitory & antioxidative peptides from mixed milk tryptic whey protein hydrolysate.

    Science.gov (United States)

    Chatterjee, Alok; Kanawjia, S K; Khetra, Yogesh; Saini, Prerna

    2015-09-01

    ACE inhibitory and antioxidative peptides identified by LCMS/MS, from mixed milk (Bubalus bubalis and Bos taurus) tryptic whey protein hydrolysate, were compared with the in silico predictions. α la and ß lg sequences, both from Bubalus bubalis and Bos taurus, were used for in silico study. SWISS-PROT and BIOPEP protein libraries were accessed for prediction of peptide generation. Study observed gaps in the prediction versus actual results, which remain unaddressed in the literature. Many peptides obtained in vitro, were not reflected in in silico predictions. Differences in identified peptides in separate libraries were observed too. In in silico prediction, peptides with known biological activities were also not reflected. Predictions, towards generation of bioactive peptides, based upon in silico release of proteins and amino acid sequences from different sources and thereupon validation in relation to actual results has often been reported in research literature. Given that computer aided simulation for prediction purposes is an effective research direction, regular updating of protein libraries and an effectual integration, for more precise results, is critical. The gaps addressed between these two techniques of research, have not found any address in literature. Inclusion of more flexibility with the variables, within the tools being used for prediction, and a hierarchy based database with search options for various peptides, will further enhance the scope and strength of research.

  9. Characterisation of tryptic peptides of phosphorylated tyrosine hydroxylase by high-pressure liquid chromatography electrospray ionisation mass spectrometry

    International Nuclear Information System (INIS)

    Graham, Mark E.; Dickson, Phillip W.; Dunkley, Peter R.; Nagy-Felsobuki, Ellak I. von

    2005-01-01

    Tyrosine hydroxylase (TH) is involved in the biosynthesis of catecholamines and is activated by phosphorylation. Phosphorylated TH was analysed using high-pressure liquid chromatography combined with electrospray mass spectrometry (HPLC ESI-MS). Two mass scanning methods were used to detect tryptic cleavage products of TH. In the positive electrospray ionisation mode (ESI+), the peptides that contain the phosphorylation sites of TH were identified. In the alternative method, a phosphopeptide was detected in the negative electrospray ionisation mode (ESI-) using single ion monitoring in combination with a sequential ESI+ switching experiment. A raised baseline interfered with detection of hydrophilic peptides in ESI-, with the signal-to-noise ratio indicating that the method was operating near the limit of detection for a conventional electrospray source. The switching method improved the certainty of identification of phosphopeptides

  10. Facilitating protein solubility by use of peptide extensions

    Science.gov (United States)

    Freimuth, Paul I; Zhang, Yian-Biao; Howitt, Jason

    2013-09-17

    Expression vectors for expression of a protein or polypeptide of interest as a fusion product composed of the protein or polypeptide of interest fused at one terminus to a solubility enhancing peptide extension are provided. Sequences encoding the peptide extensions are provided. The invention further comprises antibodies which bind specifically to one or more of the solubility enhancing peptide extensions.

  11. Determination of bovine lactoferrin in dairy products by ultra-high performance liquid chromatography–tandem mass spectrometry based on tryptic signature peptides employing an isotope-labeled winged peptide as internal standard

    International Nuclear Information System (INIS)

    Zhang, Jingshun; Lai, Shiyun; Cai, Zengxuan; Chen, Qi; Huang, Baifen; Ren, Yiping

    2014-01-01

    Highlights: • A UHPLC–MS/MS method for quantification of bovine lactoferrin was developed. • Tryptic fragment LRPVAAEIYGTK was chosen as signature peptide of bovine lactoferrin. • A winged peptide containing isotopically-labeled signature peptide was designed as internal standard. • The method for determining lactoferrin does not discriminate between the different forms of lactoferrin. • Meet the growing demand to quantify bovine lactoferrin in different dairy products. - Abstract: A new and sensitive determination method was developed for bovine lactoferrin in dairy products including infant formulas based on the signature peptide by ultra high-performance liquid chromatography and triple-quadrupole tandem mass spectrometry under the multiple reaction monitoring mode. The simple pretreatment procedures included the addition of a winged peptide containing the isotope-labeled signature peptide as internal standard, followed by an enzymatic digestion with trypsin. The signature peptide was chosen and identified from the tryptic hydrolyzates of bovine lactoferrin by ultra high-performance liquid chromatography and quadrupole-time-of-flight tandem mass spectrometry based on sequence database search. Analytes were separated on an ACQUITY UPLC BEH 300 C18 column and monitored by MS/MS in seven minutes. Quantitative result bias due to matrix effect and tryptic efficiency was corrected through the use of synthetic isotope-labeled standards. The limit of detection and limit of quantification were 0.3 mg/100 g and 1.0 mg/100 g, respectively. Bovine lactoferrin within the concentration range of 10–1000 nmol L −1 showed a strong linear relationship with a linear correlation coefficient (r) of >0.998. The intra- and inter-day precision of the method were RSD < 6.5% and RSD < 7.1%, respectively. Excellent repeatability (RSD < 6.4%) substantially supported the application of this method for the determination of bovine lactoferrin in dairy samples. The present

  12. Determination of bovine lactoferrin in dairy products by ultra-high performance liquid chromatography–tandem mass spectrometry based on tryptic signature peptides employing an isotope-labeled winged peptide as internal standard

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jingshun [Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051 (China); Lai, Shiyun [Beingmate Research Institute, Beingmate Baby and Child Food Co., Ltd., Hangzhou 310007 (China); Cai, Zengxuan [Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051 (China); Chen, Qi [Beingmate Research Institute, Beingmate Baby and Child Food Co., Ltd., Hangzhou 310007 (China); Huang, Baifen [Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051 (China); Ren, Yiping, E-mail: renyiping@263.net [Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051 (China)

    2014-06-01

    Highlights: • A UHPLC–MS/MS method for quantification of bovine lactoferrin was developed. • Tryptic fragment LRPVAAEIYGTK was chosen as signature peptide of bovine lactoferrin. • A winged peptide containing isotopically-labeled signature peptide was designed as internal standard. • The method for determining lactoferrin does not discriminate between the different forms of lactoferrin. • Meet the growing demand to quantify bovine lactoferrin in different dairy products. Abstract: A new and sensitive determination method was developed for bovine lactoferrin in dairy products including infant formulas based on the signature peptide by ultra high-performance liquid chromatography and triple-quadrupole tandem mass spectrometry under the multiple reaction monitoring mode. The simple pretreatment procedures included the addition of a winged peptide containing the isotope-labeled signature peptide as internal standard, followed by an enzymatic digestion with trypsin. The signature peptide was chosen and identified from the tryptic hydrolyzates of bovine lactoferrin by ultra high-performance liquid chromatography and quadrupole-time-of-flight tandem mass spectrometry based on sequence database search. Analytes were separated on an ACQUITY UPLC BEH 300 C18 column and monitored by MS/MS in seven minutes. Quantitative result bias due to matrix effect and tryptic efficiency was corrected through the use of synthetic isotope-labeled standards. The limit of detection and limit of quantification were 0.3 mg/100 g and 1.0 mg/100 g, respectively. Bovine lactoferrin within the concentration range of 10–1000 nmol L⁻¹ showed a strong linear relationship with a linear correlation coefficient (r) of >0.998. The intra- and inter-day precision of the method were RSD < 6.5% and RSD < 7.1%, respectively. Excellent repeatability (RSD < 6.4%) substantially supported the application of this method for the determination of bovine lactoferrin in dairy samples. The present method

  13. Fouling prevention of peptides from a tryptic whey hydrolysate during electromembrane processes by use of monovalent ion permselective membranes

    OpenAIRE

    Persico, Mathieu; Bazinet, Laurent

    2017-01-01

    Peptide adsorption occurring on conventional anion- and cation-exchange membranes is one of the main technological locks in electrodialysis (ED) for hydrolysate demineralization. Hence, the peptide fouling of monovalent anion (MAP) and monovalent cation (MCP) permselective membranes was studied and compared to conventional membranes (AMX-SB and CMX-SB). It appeared that the main peptide sequences responsible for fouling were TPEVDDEALEKFDK, VAGTWY and VLVLDTDYK for both anionic membranes; and...

  14. Soluble elastin peptides in cardiovascular homeostasis: Foe or ally.

    Science.gov (United States)

    Qin, Zhenyu

    2015-05-01

    Elastin peptides, also known as elastin-derived peptides or elastokines, are soluble polypeptides in blood and tissue. The blood levels of elastin peptides are usually low but can increase during cardiovascular diseases, such as atherosclerosis, aortic aneurysm and diabetes with vascular complications. Generally, elastin peptides are derived from the degradation of insoluble elastic polymers. The biological activities of elastin peptides are bidirectional, e.g., a pro-inflammatory effect on monocyte migration induction vs. a protective effect on vasodilation promotion. However, recent in vivo studies have demonstrated that elastin peptides promote the formation of atherosclerotic plaques in hypercholesterolemic mice and induce hyperglycemia and elevations in plasma lipid levels in fasted mice. More important, the detrimental effects induced by elastin peptides can be largely inhibited by genetic or pharmacological blockade of the elastin receptor complex or by neutralization of an antibody against elastin peptides. These studies indicate new therapeutic strategies for the treatment of cardiovascular diseases by targeting elastin peptide metabolism. Therefore, the goal of this review is to summarize current knowledge about elastin peptides relevant to cardiovascular pathologies to further delineate their potential application in cardiovascular disease. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Tandem mass spectrometry of human tryptic blood peptides calculated by a statistical algorithm and captured by a relational database with exploration by a general statistical analysis system.

    Science.gov (United States)

    Bowden, Peter; Beavis, Ron; Marshall, John

    2009-11-02

    A goodness of fit test may be used to assign tandem mass spectra of peptides to amino acid sequences and to directly calculate the expected probability of mis-identification. The product of the peptide expectation values directly yields the probability that the parent protein has been mis-identified. A relational database could capture the mass spectral data, the best fit results, and permit subsequent calculations by a general statistical analysis system. The many files of the Hupo blood protein data correlated by X!TANDEM against the proteins of ENSEMBL were collected into a relational database. A redundant set of 247,077 proteins and peptides were correlated by X!TANDEM, and that was collapsed to a set of 34,956 peptides from 13,379 distinct proteins. About 6875 distinct proteins were only represented by a single distinct peptide, 2866 proteins showed 2 distinct peptides, and 3454 proteins showed at least three distinct peptides by X!TANDEM. More than 99% of the peptides were associated with proteins that had cumulative expectation values, i.e. probability of false positive identification, of one in one hundred or less. The distribution of peptides per protein from X!TANDEM was significantly different than those expected from random assignment of peptides.

  16. Phosphotyrosine biased enrichment of tryptic peptides from cancer cells by combining pY-MIP and TiO2 affinity resins

    DEFF Research Database (Denmark)

    Bllaci, Loreta; Torsetnes, Silje Bøen; Wierzbicka, Celina Katarzyna

    2017-01-01

    Protein phosphorylation at distinct tyrosine residues (pY) is essential for fast, specific and accurate signal transduction in cells. Enrichment of pY-containing peptides derived from phosphoproteins is commonly facilitated by use of immobilized anti-pY antibodies prior to phosphoproteomics analy...

  17. Sequence of the radioactive tryptic peptide obtained after inactivating the F1-ATPase of the thermophilic bacterium PS3 with 5'-p-fluorosulfonylbenzoyl[3H]adenosine at 65 degrees C

    International Nuclear Information System (INIS)

    Bullough, D.A.; Yoshida, M.; Allison, W.S.

    1986-01-01

    Following a lag of about 30 min, the F1-ATPase from the thermophilic bacterium, PS3 (TF1), was inactivated slowly by 0.8 mM 5'-p-fluorosulfonylbenzoyladenosine (FSBA) at 23 degrees C and pH 7.0. When the enzyme was treated with 0.2 mM FSBA at pH 7.0 and 23 degrees C for 15 min and gel-filtered, no enzyme activity was lost. However, the lag in inactivation was abolished when the enzyme was subsequently incubated with 2.0 mM FSBA at 23 degrees C in the pH range from 6.8 to 10.0. The pH-inactivation profile obtained under these conditions revealed a pK alpha of about 9.3 which was associated with the inactivation. When pretreated TF1 was inactivated at 23 degrees C with [3H]FSBA by about 90%, greater than 20 mol of [3H]SBA was incorporated per mole of enzyme. TF1 was inactivated rapidly by 0.8 mM FSBA at pH 6.4 and 65 degrees C, and no lag was observed. Following inactivation of TF1 with 0.8 mM [3H]FSBA at 65 degrees C and pH 6.4, about 10 mol of [3H]SBA was incorporated per mole of enzyme. When a tryptic digest of the labeled enzyme was fractionated by reversed-phase high-performance liquid chromatography, a single major radioactive peptide was isolated. When subjected to automatic Edman degradation, this peptide was shown to have the amino acid sequence: A-L-A-P-E-I-V-G-E-E-H-X-Q-V-A-R, where X indicates that a phenylthiohydantoin derivative was not detected in cycle 12. However, from the DNA sequence of the gene encoding the subunit of TF1 (Y. Kagawa, M. Ishizuka, T. Saishu, and S. Nakao (1985)), this position has been shown to be occupied by tyrosine. This tyrosine is homologous with beta-Tyr-368 of the bovine mitochondrial F1-ATPase (MF1) the modification of which is responsible for the inactivation MF1 by FSBA

  18. Synthesis of water-soluble scaffolds for peptide cyclization, labeling, and ligation

    NARCIS (Netherlands)

    Smeenk, L.E.J.; Dailly, N.; Hiemstra, H.; van Maarseveen, J.H.; Timmerman, P.

    2012-01-01

    The synthesis and applications of water-soluble scaffolds that conformationally constrain side chain unprotected linear peptides containing two cysteines are described. These scaffolds contain a functionality with orthogonal reactivity to be used for labeling and ligation. This is illustrated by the

  19. PEPTIDE SOLUBILITY, STRUCTURE AND CHARGE POSITION EFFECT ON ADSORPTION BY ALUMINIUM HYDROXIDE

    Directory of Open Access Journals (Sweden)

    Mary Trujillo

    2008-04-01

    Full Text Available Solubility, structure and position of charges in a peptide antigen sequence can be mentioned as being amongst the basic features of adsorption. In order to study their effect on adsorption, seven analogue series were synthesized from a MSP-1 peptide sequence by systematically replacing each one of the positions in the peptide sequence by aspartic acid, glutamic acid, serine, alanine, asparagine, glutamine or lysine. Such modifications in analogue peptide sequences showed a non-regular tendency regarding solubility and adsorption data. Aspartic acid and Glutamic acid analogue series showed great improvements in adsorption, especially in peptides where Lysine in position 6 and Arginine in position 13 were replaced. Solubility of position 5 analogue was greater than the position 6 analogue in Aspartic acid series; however, the position 6 analogue showed best adsorption results whilst the Aspartic acid in position 5 analogue showed no adsorption in the same conditions. Nuclear Magnetic Resonance structural analysis revealed differences in the -helical structureextension between these analogues. The Aspartic acid in position 6, located in the polar side of the helix, may allow this analogueto fit better onto the adsorption regions suggesting that the local electrostatic charge is responsible for this behavior.

  20. Tryptic mapping and membrane topology of the benzodiazepine receptor alpha-subunit

    Energy Technology Data Exchange (ETDEWEB)

    Lentes, K.U.; Venter, J.C.

    1986-05-01

    Rat brain membrane benzodiazepine receptors (BZR) were photoaffinity labelled specifically (in presence or absence of 6 ..mu..M clonazepam) with 10 nM /sup 3/H-flunitrazepam (FNZ). Digestion of the FNZ-labelled, membrane-bound BZR with 200 ..mu..g trypsin/mg membrane protein yielded H/sub 2/O-soluble BZR-fragments of molecular mass (M/sub r/) 34, 31, 28, 24, 21, 18, 16, 12, 10 and 7kDa. Because the 34kDa-peptide is the largest fragment containing a FNZ-binding site they conclude that this represents the extracellular domain of the BZR. In the remaining pellet two labelled peptides with M/sub r/ of 44kDa and 28kDa were found that required the use of detergents for their solubilization; they therefore contain the membrane anchoring domain. Digestion of the 0.5% Na-deoxycholate solubilized, intact BZR (M/sub r/ 51kDa) resulted in the same tryptic pattern as the membrane form of the receptor plus two larger fragments of M/sub r/ 45kDa and 40kDa. Arrangement of all tryptic fragments with reference to the FNZ binding site reveals a membrane topology of the BZR alpha-subunit with 67% (34kDa) for the extracellular domain, 21% (11kDa) for the membrane anchoring domain and 12% (6kDa) for a putative cytoplasmic domain. The overlap between some of the labelled fragments suggest that the BZ binding site must be located near the membrane surface of the extracellular domain.

  1. A Novel Soluble Peptide with pH-Responsive Membrane Insertion.

    Science.gov (United States)

    Nguyen, Vanessa P; Alves, Daiane S; Scott, Haden L; Davis, Forrest L; Barrera, Francisco N

    2015-11-03

    Several diseases, such as cancer, are characterized by acidification of the extracellular environment. Acidosis can be employed as a target to specifically direct therapies to the diseased tissue. We have used first principles to design an acidity-triggered rational membrane (ATRAM) peptide with high solubility in solution that is able to interact with lipid membranes in a pH-dependent fashion. Biophysical studies show that the ATRAM peptide binds to the surface of lipid membranes at pH 8.0. However, acidification leads to the peptide inserting into the lipid bilayer as a transmembrane α-helix. The insertion of ATRAM into membranes occurs at a moderately acidic pH (with a pK of 6.5), similar to the extracellular pH found in solid tumors. Studies with human cell lines showed a highly efficient pH-dependent membrane targeting, without causing toxicity. Here we show that it is possible to rationally design a soluble peptide that selectively targets cell membranes in acidic environments.

  2. PROPRIEDADES EMULSIFICANTES E SOLUBILIDADE DA CASEÍNA BOVINA E DE SEUS HIDROLISADOS TRÍPTICOS: 1. EFEITO DO PH E DO TEMPO DE HIDRÓLISE EMULSIFYING PROPERTIES AND SOLUBILITY OF CASEIN AND IT’S TRYPTIC HYDROLYSATES: 1. EFFECTS OF PH AND HYDROLYSIS TIME

    Directory of Open Access Journals (Sweden)

    Ângela Jardim DUARTE

    1998-08-01

    Full Text Available Visando a aplicação industrial da caseína e de seus hidrolisados trípticos, foram estudados os efeitos da variação do pH e do tempo de hidrólise sobre suas características de solubilidade e propriedades emulsificantes. Testou-se os valores de pH de 3,0; 4,0; 5,0; 6,0; 7,0 e 8,0 e os tempos de hidrólise: 5, 10 15, 30 e 60min. Foram medidos a solubilidade, a capacidade emulsificante, o índice de atividade emulsificante, a estabilidade da emulsão, e calculdado o tamanho dos glóbulos de gordura. Os resultados obtidos para a caseína nativa indicaram que os melhores valores para estas propriedades funcionais foram encontrados em pH acima de 5,0. A hidrólise tríptica da caseína foi benéfica para sua solubilidade e capacidade emulsificante e prejudicou sua estabilidade, em todos os valores de pH e tempos de hidrólise, exceto no pH 5,0 com 5 min de reação. Por outro lado, este tratamento enzimático contribuiu para melhorar o índice de atividade emulsificante da caseína, entre valores de pH 3,0 e 5,0 e após 10 min de reação.The effects of pH and hydrolysis time on the solubility and emulsifying properties were studied, in view of the industrial application of casein and its tryptic hydrolyzates. It has been tested the pH values of 3,0; 4,0; 5,0; 6,0; 7,0 and 8,0 and the reaction times: 5, 10, 15, 30 and 60 min. It has been evaluated the solubility, the emulsifying capacity, the emulsifying activity index and the emulsion stability. The results show that the best values for the functional properties of native casein were achieved at pH above 5,0. The tryptic hydrolysis of casein favored the solubility and emulsifying capacity but reduced the emulsion stability, at all pH and hydrolysis times, except in pH 5,0 with 5min of reaction. Otherwise, this enzymatic treatment improved the emulsifying activity index of casein only between pH 3,0- 5,0, after 10 min of reaction.

  3. DEGRADATION AND DEBITTERING OF A TRYPTIC DIGEST FROM BETA-CASEIN BY AMINOPEPTIDASE-N FROM LACTOCOCCUS-LACTIS SUBSP CREMORIS WG2

    NARCIS (Netherlands)

    TAN, PST; VANKESSEL, TAJM; VANDEVEERDONK, FLM; ZUURENDONK, PF; BRUINS, AP; KONINGS, WN

    The mode of action of purified aminopeptidase N from Lactococcus lactis subsp. cremoris Wg2 on a complex peptide mixture of a tryptic digest from bovine beta-casein was analyzed. The oligopeptides produced in the tryptic digest before and after aminopeptidase N treatment were identified by analysis

  4. Stereochemistry Balances Cell Permeability and Solubility in the Naturally Derived Phepropeptin Cyclic Peptides.

    Science.gov (United States)

    Schwochert, Joshua; Lao, Yongtong; Pye, Cameron R; Naylor, Matthew R; Desai, Prashant V; Gonzalez Valcarcel, Isabel C; Barrett, Jaclyn A; Sawada, Geri; Blanco, Maria-Jesus; Lokey, R Scott

    2016-08-11

    Cyclic peptide (CP) natural products provide useful model systems for mapping "beyond-Rule-of-5" (bRo5) space. We identified the phepropeptins as natural product CPs with potential cell permeability. Synthesis of the phepropeptins and epimeric analogues revealed much more rapid cellular permeability for the natural stereochemical pattern. Despite being more cell permeable, the natural compounds exhibited similar aqueous solubility as the corresponding epimers, a phenomenon explained by solvent-dependent conformational flexibility among the natural compounds. When analyzing the polarity of the solution structures we found that neither the number of hydrogen bonds nor the total polar surface area accurately represents the solvation energies of the high and low dielectric conformations. This work adds to a growing number of natural CPs whose solvent-dependent conformational behavior allows for a balance between aqueous solubility and cell permeability, highlighting structural flexibility as an important consideration in the design of molecules in bRo5 chemical space.

  5. Small surfactant-like peptides can drive soluble proteins into active aggregates

    Directory of Open Access Journals (Sweden)

    Zhou Bihong

    2012-01-01

    Full Text Available Abstract Background Inactive protein inclusion bodies occur commonly in Escherichia coli (E. coli cells expressing heterologous proteins. Previously several independent groups have found that active protein aggregates or pseudo inclusion bodies can be induced by a fusion partner such as a cellulose binding domain from Clostridium cellulovorans (CBDclos when expressed in E. coli. More recently we further showed that a short amphipathic helical octadecapeptide 18A (EWLKAFYEKVLEKLKELF and a short beta structure peptide ELK16 (LELELKLKLELELKLK have a similar property. Results In this work, we explored a third type of peptides, surfactant-like peptides, for performing such a "pulling-down" function. One or more of three such peptides (L6KD, L6K2, DKL6 were fused to the carboxyl termini of model proteins including Aspergillus fumigatus amadoriase II (AMA, all three peptides were used, Bacillus subtilis lipase A (LipA, only L6KD was used, hereinafter the same, Bacillus pumilus xylosidase (XynB, and green fluorescent protein (GFP, and expressed in E. coli. All fusions were found to predominantly accumulate in the insoluble fractions, with specific activities ranging from 25% to 92% of the native counterparts. Transmission electron microscopic (TEM and confocal fluorescence microscopic analyses confirmed the formation of protein aggregates in the cell. Furthermore, binding assays with amyloid-specific dyes (thioflavin T and Cong red to the AMA-L6KD aggregate and the TEM analysis of the aggregate following digestion with protease K suggested that the AMA-L6KD aggregate may contain structures reminiscent of amyloids, including a fibril-like structure core. Conclusions This study shows that the surfactant-like peptides L6KD and it derivatives can act as a pull-down handler for converting soluble proteins into active aggregates, much like 18A and ELK16. These peptide-mediated protein aggregations might have important implications for protein aggregation in

  6. Rheostatic control of tryptic digestion in a microscale fluidic system

    International Nuclear Information System (INIS)

    Percy, Andrew J.; Schriemer, David C.

    2010-01-01

    Integrated fluidic systems that unite bottom-up and top-down proteomic approaches have the potential to deliver complete protein characterization. To circumvent fraction collection, as is conducted in current blended approaches, a technique to regulate digestion efficiency in a flow-through system is required. The present study examined the concept of regulating tryptic digestion in an immobilized enzyme reactor (IMER), incorporating mixed solvent systems for digestion acceleration. Using ovalbumin, cytochrome c, and myoglobin as protein standards, we demonstrate that tryptic digestion can be efficiently regulated between complete digestion and no digestion extremes by oscillating between 45 and 0% acetonitrile in the fluid stream. Solvent composition was tuned using programmable solvent waveforms in a closed system consisting of the IMER, a sample delivery stream, a dual gradient pumping system and a mass spectrometer. Operation in this rheostatic digestion mode provides access to novel peptide mass maps (due to substrate unfolding hysteresis) as well as the intact protein, in a reproducible and stable fashion. Although cycle times were on the order of 90 s for testing purposes, we show that regulated digestion is sufficiently rapid to be limited by solvent switching efficiency and kinetics of substrate unfolding/folding. Thus, regulated digestion should be useful in blending bottom-up and top-down proteomics in a single closed fluidic system.

  7. One-pot synthesis of water soluble iron nanoparticles using rationally-designed peptides and ligand release.

    Science.gov (United States)

    Papst, Stefanie; Cheong, Soshan; Banholzer, Moritz J; Brimble, Margaret A; Williams, David E; Tilley, Richard D

    2013-05-18

    Herein we report the rational design of new phosphopeptides for control of nucleation, growth and aggregation of water-soluble, superparamagnetic iron-iron oxide core-shell nanoparticles. The use of the designed peptides enables a one-pot synthesis that avoids utilizing unstable or toxic iron precursors, organic solvents, and the need for exchange of capping agent after synthesis of the NPs.

  8. Association of MiR-126 with Soluble Mesothelin-Related Peptides, a Marker for Malignant Mesothelioma

    Czech Academy of Sciences Publication Activity Database

    Santarelli, L.; Strafella, E.; Staffolani, S.; Amati, M.; Emanuelli, M.; Sartini, D.; Pozzi, V.; Carbonari, D.; Bracci, M.; Pignotti, E.; Mazzanti, P.; Sabbatini, A.; Ranaldi, R.; Gasparini, S.; Neužil, Jiří; Tomasetti, M.

    2011-01-01

    Roč. 6, č. 4 (2011), e18232 E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GA204/08/0811 Institutional research plan: CEZ:AV0Z50520701 Keywords : Malignant pleural mesothelioma * microRNAs * soluble mesothelin-related peptides Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.092, year: 2011

  9. Limited tryptic proteolysis of the benzodiazepine binding proteins in different species reveals structural homologies.

    Science.gov (United States)

    Friedl, W; Lentes, K U; Schmitz, E; Propping, P; Hebebrand, J

    1988-12-01

    Peptide mapping can be used to elucidate further the structural similarities of the benzodiazepine binding proteins in different vertebrate species. Crude synaptic membrane preparations were photoaffinity-labeled with [3H]flunitrazepam and subsequently degraded with various concentrations of trypsin. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by fluorography allowed a comparison of the molecular weights of photolabeled peptides in different species. Tryptic degradation led to a common peptide of 40K in all species investigated, a finding indicating that the benzodiazepine binding proteins are structurally homologous in higher bony fishes and tetrapods.

  10. Soluble N-Ethylmaleimide-Sensitive Factor Attachment Protein Receptor-Derived Peptides for Regulation of Mast Cell Degranulation.

    Science.gov (United States)

    Yang, Yoosoo; Kong, Byoungjae; Jung, Younghoon; Park, Joon-Bum; Oh, Jung-Mi; Hwang, Jaesung; Cho, Jae Youl; Kweon, Dae-Hyuk

    2018-01-01

    Vesicle-associated V-soluble N -ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins and target membrane-associated T-SNAREs (syntaxin 4 and SNAP-23) assemble into a core trans -SNARE complex that mediates membrane fusion during mast cell degranulation. This complex plays pivotal roles at various stages of exocytosis from the initial priming step to fusion pore opening and expansion, finally resulting in the release of the vesicle contents. In this study, peptides with the sequences of various SNARE motifs were investigated for their potential inhibitory effects against SNARE complex formation and mast cell degranulation. The peptides with the sequences of the N-terminal regions of vesicle-associated membrane protein 2 (VAMP2) and VAMP8 were found to reduce mast cell degranulation by inhibiting SNARE complex formation. The fusion of protein transduction domains to the N-terminal of each peptide enabled the internalization of the fusion peptides into the cells equally as efficiently as cell permeabilization by streptolysin-O without any loss of their inhibitory activities. Distinct subsets of mast cell granules could be selectively regulated by the N-terminal-mimicking peptides derived from VAMP2 and VAMP8, and they effectively decreased the symptoms of atopic dermatitis in mouse models. These results suggest that the cell membrane fusion machinery may represent a therapeutic target for atopic dermatitis.

  11. Short communication: Tryptic β-casein hydrolysate modulates enteric nervous system development in primary culture.

    Science.gov (United States)

    Cossais, F; Clawin-Rädecker, I; Lorenzen, P C; Klempt, M

    2017-05-01

    The intestinal tract of the newborn is particularly sensitive to gastrointestinal disorders, such as infantile diarrhea or necrotizing colitis. Perinatal development of the gut also encompasses the maturation of the enteric nervous system (ENS), a main regulator of intestinal motility and barrier functions. It was recently shown that ENS maturation can be enhanced by nutritional factors to improve intestinal maturation. Bioactivity of milk proteins is often latent, requiring the release of bioactive peptides from inactive native proteins. Several casein-derived hydrolysates presenting immunomodulatory properties have been described recently. Furthermore, accumulating data indicate that milk-derived hydrolysate can enhance gut maturation and enrichment of milk formula with such hydrolysates has recently been proposed. However, the capability of milk-derived bioactive hydrolysate to target ENS maturation has not been analyzed so far. We, therefore, investigated the potential of a recently described tryptic β-casein hydrolysate to modulate ENS growth parameters in an in vitro model of rat primary culture of ENS. Rat primary cultures of ENS were incubated with a bioactive tryptic β-casein hydrolysate and compared with untreated controls or to cultures treated with native β-casein or a Prolyve β-casein hydrolysate (Lyven, Colombelles, France). Differentiation of enteric neurons and enteric glial cells, and establishment of enteric neural network were analyzed using immunohistochemistry and quantitative PCR. Effect of tryptic β-casein hydrolysate on bone morphogenetic proteins (BMP)/Smad pathway, an essential regulator of ENS development, was further assessed using quantitative PCR and immunochemistry. Tryptic β-casein hydrolysate stimulated neurite outgrowth and simultaneously modulated the formation of enteric ganglia-like structures, whereas native β-casein or Prolyve β-casein hydrolysate did not. Additionally, treatment with tryptic bioactive

  12. Enrichment and desalting of tryptic protein digests and the protein depletion using boron nitride

    Energy Technology Data Exchange (ETDEWEB)

    Fischnaller, Martin; Köck, Rainer; Bakry, Rania, E-mail: rania.bakry@uibk.ac.at; Bonn, Günther K.

    2014-05-01

    Highlights: • Protein tryptic digests were desalted and enriched utilizing hexagonal boron nitride. • Phosphopeptides were desalted with high recovery rates. • Boron nitride exhibits high wettability allowing fast sample preparation. • Boron nitride shows protein depletion capability applied for peptide purification. - Abstract: Sample preparation still remains a great challenge in modern bioanalysis and the interest in new efficient solid phase extraction (SPE) materials still remains high. In this work, hexagonal boron nitride (h-BN) is introduced as a new SPE material for the isolation and enrichment of peptides. The h-BN is isoelectronic and structurally similar to graphite. It has remarkable properties including good thermal conductivity, excellent thermal and chemical stability and a better oxidation resistance than graphite. BN attracts increasing interest because of its wide range of applicability. In the present work, the great potential of h-BN, as a new SPE-material, on the enrichment, preconcentration and desalting of tryptic digest of model proteins is demonstrated. A special attention was dedicated to the efficient enrichment of hydrophilic phosphopeptides. Two elution protocols were developed for the enrichment of peptides compatible for subsequent MALDI-MS and ESI-MS analysis. In addition, the recoveries of 5 peptides and 3 phosphopeptides with wide range of pI values utilizing h-BN materials with different surface areas were investigated. 84–106% recovery rate could be achieved using h-BN materials. The results were compared with those obtained using graphite and silica C18 under the same elution conditions, and lower recoveries were obtained. In addition, h-BN was found to have a capability of protein depletion, which is requisite for the peptide profiling.

  13. Enrichment and desalting of tryptic protein digests and the protein depletion using boron nitride

    International Nuclear Information System (INIS)

    Fischnaller, Martin; Köck, Rainer; Bakry, Rania; Bonn, Günther K.

    2014-01-01

    Highlights: • Protein tryptic digests were desalted and enriched utilizing hexagonal boron nitride. • Phosphopeptides were desalted with high recovery rates. • Boron nitride exhibits high wettability allowing fast sample preparation. • Boron nitride shows protein depletion capability applied for peptide purification. - Abstract: Sample preparation still remains a great challenge in modern bioanalysis and the interest in new efficient solid phase extraction (SPE) materials still remains high. In this work, hexagonal boron nitride (h-BN) is introduced as a new SPE material for the isolation and enrichment of peptides. The h-BN is isoelectronic and structurally similar to graphite. It has remarkable properties including good thermal conductivity, excellent thermal and chemical stability and a better oxidation resistance than graphite. BN attracts increasing interest because of its wide range of applicability. In the present work, the great potential of h-BN, as a new SPE-material, on the enrichment, preconcentration and desalting of tryptic digest of model proteins is demonstrated. A special attention was dedicated to the efficient enrichment of hydrophilic phosphopeptides. Two elution protocols were developed for the enrichment of peptides compatible for subsequent MALDI-MS and ESI-MS analysis. In addition, the recoveries of 5 peptides and 3 phosphopeptides with wide range of pI values utilizing h-BN materials with different surface areas were investigated. 84–106% recovery rate could be achieved using h-BN materials. The results were compared with those obtained using graphite and silica C18 under the same elution conditions, and lower recoveries were obtained. In addition, h-BN was found to have a capability of protein depletion, which is requisite for the peptide profiling

  14. Caseinophosphopeptides released after tryptic hydrolysis versus simulated gastrointestinal digestion of a casein-derived by-product.

    Science.gov (United States)

    Cruz-Huerta, E; García-Nebot, M J; Miralles, B; Recio, I; Amigo, L

    2015-02-01

    The production of caseinophosphopeptides from a casein-derived by-product generated during the manufacture of a functional ingredient based on antihypertensive peptides was attempted. The casein by-product was submitted to tryptic hydrolysis for 30, 60 and 120min and further precipitated with calcium chloride and ethanol at pH 4.0, 6.0 and 8.0. Identification and semi quantification of the derived products by tandem mass spectrometry revealed some qualitative and quantitative changes in the released caseinophosphopeptides over time at the different precipitation pHs. The by-product was also subjected to simulated gastrointestinal digestion. Comparison of the resulting peptides showed large sequence homology in the phosphopeptides released by tryptic hydrolysis and simulated gastrointestinal digestion. Some regions, specifically αS1-CN 43-59, αS1-CN 60-74, β-CN 1-25 and β-CN 30-50 showed resistance to both tryptic hydrolysis and simulated digestion. The results of the present study suggest that this casein-derived by-product can be used as a source of CPPs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. The tryptic cleavage product of the mature form of the bovine desmoglein 1 ectodomain is one of the antigen moieties immunoprecipitated by all sera from symptomatic patients affected by a new variant of endemic pemphigus.

    Science.gov (United States)

    Abréu-Vélez, Ana María; Javier Patiño, Pablo; Montoya, Fernando; Bollag, Wendy B

    2003-01-01

    Multiple antigens are recognized by sera from patients with pemphigus foliaceus (PF). Several have been identified including keratin 59, desmocollins, envoplakin, periplakin, and desmogleins 1 and 3 (Dsg1 and Dsg3). In addition, an 80 kDa antigen was identified as the N-terminal fragment of Dsg1 using as antigen source an insoluble epidermal cell envelope preparation. However, still unsolved was the identity of the most important antigenic moiety, a 45 kDa tryptic fragment which is recognized by all sera from patients with fogo selvagem, pemphigus foliaceus, by half of pemphigus vulgaris sera and by a new variant of endemic pemphigus in E1 Bagre, Colombia that resembles Senear-Usher syndrome. Here, we report the identification of the 45 kDa conformational epitope of a soluble tryptic cleavage product from viable bovine epidermis. To elucidate the nature of this peptide, viable bovine epidermis was trypsin-digested, and glycosylated peptides were partially purified on a concanavalin A (Con-A) affinity column. This column fraction was then used as an antigen source for further immunoaffinity purification. A PF patient's serum covalently coupled to a Staphylococcus aureus protein A column was incubated with the Con-A eluted products and the immuno-isolated antigen was separated by SDS-PAGE, transferred to a membrane, and visualized with Coomassie blue, silver and amido black stains. The 45 kD band was subjected to amino acid sequence analysis revealing the sequence, EXIKFAAAXREGED, which matched the mature form of the extracellular domain of bovine Dsg1. This study confirms the biological importance of the ectodomain of Dsg1 as well as the relevance of conformational epitopes in various types of pemphigus.

  16. Soluble expression and purification of the recombinant bioactive peptide precursor BPP-1 in Escherichia coli using a cELP-SUMO dual fusion system.

    Science.gov (United States)

    Rao, Shengqi; Zang, Xiangyu; Yang, Zhenquan; Gao, Lu; Yin, Yongqi; Fang, Weiming

    2016-02-01

    A bioactive peptide precursor (BPP-1, 14.3 kDa/115AA), a newly designed polypeptide that may exert a potential antihypertensive effect in vivo, is composed of many different ACE inhibitory peptides and antioxidant peptides tandemly linked according to the restriction sites of gastrointestinal proteases. In this report, we present a novel method to obtain soluble BPP-1 in Escherichia coli using cationic elastin-like polypeptide and SUMO (cELP-SUMO) tags. The cELP-SUMO-tagged fusion protein was expressed in soluble form at 20 °C for 20 h. After purification based on the inverse transition cycling (ITC) method, the purified cELP-SUMO-CFPP fusion protein was subsequently cleaved by a SUMO protease to release the mature BPP-1. After a subsequent simple salt precipitation process, approximately 167.2 mg of recombinant BPP-1 was obtained from 1 l of bacterial culture with at least 92% purity. The molecular mass (Mr) of the recombinant BPP-1 was confirmed by MALDI-TOF MS to equal 14,347. The purified BPP-1 was subjected to simulated gastrointestinal digestion, and the resulting hydrolysates exhibited notable ACE inhibitory and antioxidant activities in vitro. This report provides the first description of the soluble production of a bioactive peptide multimer with potential ACE inhibitory and antioxidant activities in E. coli using a cELP-SUMO tag. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Rapid tryptic mapping using enzymatically active mass spectrometer probe tips

    Energy Technology Data Exchange (ETDEWEB)

    Dogruel, D.; Williams, P.; Nelson, R.W. [Arizona State Univ., Tempe, AZ (United States)

    1995-12-01

    A method has been developed for rapid, sensitive, and accurate tryptic mapping of polypeptides using matrix-assisted laser desorption/ionization time-of-flight mass analysis. The technique utilizes mass spectrometer probe tips which have been activated through the covalent immobilization of trypsin. The enzymatically active probe tips were used for the tryptic mapping of chicken egg lysozyme and the results compared with those obtained using either free trypsin or agarose-immobilized trypsin. A significant increase in the overall sensitivity of the process was observed using the active probe tips, as well as the production of more characteristic proteolytic fragments and the elimination of background signals due to the autolysis of the trypsin. Further, probe tip digestions were found to be rapid and convenient. 19 refs., 6 figs., 2 tabs.

  18. Real-time monitoring of peptic and tryptic digestions of bovine β-casein using quartz crystal microbalance

    International Nuclear Information System (INIS)

    Huenerbein, Andreas; Schmelzer, Christian E.H.; Neubert, Reinhard H.H.

    2007-01-01

    In this study peptic and tryptic digestions of bovine β-casein were investigated using quartz crystal microbalance (QCM). β-Casein, which was used as a model protein, was immobilized on the surface of the QCM sensor where its degradation caused shifts in the resonant frequency. Atomic force microscopy was applied for the characterization of the protein layer. Different pH-values for peptic or tryptic digestions were chosen to visualize their effect on enzyme activity. Lower frequency shifts were observed at pH-values deviating from those at the maximum enzyme activity. In the case of the peptic digestion the frequency shift at pH 4 was more than 10 times smaller than those at pH 2. The frequency shifts for tryptic digestions at pH 5.4 and pH 6.4 were about two thirds compared to that obtained for the digestion at pH 7.4. The identification of peptides using MALDI-ToF mass spectrometry was used for verification of the proteolyses of the immobilized protein. Furthermore, it was shown that the QCM technique allows close observation of the effect of different pH-values on the immobilized casein layer. All in all, QCM facilitates the monitoring of the progress of enzymatic reactions in real-time

  19. Real-time monitoring of peptic and tryptic digestions of bovine {beta}-casein using quartz crystal microbalance

    Energy Technology Data Exchange (ETDEWEB)

    Huenerbein, Andreas [Institute of Pharmaceutics and Biopharmaceutics, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120 Halle (Saale) (Germany)]. E-mail: andreas.huenerbein@pharmazie.uni-halle.de; Schmelzer, Christian E.H. [Institute of Pharmaceutics and Biopharmaceutics, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120 Halle (Saale) (Germany); Neubert, Reinhard H.H. [Institute of Pharmaceutics and Biopharmaceutics, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120 Halle (Saale) (Germany)

    2007-02-12

    In this study peptic and tryptic digestions of bovine {beta}-casein were investigated using quartz crystal microbalance (QCM). {beta}-Casein, which was used as a model protein, was immobilized on the surface of the QCM sensor where its degradation caused shifts in the resonant frequency. Atomic force microscopy was applied for the characterization of the protein layer. Different pH-values for peptic or tryptic digestions were chosen to visualize their effect on enzyme activity. Lower frequency shifts were observed at pH-values deviating from those at the maximum enzyme activity. In the case of the peptic digestion the frequency shift at pH 4 was more than 10 times smaller than those at pH 2. The frequency shifts for tryptic digestions at pH 5.4 and pH 6.4 were about two thirds compared to that obtained for the digestion at pH 7.4. The identification of peptides using MALDI-ToF mass spectrometry was used for verification of the proteolyses of the immobilized protein. Furthermore, it was shown that the QCM technique allows close observation of the effect of different pH-values on the immobilized casein layer. All in all, QCM facilitates the monitoring of the progress of enzymatic reactions in real-time.

  20. Milk peptides increase iron solubility in water but do not affect DMT-1 expression in Caco-2 cells

    Science.gov (United States)

    In vitro digestion of milk produces peptide fractions that enhance iron uptake by Caco-2 cells. Our objectives were to investigate whether these fractions a) exert their effect by increasing relative gene expression of DMT-1 in Caco-2 cells b) enhance iron dialyzability when added in meals. Peptid...

  1. Interpretation of Tandem Mass Spectrometry (MSMS) Spectra for Peptide Analysis

    DEFF Research Database (Denmark)

    Hjernø, Karin; Højrup, Peter

    2015-01-01

    The aim of this chapter is to give a short introduction to peptide analysis by mass spectrometry (MS) and interpretation of fragment mass spectra. Through examples and guidelines we demonstrate how to understand and validate search results and how to perform de novo sequencing based on the often...... very complex fragmentation pattern obtained by tandem mass spectrometry (also referred to as MSMS). The focus is on simple rules for interpretation of MSMS spectra of tryptic as well as non-tryptic peptides....

  2. Peptide separation by capillary electrophoresis with ultraviolet detection: Some simple approaches to enhance detection sensitivity and resolution

    International Nuclear Information System (INIS)

    Surugau, Noumie L.

    2011-01-01

    Capillary electrophoresis (CE) is one of the leading separation technologies for analysis of water-soluble analytes. CE has many advantages over the more established methods such as liquid chromatography and gel electrophoresis particularly in rapid analysis, require very little sample, use less or no toxic organic solvent, high peak efficiency and ease of automation. Despite the many attractive advantages of CE, CE users continue to seek improvements particularly on detection sensitivity, resolution and selectivity. This paper presented several simple approaches to improve detection sensitivity using simple sample pre-concentration called field-enhanced sample injection (FESI) and chromatographic-based ZipTip C 18 pre-concentrator. Also, some improvements in the resolution of complex peptides mixture when using two strategies namely, capillary coating and manipulation of the hydrophobicity of peptides using perfluorinated acids as background electrolyte (BGE), which have anionic conjugate base forms with hydrophobic character. As test compounds, standard peptide mixture and proteins digests were used for these studies. The results showed that FESI has significantly enhanced the detection signal of peptide standards and bovine serum albumin (BSA) tryptic digests. As for the use of ZipTip C 18 pre-concentrator, selective enhancement in detection signal was particularly notable on the late migrating peptides. Coating the capillary proved to have little changes on the CE of peptides when used in conjunction with acidic BGE. Electropherograms of BSA tryptic peptides in pentafluoropropionic acid (PFPA) and heptafluorobutyric acid (HFBA) showed interesting profile, with notable resolution improvement for peptides with close similarity in electrophoretic mobilities. (author)

  3. Supercritical fluid chromatographic resolution of water soluble isomeric carboxyl/amine terminated peptides facilitated via mobile phase water and ion pair formation.

    Science.gov (United States)

    Patel, M A; Riley, F; Ashraf-Khorassani, M; Taylor, L T

    2012-04-13

    Both analytical scale and preparative scale packed column supercritical fluid chromatography (SFC) have found widespread applicability for chiral separations of multiple polar pharmaceutical candidates. However, SFC is rapidly becoming an achiral technique. More specifically, ion pair SFC is finding greater utility for separation of ionic analytes such as amine salts and organic sulfonates. The key to this success is, in part, the incorporation of additives such as trifluoroacetic acid and ammonium acetate into the mobile phase in association with a wide variety of both bonded silica stationary phases and high purity bare silica. Ion pairing SFC coupled with evaporative light scattering detection and mass spectrometric detection is presented here for the separation of water soluble, uncapped, isomeric peptide pairs that differ in amino acid arrangement. The separation is best achieved on either diol-bonded silica or bare silica with 1-5% (w/w) water as a significant ingredient in the mobile phase. Nitrogenous stationary phases such as 2-ethylpyridine, which had been very successful for the separation of capped peptides failed to yield the desired separation regardless of the mobile phase composition. A HILIC type retention mechanism is postulated for the separation of both isomeric uncapped peptide pairs. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. pH-sensitive polymeric nanoparticles to improve oral bioavailability of peptide/protein drugs and poorly water-soluble drugs.

    Science.gov (United States)

    Wang, Xue-Qing; Zhang, Qiang

    2012-10-01

    pH-sensitive polymeric nanoparticles are promising for oral drug delivery, especially for peptide/protein drugs and poorly water-soluble medicines. This review describes current status of pH-sensitive polymeric nanoparticles for oral drug delivery and introduces the mechanisms of drug release from them as well as possible reasons for absorption improvement, with emphasis on our contribution to this field. pH-sensitive polymeric nanoparticles are prepared mainly with polyanions, polycations, their mixtures or cross-linked polymers. The mechanisms of drug release are the result of carriers' dissolution, swelling or both of them at specific pH. The possible reasons for improvement of oral bioavailability include the following: improve drug stability, enhance mucoadhesion, prolong resident time in GI tract, ameliorate intestinal permeability and increase saturation solubility and dissolution rate for poorly water-soluble drugs. As for the advantages of pH-sensitive nanoparticles over conventional nanoparticles, we conclude that (1) most carriers used are enteric-coating materials and their safety has been approved. (2) The rapid dissolution or swelling of carriers at specific pH results in quick drug release and high drug concentration gradient, which is helpful for absorption. (3) At the specific pH carriers dissolve or swell, and the bioadhesion of carriers to mucosa becomes high because nanoparticles turn from solid to gel, which can facilitate drug absorption. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Efficient expression of a soluble lipid transfer protein (LTP) of Platanus orientalis using short peptide tags and structural comparison with the natural form.

    Science.gov (United States)

    Salari, Farhad; Vahedi, Fatemeh; Chamani, Jamshidkhan; Varasteh, Abdolreza; Ketabdar, Hanieh; Sankian, Mojtaba

    2015-01-01

    Successful recombinant allergen-based immunotherapy has drawn a great deal of attention to use recombinant allergens for new therapeutic and/or diagnostic strategies. The Escherichia coli expression system is frequently used to produce recombinant allergens; however, protein expression in E. coli often results in inclusion bodies. Here, we focused on the expression of two recombinant soluble forms of Pla or 3 using solubility-enhancing peptide tags, human immune deficiency virus type 1 transactivator of transcription core domain and poly-arginine-lysine: rTAT-Pla or 3 and rPoly-Arg-Lys-Pla or 3. Structural characteristics and IgE reactivity of purified recombinant proteins were compared with natural Pla or 3 (nPla or 3) isolated from Platanus orientalis using circular dichroism spectra, fluorescence spectroscopy, and immunoblotting. Likewise, intrinsic viscosity and Stokes radius of the natural and recombinant Pla or 3 allergens were determined to analyze structural compactness in aqueous media. The results indicate high-level solubility and efficient expression of the fusion proteins (rTAT-Pla or 3 and rPoly-Arg-Lys-Pla or 3) compared with the wild-type recombinant. Furthermore, the similar structural characteristics and IgE-binding activities of the fusion proteins to nPla or 3 provide a promising tool for allergy diagnosis and treatment. © 2014 International Union of Biochemistry and Molecular Biology, Inc.

  6. The microtubule-associated protein 1A (MAP1A) is an early molecular target of soluble Aβ-peptide

    DEFF Research Database (Denmark)

    Clemmensen, C; Aznar, S; Knudsen, G M

    2012-01-01

    that microtubule rearrangements may be proximate to neuritic degeneration and deficits in episodic declarative memory. Here, we examined primary cortical neurons for changes in markers associated with synaptic function following exposure to sublethal concentrations of non-aggregated Aβ-peptide. This data show...

  7. A water soluble Cu(I)-NHC for CuAAC ligation of unprotected peptides under open air conditions.

    Science.gov (United States)

    Gaulier, Christelle; Hospital, Audrey; Legeret, Bertrand; Delmas, Agnès F; Aucagne, Vincent; Cisnetti, Federico; Gautier, Arnaud

    2012-04-25

    A reducing agent-free version of CuAAC able to operate under open air conditions is reported. A readily-synthesizable, hydrophilic and highly stable Cu(I)-NHC allows the clean ligations of unprotected peptides comprising sensitive side chains, at millimolar concentrations.

  8. Capillary sieving electrophoresis and micellar electrokinetic capillary chromatography produce highly correlated separation of tryptic digests

    Science.gov (United States)

    Dickerson, Jane A.; Dovichi, Norman J.

    2011-01-01

    We perform two-dimensional capillary electrophoresis on fluorescently labeled proteins and peptides. Capillary sieving electrophoresis was performed in the first dimension and micellar electrokinetic capillary chromatography was performed in the second. A cellular homogenate was labeled with the fluorogenic reagent FQ and separated using the system. This homogenate generated a pair of ridges; the first had essentially constant migration time in the CSE dimension, while the second had essentially constant migration time in the MEKC dimension. In addition a few spots were scattered through the electropherogram. The same homogenate was digested using trypsin, and then labeled and subjected to the two dimensional separation. In this case, the two ridges observed from the original two-dimensional separation disappeared, and were replaced by a set of spots that fell along the diagonal. Those spots were identified using a local-maximum algorithm and each was fit using a two-dimensional Gaussian surface by an unsupervised nonlinear least squares regression algorithm. The migration times of the tryptic digest components were highly correlated (r = 0.862). When the slowest migrating components were eliminated from the analysis, the correlation coefficient improved to r = 0.956. PMID:20564272

  9. Analysis and Evaluation of the Inhibitory Mechanism of a Novel Angiotensin-I-Converting Enzyme Inhibitory Peptide Derived from Casein Hydrolysate.

    Science.gov (United States)

    Tu, Maolin; Liu, Hanxiong; Zhang, Ruyi; Chen, Hui; Mao, Fengjiao; Cheng, Shuzhen; Lu, Weihong; Du, Ming

    2018-04-25

    Casein hydrolysates exert various biological activities, and the responsible functional peptides are being identified from them continuously. In this study, the tryptic casein hydrolysate was fractionated by an ultrafiltration membrane (3 kDa), and the peptides were identified by capillary electrophoresis-quadrupole-time-of-flight-tandem mass spectrometry. Meanwhile, in silico methods were used to analyze the toxicity, solubility, stability, and affinity between the peptides and angiotensin-I-converting enzyme (ACE). Finally, a new angiotensin-I-converting enzyme inhibitory (ACEI) peptide, EKVNELSK, derived from α s1 -casein (fragment 35-42) was screened. The half maximal inhibitory concentration value of the peptide is 5.998 mM, which was determined by a high-performance liquid chromatography method. The Lineweaver-Burk plot indicated that this peptide is a mixed-type inhibitor against ACE. Moreover, Discovery Studio 2017 R2 software was adopted to perform molecular docking to propose the potential mechanisms underlying the ACEI activity of the peptide. These results indicated that EKVNELSK is a new ACEI peptide identified from casein hydrolysate.

  10. Bile salts-containing vesicles: promising pharmaceutical carriers for oral delivery of poorly water-soluble drugs and peptide/protein-based therapeutics or vaccines.

    Science.gov (United States)

    Aburahma, Mona Hassan

    2016-07-01

    Most of the new drugs, biological therapeutics (proteins/peptides) and vaccines have poor performance after oral administration due to poor solubility or degradation in the gastrointestinal tract (GIT). Though, vesicular carriers exemplified by liposomes or niosomes can protect the entrapped agent to a certain extent from degradation. Nevertheless, the harsh GIT environment exemplified by low pH, presence of bile salts and enzymes limits their capabilities by destabilizing them. In response to that, more resistant bile salts-containing vesicles (BS-vesicles) were developed by inclusion of bile salts into lipid bilayers constructs. The effectiveness of orally administrated BS-vesicles in improving the performance of vesicles has been demonstrated in researches. Yet, these attempts did not gain considerable attention. This is the first review that provides a comprehensive overview of utilizing BS-vesicles as a promising pharmaceutical carrier with a special focus on their successful applications in oral delivery of therapeutic macromolecules and vaccines. Insights on the possible mechanisms by which BS-vesicles improve the oral bioavailability of the encapsulated drug or immunological response of entrapped vaccine are explained. In addition, methods adopted to prepare and characterize BS-vesicles are described. Finally, the gap in the scientific researches tackling BS-vesicles that needs to be addressed is highlighted.

  11. Production and characterization of soluble human TNFRI-Fc and human HO-1(HMOX1) transgenic pigs by using the F2A peptide.

    Science.gov (United States)

    Park, Sol Ji; Cho, Bumrae; Koo, Ok Jae; Kim, Hwajung; Kang, Jung Taek; Hurh, Sunghoon; Kim, Su Jin; Yeom, Hye Jung; Moon, Joonho; Lee, Eun Mi; Choi, Ji Yei; Hong, Ju Ho; Jang, Goo; Hwang, Joing-Ik; Yang, Jaeseok; Lee, Byeong Chun; Ahn, Curie

    2014-06-01

    Generation of transgenic pigs for xenotransplantation is one of the most promising technologies for resolving organ shortages. Human heme oxygenase-1 (hHO-1/HMOX1) can protect transplanted organs by its strong anti-oxidative, anti-apoptotic, and anti-inflammatory effects. Soluble human TNFRI-Fc (shTNFRI-Fc) can inhibit the binding of human TNF-α (hTNF-α) to TNF receptors on porcine cells, and thereby, prevent hTNF-α-mediated inflammation and apoptosis. Herein, we successfully generated shTNFRI-Fc-F2A-HA-hHO-1 transgenic (TG) pigs expressing both shTNFRI-Fc and hemagglutinin-tagged-human heme oxygenase-1 (HA-hHO-1) by using an F2A self-cleaving peptide. shTNFRI-Fc and HA-hHO-1 transgenes containing the F2A peptide were constructed under the control of the CAG promoter. Transgene insertion and copy number in the genome of transgenic pigs was confirmed by polymerase chain reaction (PCR) and Southern blot analysis. Expressions of shTNFRI-Fc and HA-hHO-1 in TG pigs were confirmed using PCR, RT-PCR, western blot, ELISA, and immunohistochemistry. shTNFRI-Fc and HA-hHO-1 were expressed in various organs, including the heart, lung, and spleen. ELISA assays detected shTNFRI-Fc in the sera of TG pigs. For functional analysis, fibroblasts isolated from a shTNFRI-Fc-F2A-HA-hHO-1 TG pig (i.e., #14; 1 × 10(5) cells) were cultured with hTNF-α (20 ng/mL) and cycloheximide (10 μg/mL). The viability of shTNFRI-Fc-F2A-HA-hHO-1 TG pig fibroblasts was significantly higher than that of the wild type (wild type vs. shTNFRI-Fc-F2A-HA-hHO-1 TG at 24 h, 31.6 ± 3.2 vs. 60.4 ± 8.3 %, respectively; p hHO-1 TG pig fibroblasts was lower than that of the wild type pig fibroblasts (wild type vs. shTNFRI-Fc-F2A-HA-hHO-1 TG at 12 h, 812,452 ± 113,078 RLU vs. 88,240 ± 10,438 RLU, respectively; p hHO-1 TG pigs generated by the F2A self-cleaving peptide express both shTNFRI-Fc and HA-hHO-1 molecules, which provides protection against oxidative and inflammatory injury

  12. Optimizing the identification of citrullinated peptides by mass spectrometry

    DEFF Research Database (Denmark)

    Bennike, Tue; Lauridsen, Kasper B.; Olesen, Michael Kruse

    2013-01-01

    Citrullinated proteins have been associated with several diseases and citrullination can most likely function as a target for novel diagnostic agents and unravel disease etiologies. The correct identification of citrullinated proteins is therefore of most importance. Mass spectrometry (MS) driven...... of trypsin, digestion was performed on synthetic peptide sets containing either arginine or citrulline. The peptide sequences originated from disease-associated in vivo citrullinated proteins; some reported as being C-terminal tryptic citrullinated peptides. Furthermore, the proteolytic activity was verified...

  13. Antioxidant properties of a radical-scavenging peptide purified from enzymatically prepared fish skin gelatin hydrolysate.

    Science.gov (United States)

    Mendis, Eresha; Rajapakse, Niranjan; Kim, Se-Kwon

    2005-02-09

    Hoki (Johnius belengerii) skin gelatin was hydrolyzed with three commercial enzymes to identify radical-scavenging potencies of derived peptides. Peptides derived from tryptic hydrolysate exhibited the highest scavenging activities on superoxide, carbon-centered 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals assessed by ESR spectroscopy. Following consecutive chromatographic separations of tryptic hydroolysate, the peptide sequence His-Gly-Pro-Leu-Gly-Pro-Leu (797 Da) acted as a strong radical scavenger under studied conditions. Further, this peptide could act as an antioxidant against linoleic acid peroxidation and the activity was closer to the highly active synthetic antioxidant butylated hydroxytoluene (BHT). In addition, antioxidative enzyme levels in cultured human hepatoma cells were increased in the presence of this peptide and it was presumed to be the peptide involved in maintaining the redox balance in the cell environment. Present data indicate that free-radical-scavenging activities of hoki skin gelatin peptides substantially contribute to their antioxidant properties measured in different oxidative systems.

  14. Soluble γ-secretase modulators selectively inhibit the production of the 42-amino acid amyloid β peptide variant and augment the production of multiple carboxy-truncated amyloid β species.

    Science.gov (United States)

    Wagner, Steven L; Zhang, Can; Cheng, Soan; Nguyen, Phuong; Zhang, Xulun; Rynearson, Kevin D; Wang, Rong; Li, Yueming; Sisodia, Sangram S; Mobley, William C; Tanzi, Rudolph E

    2014-02-04

    Alzheimer's disease (AD) is characterized pathologically by an abundance of extracellular neuritic plaques composed primarily of the 42-amino acid amyloid β peptide variant (Aβ42). In the majority of familial AD (FAD) cases, e.g., those harboring mutations in presenilin 1 (PS1), there is a relative increase in the levels of Aβ42 compared to the levels of Aβ40. We previously reported the characterization of a series of aminothiazole-bridged aromates termed aryl aminothiazole γ-secretase modulators or AGSMs [Kounnas, M. Z., et al. (2010) Neuron 67, 769-780] and showed their potential for use in the treatment of FAD [Wagner, S. L., et al. (2012) Arch. Neurol. 69, 1255-1258]. Here we describe a series of GSMs with physicochemical properties improved compared to those of AGSMs. Specific heterocycle replacements of the phenyl rings in AGSMs provided potent molecules with improved aqueous solubilities. A number of these soluble γ-secretase modulators (SGSMs) potently lowered Aβ42 levels without inhibiting proteolysis of Notch or causing accumulation of amyloid precursor protein carboxy-terminal fragments, even at concentrations approximately 1000-fold greater than their IC50 values for reducing Aβ42 levels. The effects of one potent SGSM on Aβ peptide production were verified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry, showing enhanced production of a number of carboxy-truncated Aβ species. This SGSM also inhibited Aβ42 peptide production in a highly purified reconstituted γ-secretase in vitro assay system and retained the ability to modulate γ-secretase-mediated proteolysis in a stably transfected cell culture model overexpressing a human PS1 mutation validating the potential for use in FAD.

  15. Immunostimulatory property of a synthetic peptide belonging to the soluble ATP diphosphohydro-lase isoform (SmATPDase 2 and immunolocalisation of this protein in the Schistosoma mansoni egg

    Directory of Open Access Journals (Sweden)

    Rita Gabriela Pedrosa Ribeiro Mendes

    2011-11-01

    Full Text Available A peptide (SmB2LJ; r175-194 that belongs to a conserved domain from Schistosoma mansoni SmATPDase 2 and is shared with potato apyrase, as predicted by in silico analysis as antigenic, was synthesised and its immunostimulatory property was analysed. When inoculated in BALB/c mice, this peptide induced high levels of SmB2LJ-specific IgG1 and IgG2a subtypes, as detected by enzyme linked immunosorbent assay. In addition, dot blots were found to be positive for immune sera against potato apyrase and SmB2LJ. These results suggest that the conserved domain r175-194 from the S. mansoni SmATPDase 2 is antigenic. Western blots were performed and the anti-SmB2LJ antibody recognised in adult worm (soluble worm antigen preparation or soluble egg antigen antigenic preparations two bands of approximately 63 and 55 kDa, molecular masses similar to those predicted for adult worm SmATPDase 2. This finding strongly suggests the expression of this same isoform in S. mansoni eggs. To assess localisation of SmATPDase 2, confocal fluorescence microscopy was performed using cryostat sections of infected mouse liver and polyclonal antiserum against SmB2LJ. Positive reactions were identified on the external surface from the miracidium in von Lichtenberg's envelope and, in the outer side of the egg-shell, showing that this soluble isoform is secreted from the S. mansoni eggs.

  16. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds known as peptide nucleic acids, bind complementary DNA and RNA strands, and generally do so more strongly than the corresponding DNA or RNA strands while exhibiting increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from...

  17. High-level soluble expression of the functional peptide derived from the C-terminal domain of the sea cucumber lysozyme and analysis of its antimicrobial activity

    Directory of Open Access Journals (Sweden)

    Lina Cong

    2014-11-01

    Conclusion: These results indicate that the expressed rSjLys-C is a highly soluble product and has a strong antimicrobial activity. Therefore, gaining a large quantity of biologically active rSjLys-C will be used for further biochemical and structural studies and provide a potential use in aquaculture and medicine.

  18. Effect of Vericiguat, a Soluble Guanylate Cyclase Stimulator, on Natriuretic Peptide Levels in Patients With Worsening Chronic Heart Failure and Reduced Ejection Fraction

    DEFF Research Database (Denmark)

    Gheorghiade, Mihai; Greene, Stephen J; Butler, Javed

    2015-01-01

    IMPORTANCE: Worsening chronic heart failure (HF) is a major public health problem. OBJECTIVE: To determine the optimal dose and tolerability of vericiguat, a soluble guanylate cyclase stimulator, in patients with worsening chronic HF and reduced left ventricular ejection fraction (LVEF). DESIGN, ...

  19. Insulin rapidly stimulates phosphorylation of a 46-kDa membrane protein on tyrosine residues as well as phosphorylation of several soluble proteins in intact fat cells

    International Nuclear Information System (INIS)

    Haering, H.U.; White, M.F.; Machicao, F.; Ermel, B.; Schleicher, E.; Obermaier, B.

    1987-01-01

    It is speculated that the transmission of an insulin signal across the plasma membrane of cells occurs through activation of the tyrosine-specific receptor kinase, autophosphorylation of the receptor, and subsequent phosphorylation of unidentified substrates in the cell. In an attempt to identify possible substrates, the authors labeled intact rat fat cells with [ 32 P]orthophosphate and used an antiphosphotyrosine antibody to identify proteins that become phosphorylated on tyrosine residues in an insulin-stimulated way. In the membrane fraction of the fat cells, they found, in addition to the 95-kDa β-subunit of the receptor, a 46-kDa phosphoprotein that is phosphorylated exclusively on tyrosine residues. This protein is not immunoprecipitated by antibodies against different regions of the insulin receptor and its HPLC tryptic peptide map is different from the tryptic peptide map of the insulin receptor, suggesting that it is not derived from the receptor β-subunit. Insulin stimulates the tyrosine phosphorylation of the 46-kDa protein within 150 sec in the intact cell 3- to 4-fold in a dose-dependent way at insulin concentrations between 0.5 nM and 100 nM. Insulin (0.5 nM, 100 nM) stimulated within 2 min the 32 P incorporation into a 116-kDa band, a 62 kDa band, and three bands between 45 kDa and 50 kDa 2- to 10-fold. They suggest that the 46-kDa membrane protein and possibly also the soluble proteins are endogenous substrates of the receptor tyrosine kinase in fat cells and that their phosphorylation is an early step in insulin signal transmission

  20. Open tubular capillary column for the separation of cytochrome C tryptic digest in capillary electrochromatography.

    Science.gov (United States)

    Ali, Faiz; Cheong, Won Jo

    2015-10-01

    A silica capillary of 50 μm internal diameter and 500 mm length (416 mm effective length) was chemically modified with 4-(trifluoromethoxy) phenyl isocyanate in the presence of dibutyl tin dichloride as catalyst. Sodium diethyl dithiocarbamate was reacted with the terminal halogen of the bound ligand to incorporate the initiator moiety, and in situ polymerization was performed using a monomer mixture of styrene, N-phenylacrylamide, and methacrylic acid. The resultant open tubular capillary column immobilized with the copolymer layer was used for the separation of tryptic digest of cytochrome C in capillary electrochromatography. The sample was well eluted and separated into many components. The elution patterns of tryptic digest of cytochrome C were studied with respect to pH and water content in the mobile phase. This preliminary study demonstrates that open tubular capillary electrochromatography columns with a modified copolymer layer composed of proper nonpolar and polar units fabricated by reversible addition-fragmentation transfer polymerization can be useful as separation media for proteomic analysis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Stimulation of Interleukin-10 Production by Acidic β-Lactoglobulin-Derived Peptides Hydrolyzed with Lactobacillus paracasei NCC2461 Peptidases

    OpenAIRE

    Prioult, Guénolée; Pecquet, Sophie; Fliss, Ismail

    2004-01-01

    We have previously demonstrated that Lactobacillus paracasei NCC2461 may help to prevent cow's milk allergy in mice by inducing oral tolerance to β-lactoglobulin (BLG). To investigate the mechanisms involved in this beneficial effect, we examined the possibility that L. paracasei induces tolerance by hydrolyzing BLG-derived peptides and liberating peptides that stimulate interleukin-10 (IL-10) production. L. paracasei peptidases have been shown to hydrolyze tryptic-chymotryptic peptides from ...

  2. Hydrogen rearrangement to and from radical z fragments in electron capture dissociation of peptides

    DEFF Research Database (Denmark)

    Savitski, Mikhail M; Kjeldsen, Frank; Nielsen, Michael L

    2007-01-01

    Hydrogen rearrangement is an important process in radical chemistry. A high degree of H. rearrangement to and from z. ionic fragments (combined occurrence frequency 47% compared with that of z.) is confirmed in analysis of 15,000 tandem mass spectra of tryptic peptides obtained with electron...

  3. Identification of a Bacteria Using Phylogenetic Relationships Revealed by MS/MS Sequencing of Tryptic Peptides Derived From Cellular Proteins

    National Research Council Canada - National Science Library

    Dworzanski, J. P; Wick, H; Snyder, A. P; Deshpande, S. V; Chen, R; Li, L

    2004-01-01

    .... In addition four hundred bacterial genome-sequencing projects are in progress. These achievements provide new possibilities for reliable identification of bacteria on a molecular level by retrieving their genomic information...

  4. Reducing the cost of semi-automated in-gel tryptic digestion and GeLC sample preparation for high-throughput proteomics.

    Science.gov (United States)

    Ruelcke, Jayde E; Loo, Dorothy; Hill, Michelle M

    2016-10-21

    Peptide generation by trypsin digestion is typically the first step in mass spectrometry-based proteomics experiments, including 'bottom-up' discovery and targeted proteomics using multiple reaction monitoring. Manual tryptic digest and the subsequent clean-up steps can add variability even before the sample reaches the analytical platform. While specialized filter plates and tips have been designed for automated sample processing, the specialty reagents required may not be accessible or feasible due to their high cost. Here, we report a lower-cost semi-automated protocol for in-gel digestion and GeLC using standard 96-well microplates. Further cost savings were realized by re-using reagent tips with optimized sample ordering. To evaluate the methodology, we compared a simple mixture of 7 proteins and a complex cell-lysate sample. The results across three replicates showed that our semi-automated protocol had performance equal to or better than a manual in-gel digestion with respect to replicate variability and level of contamination. In this paper, we also provide the Agilent Bravo method file, which can be adapted to other liquid handlers. The simplicity, reproducibility, and cost-effectiveness of our semi-automated protocol make it ideal for routine in-gel and GeLC sample preparations, as well as high throughput processing of large clinical sample cohorts. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Influence of atrial fibrillation on plasma von willebrand factor, soluble E-selectin, and N-terminal pro B-type natriuretic peptide levels in systolic heart failure.

    Science.gov (United States)

    Freestone, Bethan; Gustafsson, Finn; Chong, Aun Yeong; Corell, Pernille; Kistorp, Caroline; Hildebrandt, Per; Lip, Gregory Y H

    2008-05-01

    Endothelial dysfunction is present in patients with heart failure (HF) due to left ventricular systolic dysfunction, as well as in patients with atrial fibrillation (AF) who have normal cardiac function. It is unknown whether AF influences the degree of endothelial dysfunction in patients with systolic HF. We measured levels of plasma von Willebrand factor (vWF) and E-selectin (as indexes of endothelial damage/dysfunction and endothelial activation, respectively; both enzyme-linked immunosorbent assay) in patients with AF and HF (AF-HF), who were compared to patients with sinus rhythm and HF (SR-HF), as well as in age-matched, healthy, control subjects. We also assessed the relationship of vWF and E-selectin to plasma N-terminal pro B-type natriuretic peptide (NTpro-BNP), a marker for HF severity and prognosis. One hundred ninety patients (73% men; mean age, 69.0 +/- 10.1 years [+/- SD]) with systolic HF were studied, who were compared to 117 healthy control subjects: 52 subjects (27%) were in AF, while 138 subjects (73%) were in sinus rhythm. AF-HF patients were older than SR-HF patients (p = 0.046), but left ventricular ejection fraction and New York Heart Association class were similar. There were significant differences in NT-proBNP (p NT-proBNP (p NT-proBNP levels (Spearman r = 0.139; p = 0.017). There is evidence of greater endothelial damage/dysfunction in AF-HF patients when compared to SR-HF patients. The clinical significance of this is unclear but may have prognostic value.

  6. Plutonium solubilities

    International Nuclear Information System (INIS)

    Puigdomnech, I.; Bruno, J.

    1991-02-01

    Thermochemical data has been selected for plutonium oxide, hydroxide, carbonate and phosphate equilibria. Equilibrium constants have been evaluated in the temperature range 0 to 300 degrees C at a pressure of 1 bar to T≤100 degrees C and at the steam saturated pressure at higher temperatures. Measured solubilities of plutonium that are reported in the literature for laboratory experiments have been collected. Solubility data on oxides, hydroxides, carbonates and phosphates have been selected. No solubility data were found at temperatures higher than 60 degrees C. The literature solubility data have been compared with plutonium solubilities calculated with the EQ3/6 geochemical modelling programs, using the selected thermodynamic data for plutonium. (authors)

  7. Properties of sweetened Indian yogurt (mishti dohi) as affected by added tryptic whey protein hydrolysate.

    Science.gov (United States)

    Chatterjee, Alok; Kanawjia, S K; Khetra, Yogesh

    2016-01-01

    Utilization of Indian sweetened yogurt (colloquially termed as Mishti Dohi), as vehicle for ACE inhibition and antioxidant activity, by added tryptic whey protein hydrolysate (TWPH) (@ 1, 2, 3 % v/milk), was attempted. Yogurt with 3 % TWPH exhibited non-significant (p > 0.05) difference for sensory attributes; but for body & texture; and maximum biofunctional properties, electing it for storage study (5 ± 1 °C). Flavor and body & texture scores registered significant (p antioxidant activity of control increased by 47.95 and 13.18 % and of experimental 24.58 and 13.43 %, correspondingly. Acidity rose to 1.18 % LA. Control samples conveyed 18.07 % and experimental of 20.77 % escalation for wheying-off. Tyrosine value was 27.04 μg.mL(-1). Among rheological attributes, firmness, quantified by texture analyzer TA-XT2i, dropped (p  0.05), throughout.

  8. On-target sample preparation of 4-sulfophenyl isothiocyanate-derivatized peptides using AnchorChip Targets

    DEFF Research Database (Denmark)

    Zhang, Xumin; Rogowska-Wrzesinska, Adelina; Roepstorff, Peter

    2008-01-01

    De novo sequencing of tryptic peptides by post source decay (PSD) or collision induced dissociation (CID) analysis using MALDI TOF-TOF instruments is due to the easy interpretation facilitated by the introduction of N-terminal sulfonated derivatives. Recently, a stable and cheap reagent, 4...

  9. Sequencing Lys-N Proteolytic Peptides by ESI and MALDI Tandem Mass Spectrometry

    Science.gov (United States)

    Dupré, Mathieu; Cantel, Sonia; Verdié, Pascal; Martinez, Jean; Enjalbal, Christine

    2011-02-01

    In this study, we explored the MS/MS behavior of various synthetic peptides that possess a lysine residue at the N-terminal position. These peptides were designed to mimic peptides produced upon proteolysis by the Lys-N enzyme, a metalloendopeptidase issued from a Japanese fungus Grifola frondosa that was recently investigated in proteomic studies as an alternative to trypsin digestion, as a specific cleavage at the amide X-Lys chain is obtained that provides N-terminal lysine peptide fragments. In contrast to tryptic peptides exhibiting a lysine or arginine residue solely at the C-terminal position, and are thus devoid of such basic amino acids within the sequence, these Lys-N proteolytic peptides can contain the highly basic arginine residue anywhere within the peptide chain. The fragmentation patterns of such sequences with the ESI-QqTOF and MALDI-TOF/TOF mass spectrometers commonly used in proteomic bottom-up experiments were investigated.

  10. Analysis of a Soluble (UreD:UreF:UreG)2 Accessory Protein Complex and its Interactions with Klebsiella aerogenes Urease by Mass Spectrometry

    Science.gov (United States)

    Farrugia, Mark A.; Han, Linjie; Zhong, Yueyang; Boer, Jodi L.; Ruotolo, Brandon T.; Hausinger, Robert P.

    2013-01-01

    Maturation of the nickel-containing urease of Klebsiella aerogenes is facilitated by the UreD, UreF, and UreG accessory proteins along with the UreE metallo-chaperone. A fusion of the maltose binding protein and UreD (MBP-UreD) was co-isolated with UreF and UreG in a soluble complex possessing a (MBP-UreD:UreF:UreG)2 quaternary structure. Within this complex a UreF:UreF interaction was identified by chemical cross-linking of the amino termini of its two UreF protomers, as shown by mass spectrometry of tryptic peptides. A pre-activation complex was formed by the interaction of (MBP-UreD:UreF:UreG)2 and urease. Mass spectrometry of intact protein species revealed a pathway for synthesis of the urease pre-activation complex in which individual hetero-trimer units of the (MBP-UreD:UreF:UreG)2 complex bind to urease. Together, these data provide important new insights into the structures of protein complexes associated with urease activation. PMID:23797863

  11. Competition between bound and free peptides in an ELISA-based procedure that assays peptides derived from protein digests

    Directory of Open Access Journals (Sweden)

    Pace Umberto

    2006-05-01

    Full Text Available Abstract Background We describe an ELISA-based method that can be used to identify and quantitate proteins in biological samples. In this method, peptides in solution, derived from proteolytic digests of the sample, compete with substrate-attached synthetic peptides for antibodies, also in solution, generated against the chosen peptides. The peptides used for the ELISA are chosen on the basis of their being (i products of the proteolytic (e.g. tryptic digestion of the protein to be identified and (ii unique to the target protein, as far as one can know from the published sequences. Results In this paper we describe the competition assay and we define the optimal conditions for the most effective assay. We have performed an analysis of the kinetics of interaction between the four components of the assay: the plastic substratum to which the peptide is bound, the bound peptide itself, the competing added peptide, and the antibody that is specific for the peptide and we compare the results of theoretical simulations to the actual data in some model systems. Conclusion The data suggest that the peptides bind to the plastic substratum in more than one conformation and that, once bound, the peptide displays different affinities for the antibody, depending on how it has bound to the plate

  12. Peptide sequencing and characterization of post-translational modifications by enhanced ion-charging and liquid chromatography electron-transfer dissociation tandem mass spectrometry

    DEFF Research Database (Denmark)

    Kjeldsen, Frank; Giessing, Anders; Ingrell, Christian R

    2007-01-01

    We have tested the effect of m-nitrobenzyl alcohol (m-NBA) as a method to increase the average charge state of protonated gas-phase molecular ions generated by ESI from tryptic peptides and phosphopeptides. Various concentrations of m-NBA were added to the mobile phases of a liquid chromatography...

  13. Increase of faecal tryptic activity relates to changes in the intestinal microbiome: analysis of Crohn's disease with a multidisciplinary platform.

    Directory of Open Access Journals (Sweden)

    Tore Midtvedt

    Full Text Available To investigate-by molecular, classical and functional methods-the microbiota in biopsies and faeces from patients with active Crohn's disease (CD and controls.The microbiota in biopsies was investigated utilizing a novel molecular method and classical cultivation technology. Faecal samples were investigated by classical technology and four functional methods, reflecting alterations in short chain fatty acids pattern, conversion of cholesterol and bilirubin and inactivation of trypsin.By molecular methods we found more than 92% similarity in the microbiota on the biopsies from the two groups. However, 4.6% of microbes found in controls were lacking in CD patients. Furthermore, NotI representation libraries demonstrate two different clusters representing CD patients and controls, respectively. Utilizing conventional technology, Bacteroides (alt. Parabacteroides was less frequently detected in the biopsies from CD patients than from controls. A similar reduction in the number of Bacteroides was found in faecal samples. Bacteroides is the only group of bacteria known to be able to inactivate pancreatic trypsin. Faecal tryptic activity was high in CD patients, and inversely correlated to the levels of Bacteroides.CD patients have compositional and functional alterations in their intestinal microbiota, in line with the global description hypothesis rather than the candidate microorganism theory. The most striking functional difference was high amount of faecal tryptic activity in CD patients, inversely correlated to the levels of Bacteroides in faeces.

  14. Improving off-line accelerated tryptic digestion. Towards fast-lane proteolysis of complex biological samples.

    Science.gov (United States)

    Vukovic, Jadranka; Loftheim, Håvard; Winther, Bjørn; Reubsaet, J Léon E

    2008-06-27

    Off-line digestion of proteins using immobilized trypsin beads is studied with respect to the format of the digestion reactor, the digestion conditions, the comparison with in-solution digestion and its use in complex biological samples. The use of the filter vial as the most appropriate digestion reactor enables simple, efficient and easy-to-handle off-line digestion of the proteins on trypsin beads. It was shown that complex proteins like bovine serum albumin (BSA) need much longer time (89 min) and elevated temperature (37 degrees C) to be digested to an acceptable level compared to smaller proteins like cytochrome c (5 min, room temperature). Comparing the BSA digestion using immobilized trypsin beads with conventional in-solution digestion (overnight at 37 degrees C), it was shown that comparable results were obtained with respect to sequence coverage (>90%) and amount of missed cleavages (in both cases around 20 peptides with 1 or 2 missed cleavages were detected). However, the digestion using immobilized trypsin beads was considerable less time consuming. Good reproducibility and signal intensities were obtained for the digestion products of BSA in a complex urine sample. In addition to this, peptide products of proteins typically present in urine were identified.

  15. Different target surfaces for the analysis of peptides, peptide mixtures and peptide mass fingerprints by AP-MALDI ion trap-mass spectrometry.

    Science.gov (United States)

    Pittenauer, Ernst; Kassler, Alexander; Haubner, Roland; Allmaier, Günter

    2011-06-10

    The desorption/ionization behavior of individual peptides, an equimolare peptide mixture and a tryptic digest was investigated by AP-MALDI-IT-MS using four different target materials (gold-covered stainless steel (SS), titanium nitride-covered SS, hand-polished SS, and microdiamond-covered hardmetal) under identical conditions. Gold-covered as well as polished SS targets yielded comparable mass spectra for peptides and peptide mixture in the low pMol-range. The first target exhibited superior data down to the 10fMol-range. In contrast, titanium nitride-covered SS and microdiamond-covered hardmetal AP-MALDI-targets yielded poor sensitivity. These observations could be correlated with the surface roughness of the targets determined by 3D-confocal-white-light-microscopy. The roughest surfaces were found for titanium nitride-covered SS and microdiamond-covered hardmetal material showing both poor MS sensitivity. A less rough surface could be determined for the hand-polished SS target and the smoothest surface was found for the gold-covered target yielding the best sensitivity of all surfaces. These differences in the roughness having a strong impact on the ultimate sensitivity obtainable for peptide samples could be corroborated by electron microscopy. A peptide mixture covering a wide range of molecular weights and a tryptic protein digest (from 2-DE) exhibit the same behavior. This clearly indicates that the smooth gold-covered SS target is the surface of choice in AP-MALDI MS proteomics. Copyright © 2010. Published by Elsevier B.V.

  16. Generation and characterization of peptide-specific, MHC-restricted cytotoxic T lymphocyte (CTL) and helper T cell lines from unprimed T cells under microculture conditions.

    Science.gov (United States)

    Sambhara, S R; Upadhya, A G; Miller, R G

    1990-06-12

    We describe a microculture system for the generation of CTL and T helper cells against peptides. Tryptic digest and cyanogen bromide fragments of chicken ovalbumin and synthetic peptides of ovalbumin (323-339) and influenza virus (NP 365-380) were used to generate CTL and T helper lines from unprimed T cells. These lines were both peptide-specific and MHC-restricted. The relative ease of generating peptide-specific, MHC-restricted CTL and helper T cell lines with as few as 10(6) unprimed lymphocytes can be an efficient method of detecting potential immunogenic determinants of an antigen.

  17. Preparation and structure characterization of soluble bone collagen ...

    African Journals Online (AJOL)

    In this study, G-25 gel chromatography, X-diffraction, scanning electron microscopy (SEM), UV and Fourier transform infrared spectroscopy (FTIR) were used to analyze soluble collagen peptides chelating calcium. Collagen peptide hydrolysis can be divided into four components using G-25 gel chromatography.

  18. Peptide dendrimers

    Czech Academy of Sciences Publication Activity Database

    Niederhafner, Petr; Šebestík, Jaroslav; Ježek, Jan

    2005-01-01

    Roč. 11, - (2005), 757-788 ISSN 1075-2617 R&D Projects: GA ČR(CZ) GA203/03/1362 Institutional research plan: CEZ:AV0Z40550506 Keywords : multiple antigen peptides * peptide dendrimers * synthetic vaccine * multipleantigenic peptides Subject RIV: CC - Organic Chemistry Impact factor: 1.803, year: 2005

  19. Biosynthesis of amidated joining peptide from pro-adrenocorticotropin-endorphin

    Energy Technology Data Exchange (ETDEWEB)

    Cullen, E.I.; Mains, R.E. (Johns Hopkins Univ. School of Medicine, Baltimore, MD (USA))

    1987-09-01

    Joining peptide is the major alpha-amidated product of pro-ACTH/endorphin (PAE) in AtT-20 corticotropic tumor cells. To study intracellular joining peptide synthesis, affinity purified antibodies directed against gamma-MSH, joining peptide, and ACTH were used to immunoprecipitate extracts from biosynthetically labeled AtT-20 cells. Immunoprecipitates were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by tryptic peptide mapping on HPLC. In steady labeling experiments, radioactivity in amidated joining peptide (JP) increased roughly linearly with time, in the manner of a final product, whereas radioactivity associated with PAE (1-94)NH2 reached a constant value after 2-4 h, indicating that PAE(1-94)NH2 is an intermediate in the biosynthesis of JP. Radioactivity appeared in ACTH(1-39) well before JP, consistent with a cleavage order in which ACTH is cleaved from PAE(1-95) before JP sequences are cleaved from PAE(1-74). This conclusion was supported by tryptic peptide analyses of immunoprecipitates, which indicated that less than 5% of JP-related material is cleaved from PAE(1-74) before being cleaved from ACTH-related sequences. After a pulse label, radioactivity in PAE(1-94)NH2 reached a peak value after 1 h of chase and declined with a half-life of less than 1 h. Amidated JP increased to a constant level after 2 h of chase. Enough radiolabeled PAE(1-94)NH2 was detected to account for about half of the radioactivity found in amidated JP, indicating that about half of JP-related material is first cleaved from PAE(1-95) before being amidated. This result was corroborated using HPLC purification to determine both amidated and glycine-extended forms of JP.

  20. Biosynthesis of amidated joining peptide from pro-adrenocorticotropin-endorphin

    International Nuclear Information System (INIS)

    Cullen, E.I.; Mains, R.E.

    1987-01-01

    Joining peptide is the major alpha-amidated product of pro-ACTH/endorphin (PAE) in AtT-20 corticotropic tumor cells. To study intracellular joining peptide synthesis, affinity purified antibodies directed against gamma-MSH, joining peptide, and ACTH were used to immunoprecipitate extracts from biosynthetically labeled AtT-20 cells. Immunoprecipitates were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by tryptic peptide mapping on HPLC. In steady labeling experiments, radioactivity in amidated joining peptide (JP) increased roughly linearly with time, in the manner of a final product, whereas radioactivity associated with PAE (1-94)NH2 reached a constant value after 2-4 h, indicating that PAE(1-94)NH2 is an intermediate in the biosynthesis of JP. Radioactivity appeared in ACTH(1-39) well before JP, consistent with a cleavage order in which ACTH is cleaved from PAE(1-95) before JP sequences are cleaved from PAE(1-74). This conclusion was supported by tryptic peptide analyses of immunoprecipitates, which indicated that less than 5% of JP-related material is cleaved from PAE(1-74) before being cleaved from ACTH-related sequences. After a pulse label, radioactivity in PAE(1-94)NH2 reached a peak value after 1 h of chase and declined with a half-life of less than 1 h. Amidated JP increased to a constant level after 2 h of chase. Enough radiolabeled PAE(1-94)NH2 was detected to account for about half of the radioactivity found in amidated JP, indicating that about half of JP-related material is first cleaved from PAE(1-95) before being amidated. This result was corroborated using HPLC purification to determine both amidated and glycine-extended forms of JP

  1. Capillary electrophoretic profiling of tryptic digests of water soluble proteins from Bacillus thuringiensis-transgenic and non-transgenic maize species

    Czech Academy of Sciences Publication Activity Database

    Sázelová, Petra; Kašička, Václav; Leon, C.; Ibanez, E.; Cifuentes, A.

    2012-01-01

    Roč. 134, č. 3 (2012), s. 1607-1615 ISSN 0308-8146 R&D Projects: GA ČR(CZ) GA203/08/1428 Grant - others:AV ČR(CZ) 2008CZ0019 Institutional research plan: CEZ:AV0Z40550506 Keywords : Bt-transgenic maize * capillary zone electrophoresis * maize proteins Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.334, year: 2012

  2. A novel sensitive sheathless CE-MS device for peptide and protein analysis

    DEFF Research Database (Denmark)

    Nguyen, Tam T. T. N.; Petersen, Nickolaj J.; Rand, Kasper Dyrberg

    analysis. By analysis of a model peptide (Leucine Enkephalin), a limit of detection (LOD) of 0.045 pmol/µL (corresponding to 67 attomol in a sample volume of ~ 15 nL) was obtained. The merit of the CE-MS approach was demonstrated by analysis of bovine serum albumin (BSA) tryptic peptides. A well......Ab (Rituximab) suggesting significant real-world applicability in biopharmaceutical research. Finally, by employing a native CE buffer (ammonium acetate, pH 6), we show that the CE-MS interface facilitates gentle ESI of proteins, opening up for native MS applications in combination with ion mobility and other...

  3. New dendrimer - peptide host - guest complexes : towards dendrimers as peptide carriers

    NARCIS (Netherlands)

    Boas, U.; Sontjens, S.H.M.; Jensen, K.J.; Christensen, J.B.; Meijer, E.W.

    2002-01-01

    Adamantyl urea and adamantyl thiourea modified poly(propylene imine) dendrimers act as hosts for N-terminal tert-butoxycarbonyl (Boc)-protected peptides and form chloroform-soluble complexes. investigations with NMR spectroscopy show that the peptide is bound to the dendrimer by ionic interactions

  4. Identification of Cellular Binding Sites for a Novel Human Anti-Breast Cancer Peptide

    National Research Council Canada - National Science Library

    DeFreest, Lori

    2004-01-01

    ... breast cancer growth. We have developed and optimized an affinity chromatography procedure to identify the receptor for AFPep by using the peptide as "bait" to isolate proteins from solublized cells which have an affinity for the peptide...

  5. De novo sequencing of two novel peptides homologous to calcitonin-like peptides, from skin secretion of the Chinese Frog, Odorrana schmackeri

    Directory of Open Access Journals (Sweden)

    Geisa P.C. Evaristo

    2015-09-01

    Full Text Available An MS/MS based analytical strategy was followed to solve the complete sequence of two new peptides from frog (Odorrana schmackeri skin secretion. This involved reduction and alkylation with two different alkylating agents followed by high resolution tandem mass spectrometry. De novo sequencing was achieved by complementary CID and ETD fragmentations of full-length peptides and of selected tryptic fragments. Heavy and light isotope dimethyl labeling assisted with annotation of sequence ion series. The identified primary structures are GCD[I/L]STCATHN[I/L]VNE[I/L]NKFDKSKPSSGGVGPESP-NH2 and SCNLSTCATHNLVNELNKFDKSKPSSGGVGPESF-NH2, i.e. two carboxyamidated 34 residue peptides with an aminoterminal intramolecular ring structure formed by a disulfide bridge between Cys2 and Cys7. Edman degradation analysis of the second peptide positively confirmed the exact sequence, resolving I/L discriminations. Both peptide sequences are novel and share homology with calcitonin, calcitonin gene related peptide (CGRP and adrenomedullin from other vertebrates. Detailed sequence analysis as well as the 34 residue length of both O. schmackeri peptides, suggest they do not fully qualify as either calcitonins (32 residues or CGRPs (37 amino acids and may justify their classification in a novel peptide family within the calcitonin gene related peptide superfamily. Smooth muscle contractility assays with synthetic replicas of the S–S linked peptides on rat tail artery, uterus, bladder and ileum did not reveal myotropic activity.

  6. Refining comparative proteomics by spectral counting to account for shared peptides and multiple search engines.

    Science.gov (United States)

    Chen, Yao-Yi; Dasari, Surendra; Ma, Ze-Qiang; Vega-Montoto, Lorenzo J; Li, Ming; Tabb, David L

    2012-09-01

    Spectral counting has become a widely used approach for measuring and comparing protein abundance in label-free shotgun proteomics. However, when analyzing complex samples, the ambiguity of matching between peptides and proteins greatly affects the assessment of peptide and protein inventories, differentiation, and quantification. Meanwhile, the configuration of database searching algorithms that assign peptides to MS/MS spectra may produce different results in comparative proteomic analysis. Here, we present three strategies to improve comparative proteomics through spectral counting. We show that comparing spectral counts for peptide groups rather than for protein groups forestalls problems introduced by shared peptides. We demonstrate the advantage and flexibility of this new method in two datasets. We present four models to combine four popular search engines that lead to significant gains in spectral counting differentiation. Among these models, we demonstrate a powerful vote counting model that scales well for multiple search engines. We also show that semi-tryptic searching outperforms tryptic searching for comparative proteomics. Overall, these techniques considerably improve protein differentiation on the basis of spectral count tables.

  7. Assessment of meat authenticity using bioinformatics, targeted peptide biomarkers and high-resolution mass spectrometry.

    Science.gov (United States)

    Ruiz Orduna, Alberto; Husby, Erik; Yang, Charles T; Ghosh, Dipankar; Beaudry, Francis

    2015-01-01

    In recent years a significant increase of food fraud has been observed, ranging from false label claims to the use of additives and fillers to increase profitability. Recently in 2013 horse and pig DNAs were detected in beef products sold from several retailers. Mass spectrometry (MS) has become the workhorse in protein research, and the detection of marker proteins could serve for both animal species and tissue authentication. Meat species authenticity is performed in this paper using a well-defined proteogenomic annotation, carefully chosen surrogate tryptic peptides and analysis using a hybrid quadrupole-Orbitrap MS. Selected mammalian meat samples were homogenised and proteins were extracted and digested with trypsin. The samples were analysed using a high-resolution MS. Chromatography was achieved using a 30-min linear gradient along with a BioBasic C8 100 × 1 mm column at a flow rate of 75 µl min(-1). The MS was operated in full-scan high resolution and accurate mass. MS/MS spectra were collected for selected proteotypic peptides. Muscular proteins were methodically analysed in silico in order to generate tryptic peptide mass lists and theoretical MS/MS spectra. Following a comprehensive bottom-up proteomic analysis, we detected and identified a proteotypic myoglobin tryptic peptide (120-134) for each species with observed m/z below 1.3 ppm compared with theoretical values. Moreover, proteotypic peptides from myosin-1, myosin-2 and β-haemoglobin were also identified. This targeted method allowed comprehensive meat speciation down to 1% (w/w) of undesired product.

  8. New dendrimer - Peptide host - Guest complexes: Towards dendrimers as peptide carriers

    DEFF Research Database (Denmark)

    Boas, Ulrik; Sontjens, S.H.M.; Jensen, Knud Jørgen

    2002-01-01

    Adamantyl urea and adamantyl thiourea modified poly(propylene imine) dendrimers act as hosts for N-terminal tert-butoxycarbonyl (Boc)-protected peptides and form chloroform-soluble complexes. investigations with NMR spectroscopy show that the peptide is bound to the dendrimer by ionic interactions...... between the dendrimer outer shell tertiary amines and the C-terminal carboxylic acid of the peptide, and also through host-urea to peptide-amide hydrogen bonding. The hydrogen-bonding nature of the peptide dendrimer interactions was further confirmed by using Fourier transform IR spectroscopy, for which...... the NH- and CO-stretch signals of the peptide amide moieties shift towards lower wave-numbers upon complexation with the dendrimer. Spatial analysis of the complexes with NOESY spectroscopy generally shows close proximity of the N-terminal Boc group of the peptide to the peripheral adamantyl groups...

  9. Gas solubilities widespread applications

    CERN Document Server

    Gerrard, William

    1980-01-01

    Gas Solubilities: Widespread Applications discusses several topics concerning the various applications of gas solubilities. The first chapter of the book reviews Henr's law, while the second chapter covers the effect of temperature on gas solubility. The third chapter discusses the various gases used by Horiuti, and the following chapters evaluate the data on sulfur dioxide, chlorine data, and solubility data for hydrogen sulfide. Chapter 7 concerns itself with solubility of radon, thoron, and actinon. Chapter 8 tackles the solubilities of diborane and the gaseous hydrides of groups IV, V, and

  10. LC/MSMS STUDY OF BENZO[A]PYRENE-7,8-QUINONE ADDUCTION TO GLOBIN TRYPTIC PEPTIDES AND N-ACETYLAMINO ACIDS

    Science.gov (United States)

    Benzo[a]pyrene-7,8-quinone (BPQ) is regarded as a reactive genotoxic compound enzymatically formed from a xenobiotic precursor benzo[a]pyrene-7,8-diol by aldo-keto-reductase family of enzymes. Because BPQ, a Michael electrophile, was previously shown to react with oligonucleotide...

  11. Neptunium (IV) oxalate solubility

    International Nuclear Information System (INIS)

    Luerkens, D.W.

    1983-07-01

    The equilibrium solubility of neptunium (IV) oxalate in nitric/oxalic acid solutions was determined at 22 0 C, 45 0 C, and 60 0 C. The concentrations of nitric/oxalic acid solutions represented a wide range of free oxalate ion concentration. A mathematical solubility model was developed which is based on the formation of the known complexes of neptunium (IV) oxalate. the solubility model uses a simplified concentration parameter which is proportional to the free oxalate ion concentration. The solubility model can be used to estimate the equilibrium solubility of neptunium (IV) oxalate over a wide range of oxalic and nitric acid concentrations at each temperature

  12. Cysteine-containing peptides having antioxidant properties

    Science.gov (United States)

    Bielicki, John K [Castro Valley, CA

    2008-10-21

    Cysteine containing amphipathic alpha helices of the exchangeable apolipoproteins, as exemplified by apolipoprotein (apo) A-I.sub.Milano (R173C) and apoA-I.sub.Paris, (R151C) were found to exhibit potent antioxidant activity on phospholipid surfaces. The addition of a free thiol, at the hydrophobic/hydrophilic interface of an amphipathic alpha helix of synthetic peptides that mimic HDL-related proteins, imparts a unique antioxidant activity to these peptides which inhibits lipid peroxidation and protects phospholipids from water-soluble free radical initiators. These peptides can be used as therapeutic agents to combat cardiovascular disease, ischemia, bone disease and other inflammatory related diseases.

  13. Soluble mediators and the interaction of drugs in IBD

    DEFF Research Database (Denmark)

    Rask-Madsen, J

    1998-01-01

    and 5-aminosalicylic acid (5-ASA), inhibit raised concentrations of these interdependent soluble mediators of inflammation, which may amplify one another or have parallel effects. Future medical options for treatment of IBD aim at removing perpetuating antigens or inhibiting the entry of inflammatory......, which provides the clinical manifestations of IBD. Other important soluble mediators of inflammation include complement-derived and chemotactic peptides, specific adhesion molecules, neuropeptides and reactive metabolites of oxygen and nitrogen. Current established therapies, such as glucocorticoids...

  14. Peptide Nucleic Acids Having Amino Acid Side Chains

    DEFF Research Database (Denmark)

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary DNA and RNA strands more strongly than the corresponding DNA or RNA strands, and exhibit increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from a group consisting...

  15. Identification of a novel Plasmopara halstedii elicitor protein combining de novo peptide sequencing algorithms and RACE-PCR

    Directory of Open Access Journals (Sweden)

    Madlung Johannes

    2010-05-01

    Full Text Available Abstract Background Often high-quality MS/MS spectra of tryptic peptides do not match to any database entry because of only partially sequenced genomes and therefore, protein identification requires de novo peptide sequencing. To achieve protein identification of the economically important but still unsequenced plant pathogenic oomycete Plasmopara halstedii, we first evaluated the performance of three different de novo peptide sequencing algorithms applied to a protein digests of standard proteins using a quadrupole TOF (QStar Pulsar i. Results The performance order of the algorithms was PEAKS online > PepNovo > CompNovo. In summary, PEAKS online correctly predicted 45% of measured peptides for a protein test data set. All three de novo peptide sequencing algorithms were used to identify MS/MS spectra of tryptic peptides of an unknown 57 kDa protein of P. halstedii. We found ten de novo sequenced peptides that showed homology to a Phytophthora infestans protein, a closely related organism of P. halstedii. Employing a second complementary approach, verification of peptide prediction and protein identification was performed by creation of degenerate primers for RACE-PCR and led to an ORF of 1,589 bp for a hypothetical phosphoenolpyruvate carboxykinase. Conclusions Our study demonstrated that identification of proteins within minute amounts of sample material improved significantly by combining sensitive LC-MS methods with different de novo peptide sequencing algorithms. In addition, this is the first study that verified protein prediction from MS data by also employing a second complementary approach, in which RACE-PCR led to identification of a novel elicitor protein in P. halstedii.

  16. Quantification of trypsin with a radioimmunoassay in herring larvae (Clupea harengus L.) compared with a highly sensitive fluorescence technique to determine tryptic enzyme activity

    International Nuclear Information System (INIS)

    Ueberschaer, B.; Pedersen, B.H.; Hjelmeland, K.

    1993-01-01

    Enzymatic activity and quantity of the protease trypsin were measured in individual herring larvae (Clupea harengus L.). The enzymatic activity assay was done by a fluorescence technique, and a radioimmunoassay was used for quantification of trypsin. The results are compared and the differences between the techniques discussed. Both methods have similar results, as high or low values in trypsin quantity were reflected in high or low values of tryptic activity. Quantity and activity were linearly and positively correlated, but small differences between methods were found at the lowest detection limits. Both techniques reflect the high variability between individual larvae. (orig.)

  17. Selection of possible signature peptides for the detection of bovine lactoferrin in infant formulas by LC-MS/MS.

    Directory of Open Access Journals (Sweden)

    Mingmei Yuan

    Full Text Available An LC-MS/MS assay based on a signature peptide was developed and fully validated for the quantitation of bovine lactoferrin in infant formulas. Three unreported signature peptides were derived and identified from the tryptic peptides of bovine lactoferrin. The peptide ETTVFENLPEK was used for quantification based on assay performance. The blank matrix camel milk powder and bovine lactoferrin protein standards were mixed and spiked with stable isotope-labeled internal standard to establish a calibration curve. The established method was extensively validated by determining the linearity (R2 > 0.999, sensitivity (limit of quantitation, 0.16 mg/100 g, recovery (83.1-91.6%, precision (RSD < 5.4% and repeatability (RSD < 7.7%. To validate the applicability of the method, four different brands of infant formulas in China were analysed. The acquired contents of bovine lactoferrin were 52.60-150.56 mg/100 g.

  18. Matrix-assisted laser desorption/ionization time of flight mass spectrometry peptide mass fingerprints and post source decay: a tool for the identification and analysis of phloem proteins from Cucurbita maxima Duch. separated by two-dimensional polyacrylamide gel electrophoresis.

    Science.gov (United States)

    Haebel, S; Kehr, J

    2001-08-01

    A combination of gel electrophoresis and mass spectrometry was used to analyze the soluble proteins from phloem sap of Cucurbita maxima Duch. Phloem proteins were separated using two-dimensional gel electrophoresis. Coomassie-stained spots were cut out and subjected to tryptic digestion. To identify proteins, peptide mass fingerprints were determined by matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry. In addition, MALDI-TOF post source decay measurements were used to obtain partial sequence information for the proteins. Results from both approaches were used for database searches. In this study, 17 proteins in the mass range 5-50 kDa were analyzed. Of these proteins six could be clearly identified, seven showed significant homologies to known plant proteins, and four were not significantly homologous to database entries. The present study suggests that the applied method is feasible for a large-scale analysis and identification of phloem proteins derived from different organs or from plants kept under various physiological conditions.

  19. Efeito da hidrólise tríptica e do pH sobre as propriedades funcionais do plasma bovino The effect of the tryptic hydrolysis and the pH on the functional properties of bovine plasma

    Directory of Open Access Journals (Sweden)

    Cléia Batista Dias Ornellas

    2003-04-01

    Full Text Available Visando a utilização do plasma bovino como agente funcional de alimentos, foram estudadas, na faixa de pH de 3,0 a 8,0, a solubilidade, a hidrofobicidade e a sua habilidade de formar e estabilizar emulsões. Para tal, foram determinados a capacidade emulsionante (EC, o índice de atividade emulsionante (EAI e a estabilidade da emulsão (ES. O efeito da ação da tripsina sobre estas propriedades foi, também, verificado, tendo sido preparados cinco hidrolisados enzimáticos. Os resultados obtidos indicam que a hidrofobicidade e o EAI apresentaram um máximo em pH 3,0 e 7,0, respectivamente, enquanto que as outras propriedades praticamente não foram influenciadas pela variação de pH. A hidrólise tríptica provocou uma redução da solubilidade e da EC, não afetou o EAI e a ES, tendo contribuído para melhorar apenas a hidrofobicidade, em alguns tempos de reação.Aiming to use of the bovine plasma as functional agent of foods, we studied its solubility, hidrophobicity and ability to form and to stabilize emulsions, in the range of pH from 3.0 to 8.0. Emulsifying capacity (EC, the emulsifying activity index (EAI and the stability of the emulsion (ES were determinated. The effect of the trypsin on these properties was also studied and five enzymatic hydrolysates were prepared. The results showed that hydrophobicity and EAI presented a maximum value at pH 3.0 and 7.0, respectively, while the other properties practically were not influenced by the pH variation. The tryptic hydrolysis produced a reduction of the solubility and EC, it showed no effect on EAI and ES and improved only the hidrophobicity in some periods of reaction.

  20. Soluble Non-ammonia Nitrogen in Ruminal and Omasal Digesta of Korean Native Steers Supplemented with Soluble Proteins

    Directory of Open Access Journals (Sweden)

    C. W. Choi

    2012-09-01

    Full Text Available An experiment was conducted to study the effect of soluble protein supplements on concentration of soluble non-ammonia nitrogen (SNAN in the liquid phase of ruminal (RD and omasal digesta (OD of Korean native steers, and to investigate diurnal pattern in SNAN concentration in RD and OD. Three ruminally cannulated Korean native steers in a 3×3 Latin square design consumed a basal diet of rice straw and corn-based concentrate (control, and that supplemented (kg/d DM basis with intact casein (0.24; IC or acid hydrolyzed casein (0.46; AHC. Ruminal digesta was sampled using a vacuum pump, whereas OD was collected using an omasal sampling system at 2.0 h intervals after a morning feeding. The SNAN fractions (free amino acid (AA, peptide and soluble protein in RD and OD were assessed using the ninhydrin assay. Concentrations of free AA and total SNAN in RD were significantly (p<0.05 lower than those in OD. Although free AA concentration was relatively high, mean peptide was quantitatively the most important fraction of total SNAN in both RD and OD, indicating that degradation of peptide to AA rather than hydrolysis of soluble protein to peptide or deamination may be the most limiting step in rumen proteolysis of Korean native steers. Diurnal variation in peptide concentration in OD for the soluble protein supplemented diets during the feeding cycle peaked 2 h post-feeding and decreased thereafter whereas that for the control was relatively constant during the entire feeding cycle. Diurnal variation in peptide concentration was rather similar between RD and OD.

  1. Peptide chemistry toolbox - Transforming natural peptides into peptide therapeutics.

    Science.gov (United States)

    Erak, Miloš; Bellmann-Sickert, Kathrin; Els-Heindl, Sylvia; Beck-Sickinger, Annette G

    2018-06-01

    The development of solid phase peptide synthesis has released tremendous opportunities for using synthetic peptides in medicinal applications. In the last decades, peptide therapeutics became an emerging market in pharmaceutical industry. The need for synthetic strategies in order to improve peptidic properties, such as longer half-life, higher bioavailability, increased potency and efficiency is accordingly rising. In this mini-review, we present a toolbox of modifications in peptide chemistry for overcoming the main drawbacks during the transition from natural peptides to peptide therapeutics. Modifications at the level of the peptide backbone, amino acid side chains and higher orders of structures are described. Furthermore, we are discussing the future of peptide therapeutics development and their impact on the pharmaceutical market. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Heat-induced alterations in cashew allergen solubility and IgE binding

    Directory of Open Access Journals (Sweden)

    Christopher P. Mattison

    Full Text Available Cashew nuts are an increasingly common cause of food allergy. We compare the soluble protein profile of cashew nuts following heating. SDS-PAGE indicate that heating can alter the solubility of cashew nut proteins. The 11S legumin, Ana o 2, dominates the soluble protein content in ready to eat and mildly heated cashew nuts. However, we found that in dark-roasted cashew nuts, the soluble protein profile shifts and the 2S albumin Ana o 3 composes up to 40% of the soluble protein. Analysis of trypsin-treated extracts by LC/MS/MS indicate changes in the relative number and intensity of peptides. The relative cumulative intensity of the 5 most commonly observed Ana o 1 and 2 peptides are altered by heating, while those of the 5 most commonly observed Ana o 3 peptides remaine relatively constant. ELISA experiments indicate that there is a decrease in rabbit IgG and human serum IgE binding to soluble cashew proteins following heating. Our findings indicate that heating can alter the solubility of cashew allergens, resulting in altered IgE binding. Our results support the use of both Ana o 2 and Ana o 3 as potential cashew allergen diagnostic targets. Keywords: Cashew nut, Food allergy, Immunoglobulin E, Mass-spectrometry, Peptide, Solubility

  3. Sequence-Specific Model for Peptide Retention Time Prediction in Strong Cation Exchange Chromatography.

    Science.gov (United States)

    Gussakovsky, Daniel; Neustaeter, Haley; Spicer, Victor; Krokhin, Oleg V

    2017-11-07

    The development of a peptide retention prediction model for strong cation exchange (SCX) separation on a Polysulfoethyl A column is reported. Off-line 2D LC-MS/MS analysis (SCX-RPLC) of S. cerevisiae whole cell lysate was used to generate a retention dataset of ∼30 000 peptides, sufficient for identifying the major sequence-specific features of peptide retention mechanisms in SCX. In contrast to RPLC/hydrophilic interaction liquid chromatography (HILIC) separation modes, where retention is driven by hydrophobic/hydrophilic contributions of all individual residues, SCX interactions depend mainly on peptide charge (number of basic residues at acidic pH) and size. An additive model (incorporating the contributions of all 20 residues into the peptide retention) combined with a peptide length correction produces a 0.976 R 2 value prediction accuracy, significantly higher than the additive models for either HILIC or RPLC. Position-dependent effects on peptide retention for different residues were driven by the spatial orientation of tryptic peptides upon interaction with the negatively charged surface functional groups. The positively charged N-termini serve as a primary point of interaction. For example, basic residues (Arg, His, Lys) increase peptide retention when located closer to the N-terminus. We also found that hydrophobic interactions, which could lead to a mixed-mode separation mechanism, are largely suppressed at 20-30% of acetonitrile in the eluent. The accuracy of the final Sequence-Specific Retention Calculator (SSRCalc) SCX model (∼0.99 R 2 value) exceeds all previously reported predictors for peptide LC separations. This also provides a solid platform for method development in 2D LC-MS protocols in proteomics and peptide retention prediction filtering of false positive identifications.

  4. Assessing high affinity binding to HLA-DQ2.5 by a novel peptide library based approach

    DEFF Research Database (Denmark)

    Jüse, Ulrike; Arntzen, Magnus; Højrup, Peter

    2011-01-01

    Here we report on a novel peptide library based method for HLA class II binding motif identification. The approach is based on water soluble HLA class II molecules and soluble dedicated peptide libraries. A high number of different synthetic peptides are competing to interact with a limited amount...... library. The eluted sequences fit very well with the previously described HLA-DQ2.5 peptide binding motif. This novel method, limited by library complexity and sensitivity of mass spectrometry, allows the analysis of several thousand synthetic sequences concomitantly in a simple water soluble format....

  5. Statistical Characterization of the Charge State and Residue Dependence of Low-Energy CID Peptide Dissociation Patterns

    International Nuclear Information System (INIS)

    Huang, Yingying; Triscari, Joseph M.; Tseng, George C.; Pasa-Tolic, Ljiljana; Lipton, Mary S.; Smith, Richard D.; Wysocki, Vicki H.

    2005-01-01

    Data mining was performed on 28 330 unique peptide tandem mass spectra for which sequences were assigned with high confidence. By dividing the spectra into different sets based on structural features and charge states of the corresponding peptides, chemical interactions involved in promoting specific cleavage patterns in gas-phase peptides were characterized. Pairwise fragmentation maps describing cleavages at all Xxx-Zzz residue combinations for b and y ions reveal that the difference in basicity between Arg and Lys results in different dissociation patterns for singly charged Arg- and Lys-ending tryptic peptides. While one dominant protonation form (proton localized) exists for Arg-ending peptides, a heterogeneous population of different protonated forms or more facile interconversion of protonated forms (proton partially mobile) exists for Lys-ending peptides. Cleavage C-terminal to acidic residues dominates spectra from peptides that have a localized proton and cleavage N-terminal to Pro dominates those that have a mobile or partially mobile proton. When Pro is absent from peptides that have a mobile or partially mobile proton, cleavage at each peptide bond becomes much more prominent. Whether the above patterns can be found in b ions, y ions, or both depends on the location of the proton holder(s). Enhanced cleavages C-terminal to branched aliphatic residues (Ile, Val, Leu) are observed in both b and y ions from peptides that have a mobile proton, as well as in y ions from peptides that have a partially mobile proton; enhanced cleavages N-terminal to these residues are observed in b ions from peptides that have a partially mobile proton. Statistical tools have been designed to visualize the fragmentation maps and measure the similarity between them. The pairwise cleavage patterns observed expand our knowledge of peptide gas-phase fragmentation behaviors and should be useful in algorithm development that employs improved models to predict fragment ion

  6. Iodinated derivatives of vasoactive intestinal peptide (VIP), PHI and PHM: purification, chemical characterization and biological activity

    International Nuclear Information System (INIS)

    McMaster, D.; Suzuki, Y.; Rorstad, O.; Lederis, K.

    1987-01-01

    The iodination of vasoactive intestinal peptide (VIP) was studied, using a variety of enzymatic and chemical iodination methods. Reversed phase high performance liquid chromatography (HPLC) was used to purify the reaction products. The lactoperoxidase-glucose oxidase method gave excellent results in terms of reproducibility, iodine incorporation, and yield of the non-oxidized products [Tyr(I)10]VIP and [Tyr(I)22]VIP, and was used to prepare both 125 I and 127 I labelled derivatives. In both cases, direct application to HPLC and a single column system were used. Although the oxidized peptides [Tyr(I)10,Met(O)17]VIP and [Tyr(I)22,Met(O)17]VIP could be generated to varying degrees directly by iodination of VIP, these were most conveniently prepared by iodination of [Met(O)17]VIP. Iodinated derivatives of the homologous peptides PHI and PHM were likewise prepared by rapid, one-step HPLC procedures. The site and degree of iodination were determined by HPLC peptide mapping of tryptic digests and amino acid analyses, and in the case of [Tyr(I)10]VIP also by sequencing. The vasorelaxant activities of the iodinated peptides in bovine cerebral artery preparations did not differ significantly from those of the corresponding noniodinated peptides, with the exception of [Tyr(I)10,Met(O)17]VIP and [Tyr(I)22,Met(O)17]VIP which, unlike [Met(O)17]VIP itself, had slightly lower potency than VIP

  7. Synthesis of stable isotopically labeled peptides with filter-assisted enzymatic labeling for the diagnosis of hepatitis B virus infection utilizing mass spectrometry-based proteomics strategy

    International Nuclear Information System (INIS)

    Tsai, Hsing-Fen; Hsiao, He-Hsuan

    2017-01-01

    A facile method for the preparation of stable isotopically labeled peptides was developed by means of filter-assisted tryptic "1"6O/"1"8O water labeling, which could be directly applied to the determination of hepatitis B virus infection from human serum with tandem mass spectrometry. Tryptic peptides of hepatitis B surface antigen or hepatitis B e antigen from different subtypes of hepatitis B virus were synthesized with traditional solid-phase peptide synthesis as potential biomarkers. Trypsin catalyzed oxygen-18 exchange at their amidated c-terminus of arginine or lysine residue. The protease catalyzed oxygen-18 to oxygen-16 back exchange reaction was eliminated due to the complete removal of trypsin by the centrifugal filter containing a thin membrane associated with molecular weight cut-off of 10 KDa. The synthetic isotopic peptides were spiked into trichloroacetic acid/acetone precipitated human serum as internal standards and were selectively detected with multiplexed parallel reaction monitoring on a hybrid quadrupole-orbitrap mass spectrometer. The limit of detection for all synthetic peptides were in the range of 0.09 fmol–1.13 fmol. The results indicated that the peptide YLWEWASVR derived from hepatitis B surface antigen was quantified approximately 200 fmol per μl serum and may serve as a diagnostic biomarker for the detection of hepatitis B virus infected disease. - Highlights: • Facile synthesis of an inexpensive and highly reproducible stable isotopically labeled peptides. • Complete incorporation of two "1"8O atoms into synthesized peptides with filter-assisted enzymatic labeling. • Targeted analysis with parallel reaction monitoring assay for the disease diagnosis.

  8. Synthesis of stable isotopically labeled peptides with filter-assisted enzymatic labeling for the diagnosis of hepatitis B virus infection utilizing mass spectrometry-based proteomics strategy

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Hsing-Fen; Hsiao, He-Hsuan, E-mail: hhhsiao@dragon.nchu.edu.tw

    2017-03-01

    A facile method for the preparation of stable isotopically labeled peptides was developed by means of filter-assisted tryptic {sup 16}O/{sup 18}O water labeling, which could be directly applied to the determination of hepatitis B virus infection from human serum with tandem mass spectrometry. Tryptic peptides of hepatitis B surface antigen or hepatitis B e antigen from different subtypes of hepatitis B virus were synthesized with traditional solid-phase peptide synthesis as potential biomarkers. Trypsin catalyzed oxygen-18 exchange at their amidated c-terminus of arginine or lysine residue. The protease catalyzed oxygen-18 to oxygen-16 back exchange reaction was eliminated due to the complete removal of trypsin by the centrifugal filter containing a thin membrane associated with molecular weight cut-off of 10 KDa. The synthetic isotopic peptides were spiked into trichloroacetic acid/acetone precipitated human serum as internal standards and were selectively detected with multiplexed parallel reaction monitoring on a hybrid quadrupole-orbitrap mass spectrometer. The limit of detection for all synthetic peptides were in the range of 0.09 fmol–1.13 fmol. The results indicated that the peptide YLWEWASVR derived from hepatitis B surface antigen was quantified approximately 200 fmol per μl serum and may serve as a diagnostic biomarker for the detection of hepatitis B virus infected disease. - Highlights: • Facile synthesis of an inexpensive and highly reproducible stable isotopically labeled peptides. • Complete incorporation of two {sup 18}O atoms into synthesized peptides with filter-assisted enzymatic labeling. • Targeted analysis with parallel reaction monitoring assay for the disease diagnosis.

  9. Human peptide transporters

    DEFF Research Database (Denmark)

    Nielsen, Carsten Uhd; Brodin, Birger; Jørgensen, Flemming Steen

    2002-01-01

    Peptide transporters are epithelial solute carriers. Their functional role has been characterised in the small intestine and proximal tubules, where they are involved in absorption of dietary peptides and peptide reabsorption, respectively. Currently, two peptide transporters, PepT1 and PepT2, wh...

  10. Facile Synthesis of Mesocrystalline SnO2 Nanorods on Reduced Graphene Oxide Sheets: An Appealing Multifunctional Affinity Probe for Sequential Enrichment of Endogenous Peptides and Phosphopeptides.

    Science.gov (United States)

    Ma, Wen; Zhang, Feng; Li, Liping; Chen, Shuai; Qi, Limin; Liu, Huwei; Bai, Yu

    2016-12-28

    A novel multifunctional composite comprising mesocrystalline SnO 2 nanorods (NRs) vertically aligned on reduced graphene oxide (rGO) sheets was synthesized and developed for sequential capture of endogenous peptides and phosphopeptides. With the hydrophobicity of rGO and high affinity of SnO 2 nanorods, sequential enrichment of endogenous peptides and phosphopeptides could be easily achieved through a modulation of elution buffer. With this multifunctional nanomaterial, 36 peptides were observed from diluted bovine serum albumin (BSA) tryptic digest and 4 phosphopeptides could be selectively captured from β-casein digest. The detection limit of tryptic digest of β-casein was low to 4 × 10 -10 M, and the selectivity was up to 1:500 (molar ratio of β-casein and BSA digest). The effectiveness and robustness of rGO-SnO 2 NRs in a complex biological system was also confirmed by using human serum as a real sample. Our work is promising for small peptide enrichment and identification especially in complicated biological sample preparation, which also opens a new perspective in the design of multifunctional affinity probes for proteome or peptidome.

  11. The membranotropic activity of N-terminal peptides from the pore ...

    Indian Academy of Sciences (India)

    how these water-soluble proteins bind, oligomerize and eventually disrupt target .... Creek, CA, USA), using UV detection at 220 nm. The identity of the peptides ... leakage of dye was negligible under these conditions. Maximum release was ...

  12. Soluble CD163

    DEFF Research Database (Denmark)

    Møller, Holger J

    2012-01-01

    CD163 is an endocytic receptor for haptoglobin-hemoglobin complexes and is expressed solely on macrophages and monocytes. As a result of ectodomain shedding, the extracellular portion of CD163 circulates in blood as a soluble protein (sCD163) at 0.7-3.9 mg/l in healthy individuals. The function o...

  13. Solubility Part 1

    NARCIS (Netherlands)

    Tantra, Ratna; Bolea, Eduardo; Bouwmeester, H.; Rey-Castro, Carlos; David, C.A.A.; Dogné, Jean Michel; Laborda, Francisco; Laloy, Julie; Robinson, Kenneth N.; Undas, A.K.; Zande, van der M.

    2016-01-01

    This chapter gives an overview of different methods that can potentially be used to determine the solubility of nanomaterials. In general, the methods presented can be broadly divided into four categories: separation methods, methods to quantify free ions, methods to quantify total dissolved

  14. PROCAL: A Set of 40 Peptide Standards for Retention Time Indexing, Column Performance Monitoring, and Collision Energy Calibration.

    Science.gov (United States)

    Zolg, Daniel Paul; Wilhelm, Mathias; Yu, Peng; Knaute, Tobias; Zerweck, Johannes; Wenschuh, Holger; Reimer, Ulf; Schnatbaum, Karsten; Kuster, Bernhard

    2017-11-01

    Beyond specific applications, such as the relative or absolute quantification of peptides in targeted proteomic experiments, synthetic spike-in peptides are not yet systematically used as internal standards in bottom-up proteomics. A number of retention time standards have been reported that enable chromatographic aligning of multiple LC-MS/MS experiments. However, only few peptides are typically included in such sets limiting the analytical parameters that can be monitored. Here, we describe PROCAL (ProteomeTools Calibration Standard), a set of 40 synthetic peptides that span the entire hydrophobicity range of tryptic digests, enabling not only accurate determination of retention time indices but also monitoring of chromatographic separation performance over time. The fragmentation characteristics of the peptides can also be used to calibrate and compare collision energies between mass spectrometers. The sequences of all selected peptides do not occur in any natural protein, thus eliminating the need for stable isotope labeling. We anticipate that this set of peptides will be useful for multiple purposes in individual laboratories but also aiding the transfer of data acquisition and analysis methods between laboratories, notably the use of spectral libraries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Charge State Coalescence During Electrospray Ionization Improves Peptide Identification by Tandem Mass Spectrometry

    Science.gov (United States)

    Meyer, Jesse G.; A. Komives, Elizabeth

    2012-08-01

    We report the effects of supercharging reagents dimethyl sulphoxide (DMSO) and m-nitrobenzyl alcohol ( m-NBA) applied to untargeted peptide identification, with special emphasis on non-tryptic peptides. Peptides generated from a mixture of five standard proteins digested with trypsin, elastase, or pepsin were separated with nanoflow liquid chromatography using mobile phases modified with either 5 % DMSO or 0.1 % m-NBA. Eluting peptides were ionized by online electrospray and sequenced by both CID and ETD using data-dependent MS/MS. Statistically significant improvements in peptide identifications were observed with DMSO co-solvent. In order to understand this observation, we assessed the effects of supercharging reagents on the chromatographic separation and the electrospray quality. The increase in identifications was not due to supercharging, which was greater for the 0.1 % m-NBA co-solvent and not observed for the 5.0 % DMSO co-solvent. The improved MS/MS efficiency using the DMSO modified mobile phase appeared to result from charge state coalescence.

  16. Quaternary ammonium isobaric tag for a relative and absolute quantification of peptides.

    Science.gov (United States)

    Setner, Bartosz; Stefanowicz, Piotr; Szewczuk, Zbigniew

    2018-02-01

    Isobaric labeling quantification of peptides has become a method of choice for mass spectrometry-based proteomics studies. However, despite of wide variety of commercially available isobaric tags, none of the currently available methods offers significant improvement of sensitivity of detection during MS experiment. Recently, many strategies were applied to increase the ionization efficiency of peptides involving chemical modifications introducing quaternary ammonium fixed charge. Here, we present a novel quaternary ammonium-based isobaric tag for relative and absolute quantification of peptides (QAS-iTRAQ 2-plex). Upon collisional activation, the new stable benzylic-type cationic reporter ion is liberated from the tag. Deuterium atoms were used to offset the differential masses of a reporter group. We tested the applicability of QAS-iTRAQ 2-plex reagent on a series of model peptides as well as bovine serum albumin tryptic digest. Obtained results suggest usefulness of this isobaric ionization tag for relative and absolute quantification of peptides. Copyright © 2017 John Wiley & Sons, Ltd.

  17. Thiol-disulfide exchange in peptides derived from human growth hormone.

    Science.gov (United States)

    Chandrasekhar, Saradha; Epling, Daniel E; Sophocleous, Andreas M; Topp, Elizabeth M

    2014-04-01

    Disulfide bonds stabilize proteins by cross-linking distant regions into a compact three-dimensional structure. They can also participate in hydrolytic and oxidative pathways to form nonnative disulfide bonds and other reactive species. Such covalent modifications can contribute to protein aggregation. Here, we present experimental data for the mechanism of thiol-disulfide exchange in tryptic peptides derived from human growth hormone in aqueous solution. Reaction kinetics was monitored to investigate the effect of pH (6.0-10.0), temperature (4-50°C), oxidation suppressants [ethylenediaminetetraacetic acid (EDTA) and N2 sparging], and peptide secondary structure (amide cyclized vs. open form). The concentrations of free thiol containing peptides, scrambled disulfides, and native disulfide-linked peptides generated via thiol-disulfide exchange and oxidation reactions were determined using reverse-phase HPLC and liquid chromatography-mass spectrometry. Concentration versus time data were fitted to a mathematical model using nonlinear least squares regression analysis. At all pH values, the model was able to fit the data with R(2) ≥ 0.95. Excluding oxidation suppressants (EDTA and N2 sparging) resulted in an increase in the formation of scrambled disulfides via oxidative pathways but did not influence the intrinsic rate of thiol-disulfide exchange. In addition, peptide secondary structure was found to influence the rate of thiol-disulfide exchange. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  18. Identification of MHC class I H-2 Kb/Db-restricted immunogenic peptides derived from retinal proteins

    DEFF Research Database (Denmark)

    Wang, Mingjun; Bai, Fang; Pries, Mette

    2006-01-01

    PURPOSE: To identify H-2 Kb/Db-binding immunogenic peptides derived from retinal proteins. METHODS: Computer-based prediction was used to identify potentially H-2 Kb/Db-binding peptides derived from the interphotoreceptor retinol-binding protein (IRBP), soluble retinal antigen (S...... on day 21 after immunization with IRBP or IRBP and the immunogenic peptides. RESULTS: All the 21 predicted peptides were found to upregulate expression of H-2 Kb/Db on RMA-S cells. Five peptides, the two IRBP-derived peptides IRBP89-96 and IRBP(101-108), and the three PEDF-derived peptides, PEDF389....... The immunogenic peptides alone did not induce inflammation in the eyes, but they could enhance severity of uveitis induced by IRBP. CONCLUSIONS: Five of 21 H-2 Kb/Db-binding retinal protein-derived peptides were found to be immunogenic, suggesting that these peptides could function as autoantigenic epitopes...

  19. Production of Hypoallergenic Antibacterial Peptides from Defatted Soybean Meal in Membrane Bioreactor: A Bioprocess Engineering Study with Comprehensive Product Characterization

    Directory of Open Access Journals (Sweden)

    Arij it Nath

    2017-01-01

    Full Text Available Hypoallergenic antibacterial low-molecular-mass peptides were produced from defatted soybean meal in a membrane bioreactor. In the fi rst step, soybean meal proteins were digested with trypsin in the bioreactor, operated in batch mode. For the tryptic digestion of soybean meal protein, optimum initial soybean meal concentration of 75 g/L, temperature of 40 °C and pH=9.0 were determined. Aft er enzymatic digestion, low-molecular-mass peptides were purifi ed with cross-fl ow fl at sheet membrane (pore size 100 μm and then with tubular ceramic ultrafi ltration membrane (molecular mass cut-off 5 kDa. Eff ects of transmembrane pressure and the use of a static turbulence promoter to reduce the concentration polarization near the ultrafi ltration membrane surface were examined and their positive eff ects were proven. For the fi ltration with ultrafi ltration membrane, transmembrane pressure of 3•105 Pa with 3-stage discontinuous diafi ltration was found optimal. The molecular mass distribution of purifi ed peptides using ultrafi ltration membrane was determined by a liquid chromatography–electrospray ionization quadrupole time-of-fl ight mass spectrometry setup. More than 96 % of the peptides (calculated as relative frequency from the ultrafi ltration membrane permeate had the molecular mass M≤1.7 kDa and the highest molecular mass was found to be 3.1 kDa. The decrease of allergenic property due to the tryptic digestion and membrane fi ltration was determined by an enzyme-linked immunosorbent assay and it was found to exceed 99.9 %. It was also found that the peptides purifi ed in the ultrafi ltration membrane promoted the growth of Pediococcus acidilactici HA6111-2 and they possessed antibacterial activity against Bacillus cereus.

  20. Uranyl Oxalate Solubility

    Energy Technology Data Exchange (ETDEWEB)

    Leturcq, G.; Costenoble, S.; Grandjean, S. [CEA Marcoule DEN/DRCP/SCPS/LCA - BP17171 - 30207 Bagnols sur Ceze cedex (France)

    2008-07-01

    The solubility of uranyl oxalate was determined at ambient temperature by precipitation in oxalic-nitric solutions, using an initial uranyl concentration of 0.1 mol/L. Oxalic concentration varied from 0.075 to 0.3 mol/L while nitric concentration ranged between 0.75 and 3 mol/L. Dissolution tests, using complementary oxalic-nitric media, were carried out for 550 hours in order to study the kinetic to reach thermodynamic equilibrium. Similar solubility values were reached by dissolution and precipitation. Using the results, it was possible to draw the solubility surface versus oxalic and nitric concentrations and to determine both the apparent solubility constant of UO{sub 2}C{sub 2}O{sub 4}, 3H{sub 2}O (Ks) and the apparent formation constant of the first uranyl-oxalate complex UO{sub 2}C{sub 2}O{sub 4} (log {beta}1), for ionic strengths varying between 1 and 3 mol/L. Ks and log {beta}1 values were found to vary from 1.9 10{sup -8} to 9.2 10{sup -9} and from 5.95 to 6.06, respectively, when ionic strength varied from 1 to 3 mol/L. A second model may fit our data obtained at an ionic strength of 3 mol/L suggesting as reported by Moskvin et al. (1959) that no complexes are formed for [H{sup +}] at 3 M. The Ks value would then be 1.3 10{sup -8}. (authors)

  1. δ-Peptides from RuAAC-Derived 1,5-Disubstituted Triazole Units

    KAUST Repository

    Johansson, Johan R.; Hermansson, Elin; Nordé n, Bengt; Kann, Nina; Beke-Somfai, Tamá s

    2014-01-01

    of non-natural peptides composed of 1,5-disubstituted 1,2,3-triazole amino acids is presented. These peptides benefit from: a) modular synthesis of the monomers, allowing variation of the side chains; b) increased solubility of the oligomers in water

  2. Proteomic identification of Drosophila melanogaster male accessory gland proteins, including a pro-cathepsin and a soluble γ-glutamyl transpeptidase

    Directory of Open Access Journals (Sweden)

    Sajid Mohammed

    2006-05-01

    Full Text Available Background In Drosophila melanogaster, the male seminal fluid contains proteins that are important for reproductive success. Many of these proteins are synthesised by the male accessory glands and are secreted into the accessory gland lumen, where they are stored until required. Previous studies on the identification of Drosophila accessory gland products have largely focused on characterisation of male-specific accessory gland cDNAs from D. melanogaster and, more recently, Drosophila simulans. In the present study, we have used a proteomics approach without any sex bias to identify proteins in D. melanogaster accessory gland secretions. Results Thirteen secreted accessory gland proteins, including seven new accessory gland proteins, were identified by 2D-gel electrophoresis combined with mass spectrometry of tryptic fragments. They included protein-folding and stress-response proteins, a hormone, a lipase, a serpin, a cysteine-rich protein and two peptidases, a pro-enzyme form of a cathepsin K-like cysteine peptidase and a γ-glutamyl transpeptidase. Enzymatic studies established that accessory gland secretions contain a cysteine peptidase zymogen that can be activated at low pH. This peptidase may have a role in the processing of female and other male-derived proteins, but is unlikely to be involved in the processing of the sex peptide. γ-Glutamyl transpeptidases are type II integral membrane proteins; however, the identified AG γ-glutamyl transpeptidase (GGT-1 is unusual in that it is predicted to be a soluble secreted protein, a prediction that is supported by biochemical evidence. GGT-1 is possibly involved in maintaining a protective redox environment for sperm. The strong γ-glutamyl transpeptidase activity found in the secretions provides an explanation for the observation that glutamic acid is the most abundant free amino acid in accessory gland secretions of D. melanogaster. Conclusion We have applied biochemical approaches, not used

  3. Proteomic identification of Drosophila melanogaster male accessory gland proteins, including a pro-cathepsin and a soluble gamma-glutamyl transpeptidase.

    Science.gov (United States)

    Walker, Michael J; Rylett, Caroline M; Keen, Jeff N; Audsley, Neil; Sajid, Mohammed; Shirras, Alan D; Isaac, R Elwyn

    2006-05-02

    In Drosophila melanogaster, the male seminal fluid contains proteins that are important for reproductive success. Many of these proteins are synthesised by the male accessory glands and are secreted into the accessory gland lumen, where they are stored until required. Previous studies on the identification of Drosophila accessory gland products have largely focused on characterisation of male-specific accessory gland cDNAs from D. melanogaster and, more recently, Drosophila simulans. In the present study, we have used a proteomics approach without any sex bias to identify proteins in D. melanogaster accessory gland secretions. Thirteen secreted accessory gland proteins, including seven new accessory gland proteins, were identified by 2D-gel electrophoresis combined with mass spectrometry of tryptic fragments. They included protein-folding and stress-response proteins, a hormone, a lipase, a serpin, a cysteine-rich protein and two peptidases, a pro-enzyme form of a cathepsin K-like cysteine peptidase and a gamma-glutamyl transpeptidase. Enzymatic studies established that accessory gland secretions contain a cysteine peptidase zymogen that can be activated at low pH. This peptidase may have a role in the processing of female and other male-derived proteins, but is unlikely to be involved in the processing of the sex peptide. gamma-Glutamyl transpeptidases are type II integral membrane proteins; however, the identified AG gamma-glutamyl transpeptidase (GGT-1) is unusual in that it is predicted to be a soluble secreted protein, a prediction that is supported by biochemical evidence. GGT-1 is possibly involved in maintaining a protective redox environment for sperm. The strong gamma-glutamyl transpeptidase activity found in the secretions provides an explanation for the observation that glutamic acid is the most abundant free amino acid in accessory gland secretions of D. melanogaster. We have applied biochemical approaches, not used previously, to characterise

  4. Expression and Purification of Soluble STAT5b/STAT3 Proteins for SH2 Domain Binding Assay.

    Science.gov (United States)

    Asai, Akira; Takakuma, Kazuyuki

    2017-01-01

    When a large hydrophobic full-length protein is expressed in bacteria, it is often challenging to obtain recombinant proteins in the soluble fraction. One way to overcome this challenge is expression of deletion mutants that have improved solubility while maintaining biological activity. In this chapter, we describe a protocol for expression of truncated forms of STAT5b and STAT3 proteins that are soluble and retain SH2-mediated activity for phospho-Tyr peptide recognition.

  5. Simultaneous monitoring of oxidation, deamidation, isomerization, and glycosylation of monoclonal antibodies by liquid chromatography-mass spectrometry method with ultrafast tryptic digestion.

    Science.gov (United States)

    Wang, Yi; Li, Xiaojuan; Liu, Yan-Hui; Richardson, Daisy; Li, Huijuan; Shameem, Mohammed; Yang, Xiaoyu

    Monoclonal antibodies are subjected to a wide variety of post-translational modifications (PTMs) that cause structural heterogeneity. Characterization and control of these modifications or quality attributes are critical to ensure antibody quality and to define any potential effects on the ultimate safety and potency of antibody therapeutics. The biopharmaceutical industry currently uses numerous tools to analyze these quality attributes individually, which requires substantial time and resources. Here, we report a simple and ultrafast bottom-up liquid chromatography-mass spectrometry (uLC-MS) method with 5 min tryptic digestion to simultaneously analyze multiple modifications, including oxidation, deamidation, isomerization, glycation, glycosylation, and N-terminal pyro-glutamate formation, which can occur during antibody production in mammalian cell culture, during purification and/or on storage. Compared to commonly used preparation procedures, this uLC-MS method eliminates assay artifacts of falsely-increased Met oxidation, Asp isomerization, and Asn deamidation, a problem associated with long digestion times in conventional LC-MS methods. This simple, low artifact multi-attribute uLC-MS method can be used to quickly and accurately analyze samples at any stage of antibody drug development, in particular for clone and media selection during cell culture development.

  6. Preparation of open tubular capillary columns by in situ ring-opening polymerization and their applications in cLC-MS/MS analysis of tryptic digest.

    Science.gov (United States)

    Wang, Hongwei; Yao, Yating; Li, Ya; Ma, Shujuan; Peng, Xiaojun; Ou, Junjie; Ye, Mingliang

    2017-08-01

    An open tubular (OT) column (25 μm i.d.) was prepared by in situ ring-opening polymerization of octaglycidyldimethylsilyl polyhedral oligomeric silsesquioxanes (POSS-epoxy) with 4-aminophenyl disulfide (APDS) in a binary porogenic system of ethanol/H 2 O. It was found that porogenic composition played an important role in the formation of OT stationary phases. The ratio of ethanol/H 2 O at 6/1 (v/v) would lead to the fabrication of hybrid monoliths, while the ratio of ethanol/H 2 O at 13/1 (v/v) would result in the synthesis of OT phases. In addition, the effects of precursor content and reaction duration on the thickness of OT stationary phases were investigated. Either lower precursor content or shorter reaction duration would produce thinner layer of OT column. The repeatability of OT columns was evaluated through relative standard deviation (RSD%) with benzene as the analyte. The run-to-run, column-to-column and batch-to-batch repeatabilities were 1.7%, 4.8% and 5.6%, respectively, exhibiting satisfactory repeatability of the OT column. Then tryptic digest of mouse liver proteins was used to evaluate the performance of the resulting OT columns (25 μm i.d. × 2.5 m in length) by cLC-MS/MS analysis, demonstrating their potential in proteome analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Argon solubility in liquid steel

    NARCIS (Netherlands)

    Boom, R; Dankert, O; Van Veen, A; Kamperman, AA

    2000-01-01

    Experiments have been performed to establish the solubility of argon in liquid interstitial-free steel. The solubility appears to be lower than 0.1 at ppb, The results are in line with argon solubilities reported in the literature on liquid iron. Semiempirical theories and calculations based on the

  8. UniNovo: a universal tool for de novo peptide sequencing.

    Science.gov (United States)

    Jeong, Kyowon; Kim, Sangtae; Pevzner, Pavel A

    2013-08-15

    Mass spectrometry (MS) instruments and experimental protocols are rapidly advancing, but de novo peptide sequencing algorithms to analyze tandem mass (MS/MS) spectra are lagging behind. Although existing de novo sequencing tools perform well on certain types of spectra [e.g. Collision Induced Dissociation (CID) spectra of tryptic peptides], their performance often deteriorates on other types of spectra, such as Electron Transfer Dissociation (ETD), Higher-energy Collisional Dissociation (HCD) spectra or spectra of non-tryptic digests. Thus, rather than developing a new algorithm for each type of spectra, we develop a universal de novo sequencing algorithm called UniNovo that works well for all types of spectra or even for spectral pairs (e.g. CID/ETD spectral pairs). UniNovo uses an improved scoring function that captures the dependences between different ion types, where such dependencies are learned automatically using a modified offset frequency function. The performance of UniNovo is compared with PepNovo+, PEAKS and pNovo using various types of spectra. The results show that the performance of UniNovo is superior to other tools for ETD spectra and superior or comparable with others for CID and HCD spectra. UniNovo also estimates the probability that each reported reconstruction is correct, using simple statistics that are readily obtained from a small training dataset. We demonstrate that the estimation is accurate for all tested types of spectra (including CID, HCD, ETD, CID/ETD and HCD/ETD spectra of trypsin, LysC or AspN digested peptides). UniNovo is implemented in JAVA and tested on Windows, Ubuntu and OS X machines. UniNovo is available at http://proteomics.ucsd.edu/Software/UniNovo.html along with the manual.

  9. PeptideAtlas

    Data.gov (United States)

    U.S. Department of Health & Human Services — PeptideAtlas is a multi-organism, publicly accessible compendium of peptides identified in a large set of tandem mass spectrometry proteomics experiments. Mass...

  10. Peptide-Carrier Conjugation

    DEFF Research Database (Denmark)

    Hansen, Paul Robert

    2015-01-01

    To produce antibodies against synthetic peptides it is necessary to couple them to a protein carrier. This chapter provides a nonspecialist overview of peptide-carrier conjugation. Furthermore, a protocol for coupling cysteine-containing peptides to bovine serum albumin is outlined....

  11. PH dependent adhesive peptides

    Science.gov (United States)

    Tomich, John; Iwamoto, Takeo; Shen, Xinchun; Sun, Xiuzhi Susan

    2010-06-29

    A novel peptide adhesive motif is described that requires no receptor or cross-links to achieve maximal adhesive strength. Several peptides with different degrees of adhesive strength have been designed and synthesized using solid phase chemistries. All peptides contain a common hydrophobic core sequence flanked by positively or negatively charged amino acids sequences.

  12. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2003-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  13. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  14. Peptide Nucleic Acids (PNA)

    DEFF Research Database (Denmark)

    2002-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  15. Peptide Nucleic Acid Synthons

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  16. Antimicrobial Peptides in 2014

    Directory of Open Access Journals (Sweden)

    Guangshun Wang

    2015-03-01

    Full Text Available This article highlights new members, novel mechanisms of action, new functions, and interesting applications of antimicrobial peptides reported in 2014. As of December 2014, over 100 new peptides were registered into the Antimicrobial Peptide Database, increasing the total number of entries to 2493. Unique antimicrobial peptides have been identified from marine bacteria, fungi, and plants. Environmental conditions clearly influence peptide activity or function. Human α-defensin HD-6 is only antimicrobial under reduced conditions. The pH-dependent oligomerization of human cathelicidin LL-37 is linked to double-stranded RNA delivery to endosomes, where the acidic pH triggers the dissociation of the peptide aggregate to release its cargo. Proline-rich peptides, previously known to bind to heat shock proteins, are shown to inhibit protein synthesis. A model antimicrobial peptide is demonstrated to have multiple hits on bacteria, including surface protein delocalization. While cell surface modification to decrease cationic peptide binding is a recognized resistance mechanism for pathogenic bacteria, it is also used as a survival strategy for commensal bacteria. The year 2014 also witnessed continued efforts in exploiting potential applications of antimicrobial peptides. We highlight 3D structure-based design of peptide antimicrobials and vaccines, surface coating, delivery systems, and microbial detection devices involving antimicrobial peptides. The 2014 results also support that combination therapy is preferred over monotherapy in treating biofilms.

  17. Soluble porphyrin polymers

    Science.gov (United States)

    Gust, Jr., John Devens; Liddell, Paul Anthony

    2015-07-07

    Porphyrin polymers of Structure 1, where n is an integer (e.g., 1, 2, 3, 4, 5, or greater) ##STR00001## are synthesized by the method shown in FIGS. 2A and 2B. The porphyrin polymers of Structure 1 are soluble in organic solvents such as 2-MeTHF and the like, and can be synthesized in bulk (i.e., in processes other than electropolymerization). These porphyrin polymers have long excited state lifetimes, making the material suitable as an organic semiconductor for organic electronic devices including transistors and memories, as well as solar cells, sensors, light-emitting devices, and other opto-electronic devices.

  18. Rapid micro-scale proteolysis of proteins for MALDI-MS peptide mapping using immobilized trypsin

    Science.gov (United States)

    Gobom, Johan; Nordhoff, Eckhard; Ekman, Rolf; Roepstorff, Peter

    1997-12-01

    In this study we present a rapid method for tryptic digestion of proteins using micro-columns with enzyme immobilized on perfusion chromatography media. The performance of the method is exemplified with acyl-CoA-binding protein and reduced carbamidomethylated bovine serum albumin. The method proved to be significantly faster and yielded a better sequence coverage and an improved signal-to-noise ratio for the MALDI-MS peptide maps, compared to in-solution- and on-target digestion. Only a single sample transfer step is required, and therefore sample loss due to adsorption to surfaces is reduced, which is a critical issue when handling low picomole to femtomole amounts of proteins. An example is shown with on-column proteolytic digestion and subsequent elution of the digest into a reversed-phase micro-column. This is useful if the sample contains large amounts of salt or is too diluted for MALDI-MS analysis. Furthermore, by step-wise elution from the reversedphase column, a complex digest can be fractionated, which reduces signal suppression and facilitates data interpretation in the subsequent MS-analysis. The method also proved useful for consecutive digestions with enzymes of different cleavage specificity. This is exemplified with on-column tryptic digestion, followed by reversed-phase step-wise elution, and subsequent on-target V8 protease digestion.

  19. Efeito do pH e da hidrólise tríptica sobre as propriedades emulsionantes da globina bovina The effect of the pH and the tryptic hydrolysis on the emulsifying properties of bovine globin

    Directory of Open Access Journals (Sweden)

    Cleia Batista Dias ORNELLAS

    2001-01-01

    Full Text Available No intuito de estudar o efeito do pH e da ação da tripsina sobre as propriedades emulsionantes da globina bovina, extraída pelo método da acetona acidificada, foram determinados neste trabalho, a capacidade emulsionante (EC, o índice de atividade emulsionante (EAI e a estabilidade da emulsão (ES. Testaram-se os valores de pH de 3,0 a 8,0 e os tempos de hidrólise de 5,0 a 60 min. Os dados obtidos indicam que os maiores valores de EC e ES foram obtidos no pH 5,0 e 6,0, respectivamente, correspondente à faixa de alta solubilidade da proteína. Por outro lado, o EAI, além de apresentar um máximo no pH 3,0, foi igualmente elevado nos valores de pH 7,0 e 8,0, situados na zona onde a globina é praticamente insolúvel. A hidrólise tríptica, nas condições empregadas, contribuiu para melhorar a EC, em toda a faixa de pH estudada, enquanto que para o EAI somente foi benéfico em pH 4,0 e 5,0. No caso da ES, este tratamento enzimático não foi vantajoso, promovendo melhoras apenas no pH 7,0, onde a proteína é insolúvel, e somente após 60 min de hidrólise.The effect of the pH and of the trypsin on the emulsifying properties of bovine globin, extracted by the acidified acetone method, was studied. The emulsifying capacity (EC, the emulsifying activity index (EAI and the emulsion stability (ES were determined at pH varying from 3.0 to 8.0 and employing hydrolysis times from 5 to 60 min. The highest vaules for EC and ES were obtained at pH 5.0 and 6.0, respectively, corresponding to the range of large protein solubility. On the other hand, the EAI was higher at pH 3.0 and also at pH 7.0 and 8.0, where the protein is insoluble. The tryptic hydrolysis produced an increase in EC, in all pH ranges studied, while for the EAI the same effect was observed only in pH 4.0 and 5.0, and for ES at pH 7.0 after 60 min of hydrolysis.

  20. EThcD Discrimination of Isomeric Leucine/Isoleucine Residues in Sequencing of the Intact Skin Frog Peptides with Intramolecular Disulfide Bond

    Science.gov (United States)

    Samgina, Tatiana Yu; Kovalev, Sergey V.; Tolpina, Miriam D.; Trebse, Polonca; Torkar, Gregor; Lebedev, Albert T.

    2018-05-01

    Our scientific interests involve de novo sequencing of non-tryptic natural amphibian skin peptides including those with intramolecular S-S bond by means of exclusively mass spectrometry. Reliable discrimination of the isomeric leucine/isoleucine residues during peptide sequencing by means of mass spectrometry represents a bottleneck in the workflow for complete automation of the primary structure elucidation of these compounds. MS3 is capable of solving the problem. Earlier we demonstrated the advanced efficiency of ETD-HCD method to discriminate Leu/Ile in individual peptides by consecutive application of ETD to the polyprotonated peptides followed by HCD applied to the manually selected primary z-ions with the targeted isomeric residues at their N-termini and registration of the characteristic w-ions. Later this approach was extended to deal with several (4-7) broad band mass ranges, without special isolation of the primary z-ions. The present paper demonstrates an advanced version of this method when EThcD is applied in the whole mass range to a complex mixture of natural non-tryptic peptides without their separation and intermediate isolation of the targeted z-ions. The proposed EThcD method showed over 81% efficiency for the large natural peptides with intact disulfide ring, while the interfering process of radical site migration is suppressed. Due to higher speed and sensitivity, the proposed EThcD approach facilitates the analytical procedure and allows for the automation of the entire experiment and data processing. Moreover, in some cases it gives a chance to establish the nature of the residues in the intact intramolecular disulfide loops. [Figure not available: see fulltext.

  1. A 19-kDa C-terminal tryptic fragment of the α chain of Na/K-ATPase is essential for occlusion and transport of cations

    International Nuclear Information System (INIS)

    Karlish, S.J.D.; Goldshleger, R.; Stein, W.D.

    1990-01-01

    Tryptic digestion of pig renal Na/K-ATPase in the presence of Rb and absence of Ca ions removes about half of the protein but leaves a stable 19-kDa membrane-embedded fragment derived from the α chain, a largely intact β chain, and essentially normal Rb- and Na-occlusion capacity. Subsequent digestion with trypsin in the presence of Ca or absence of Rb ions leads to rapid loss of the 19-kDa fragment and a parallel loss of Rb occlusion, demonstrating that the fragment is essential for occlusion. The N-terminal sequence of the 19-kDa fragment is Asn-Pro-Lys-Thr-Asp-Lys-Leu-Val-Asn-Glu-Arg-Leu-Ile-Ser-Met-Ala, beginning at residue 830 and extending toward the C terminus. Membranes containing the 19-kDa fragment have the following functional properties. (i) ATP-dependent functions are absent. (ii) The apparent affinity for occluding Rb is unchanged, the affinity for Na is lower than in the control enzyme, and activation is now strongly sigmoidal rather than hyperbolic. (iii) Membranes containing the 19-kDa fragment can be reconstituted into phospholipid vesicles and sustain slow Rb-Rb exchange. Thus the transport pathway is retained. The authors conclude that cation occlusion sites and the transport pathway within transmembrane segments are quite separate from the ATP binding sites, located on the cytoplasmic domain of the α chain. Interactions between cation and ATP sites, the heart of active transport, must be indirect - mediated, presumably, by conformational changes of the protein

  2. A 19-kDa C-terminal tryptic fragment of the. alpha. chain of Na/K-ATPase is essential for occlusion and transport of cations

    Energy Technology Data Exchange (ETDEWEB)

    Karlish, S.J.D.; Goldshleger, R. (Weizmann Institute of Science, Rehovot (Israel)); Stein, W.D. (Hebrew Univ. Jerusalem (Israel))

    1990-06-01

    Tryptic digestion of pig renal Na/K-ATPase in the presence of Rb and absence of Ca ions removes about half of the protein but leaves a stable 19-kDa membrane-embedded fragment derived from the {alpha} chain, a largely intact {beta} chain, and essentially normal Rb- and Na-occlusion capacity. Subsequent digestion with trypsin in the presence of Ca or absence of Rb ions leads to rapid loss of the 19-kDa fragment and a parallel loss of Rb occlusion, demonstrating that the fragment is essential for occlusion. The N-terminal sequence of the 19-kDa fragment is Asn-Pro-Lys-Thr-Asp-Lys-Leu-Val-Asn-Glu-Arg-Leu-Ile-Ser-Met-Ala, beginning at residue 830 and extending toward the C terminus. Membranes containing the 19-kDa fragment have the following functional properties. (i) ATP-dependent functions are absent. (ii) The apparent affinity for occluding Rb is unchanged, the affinity for Na is lower than in the control enzyme, and activation is now strongly sigmoidal rather than hyperbolic. (iii) Membranes containing the 19-kDa fragment can be reconstituted into phospholipid vesicles and sustain slow Rb-Rb exchange. Thus the transport pathway is retained. The authors conclude that cation occlusion sites and the transport pathway within transmembrane segments are quite separate from the ATP binding sites, located on the cytoplasmic domain of the {alpha} chain. Interactions between cation and ATP sites, the heart of active transport, must be indirect - mediated, presumably, by conformational changes of the protein.

  3. Development of a dedicated peptide tandem mass spectral library for conservation science.

    Science.gov (United States)

    Fremout, Wim; Dhaenens, Maarten; Saverwyns, Steven; Sanyova, Jana; Vandenabeele, Peter; Deforce, Dieter; Moens, Luc

    2012-05-30

    In recent years, the use of liquid chromatography tandem mass spectrometry (LC-MS/MS) on tryptic digests of cultural heritage objects has attracted much attention. It allows for unambiguous identification of peptides and proteins, and even in complex mixtures species-specific identification becomes feasible with minimal sample consumption. Determination of the peptides is commonly based on theoretical cleavage of known protein sequences and on comparison of the expected peptide fragments with those found in the MS/MS spectra. In this approach, complex computer programs, such as Mascot, perform well identifying known proteins, but fail when protein sequences are unknown or incomplete. Often, when trying to distinguish evolutionarily well preserved collagens of different species, Mascot lacks the required specificity. Complementary and often more accurate information on the proteins can be obtained using a reference library of MS/MS spectra of species-specific peptides. Therefore, a library dedicated to various sources of proteins in works of art was set up, with an initial focus on collagen rich materials. This paper discusses the construction and the advantages of this spectral library for conservation science, and its application on a number of samples from historical works of art. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Selective enrichment and separation of phosphotyrosine peptides by thermosensitive molecularly imprinted polymers.

    Science.gov (United States)

    Yang, Xiaoqing; Xia, Yan

    2016-01-01

    Novel thermosensitive molecularly imprinted polymers were successfully prepared using the epitope imprinting approach in the presence of the mimic template phenylphosphonic acid, the functional monomer vinylphosphonic acid-Ti(4+) , the temperature-sensitive monomer N-isopropylacrylamide and the crosslinker N,N'-methylenebisacrylamide. The ratio of the template/thermosensitive monomers/crosslinker was optimized, and when the ratio was 2:2:1, the prepared thermosensitive molecularly imprinted polymers had the highest imprinting factor. The synthetic thermosensitive molecularly imprinted polymers were characterized by Fourier transform infrared spectroscopy to reveal the combination and elution processes of the template. Then, the adsorption capacity and thermosensitivity was measured. When the temperature was 28°C, the imprinting factor was the highest. The selectivity and adsorption capacity of the thermosensitive molecularly imprinted polymers for phosphotyrosine peptides from a mixture of three tailor-made peptides were measured by high-performance liquid chromatography. The results showed that the thermosensitive molecularly imprinted polymers have good selectivity for phosphotyrosine peptides. Finally, the imprinted hydrogels were applied to specifically adsorb phosphotyrosine peptides from a sample mixture containing phosphotyrosine and a tryptic digest of β-casein, which demonstrated high selectivity. After four rebinding cycles, 78.9% adsorption efficiency was still retained. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Transmembrane transport of peptide type compounds: prospects for oral delivery

    Science.gov (United States)

    Lipka, E.; Crison, J.; Amidon, G. L.

    1996-01-01

    Synthesis and delivery of potential therapeutic peptides and peptidomimetic compounds has been the focus of intense research over the last 10 years. While it is widely recognized that numerous limitations apply to oral delivery of peptides, some of the limiting factors have been addressed and their mechanisms elucidated, which has lead to promising strategies. This article will briefly summarize the challenges, results and current approaches of oral peptide delivery and give some insight on future strategies. The barriers determining peptide bioavailability after oral administration are intestinal membrane permability, size limitations, intestinal and hepatic metabolism and in some cases solubility limitations. Poor membrane permeabilities of hydrophilic peptides might be overcome by structurally modifying the compounds, thus increasing their membrane partition characteristics and/or their affinity to carrier proteins. Another approach is the site-specific delivery of the peptide to the most permeable parts of the intestine. The current view on size limitation for oral drug delivery has neglected partition considerations. Recent studies suggest that compounds with a molecular weight up to 4000 might be significantly absorbed, assuming appropriate partition behavior and stability. Metabolism, probably the most significant factor in the absorption fate of peptides, might be controlled by coadministration of competitive enzyme inhibitors, structural modifications and administration of the compound as a well absorbed prodrug that is converted into the therapeutically active agent after its absorption. For some peptides poor solubility might present a limitation to oral absorption, an issue that has been addressed by mechanistically defining and therefore improving formulation parameters. Effective oral peptide delivery requires further development in understanding these complex mechanisms in order to maximize the therapeutic potential of this class of compounds.

  6. Sensory and chromatographic evaluations of water soluble fractions from air-dried sausages

    DEFF Research Database (Denmark)

    Henriksen, Anders Peter; Stahnke, Marie Louise Heller

    1997-01-01

    Low molecular weight water soluble compounds were extracted from Danish salami, Italian sausage, and Spanish Chorizo. The extracts were fractionated by gel filtration chromatography revealing peptides with a molecular weight less than 4200 Dalton. Fractions consisting of smaller peptides and free...... amino acids had enhanced savory taste impressions described as mainly bouillon, bitter, sour, salty and plastic with odor notes of boiled potato. Determination of amino acids in the fractions before and after hydrolysis revealed the presence of mainly hydrophilic peptides in all fractions. Partial least...

  7. Peptide and protein delivery using new drug delivery systems.

    Science.gov (United States)

    Jain, Ashish; Jain, Aviral; Gulbake, Arvind; Shilpi, Satish; Hurkat, Pooja; Jain, Sanjay K

    2013-01-01

    Pharmaceutical and biotechnological research sorts protein drug delivery systems by importance based on their various therapeutic applications. The effective and potent action of the proteins/peptides makes them the drugs of choice for the treatment of numerous diseases. Major research issues in protein delivery include the stabilization of proteins in delivery devices and the design of appropriate target-specific protein carriers. Many efforts have been made for effective delivery of proteins/peptidal drugs through various routes of administrations for successful therapeutic effects. Nanoparticles made of biodegradable polymers such as poly lactic acid, polycaprolactone, poly(lactic-co-glycolic acid), the poly(fumaric-co-sebacic) anhydride chitosan, and modified chitosan, as well as solid lipids, have shown great potential in the delivery of proteins/peptidal drugs. Moreover, scientists also have used liposomes, PEGylated liposomes, niosomes, and aquasomes, among others, for peptidal drug delivery. They also have developed hydrogels and transdermal drug delivery systems for peptidal drug delivery. A receptor-mediated delivery system is another attractive strategy to overcome the limitation in drug absorption that enables the transcytosis of the protein across the epithelial barrier. Modification such as PEGnology is applied to various proteins and peptides of the desired protein and peptides also increases the circulating life, solubility and stability, pharmacokinetic properties, and antigenicity of protein. This review focuses on various approaches for effective protein/peptidal drug delivery, with special emphasis on insulin delivery.

  8. [Plant signaling peptides. Cysteine-rich peptides].

    Science.gov (United States)

    Ostrowski, Maciej; Kowalczyk, Stanisław

    2015-01-01

    Recent bioinformatic and genetic analyses of several model plant genomes have revealed the existence of a highly abundant group of signaling peptides that are defined as cysteine-rich peptides (CRPs). CRPs are usually in size between 50 and 90 amino acid residues, they are positively charged, and they contain 4-16 cysteine residues that are important for the correct conformational folding. Despite the structural differences among CRP classes, members from each class have striking similarities in their molecular properties and function. The present review presents the recent progress in research on signaling peptides from several families including: EPF/EPFL, SP11/SCR, PrsS, RALF, LURE, and some other peptides belonging to CRP group. There is convincing evidence indicating multiple roles for these CRPs as signaling molecules during the plant life cycle, ranging from stomata development and patterning, self-incompatibility, pollen tube growth and guidance, reproductive processes, and nodule formation.

  9. Water-soluble vitamins.

    Science.gov (United States)

    Konings, Erik J M

    2006-01-01

    Simultaneous Determination of Vitamins.--Klejdus et al. described a simultaneous determination of 10 water- and 10 fat-soluble vitamins in pharmaceutical preparations by liquid chromatography-diode-array detection (LC-DAD). A combined isocratic and linear gradient allowed separation of vitamins in 3 distinct groups: polar, low-polar, and nonpolar. The method was applied to pharmaceutical preparations, fortified powdered drinks, and food samples, for which results were in good agreement with values claimed. Heudi et al. described a separation of 9 water-soluble vitamins by LC-UV. The method was applied for the quantification of vitamins in polyvitaminated premixes used for the fortification of infant nutrition products. The repeatability of the method was evaluated at different concentration levels and coefficients of variation were based on, for example, LC. Koontz et al. showed results of total folate concentrations measured by microbiological assay in a variety of foods. Samples were submitted in a routine manner to experienced laboratories that regularly perform folate analysis fee-for-service basis in the United States. Each laboratory reported the use of a microbiological method similar to the AOAC Official Method for the determination of folic acid. Striking was, the use of 3 different pH extraction conditions by 4 laboratories. Only one laboratory reported using a tri-enzyme extraction. Results were evaluated. Results for folic acid fortified foods had considerably lower between-laboratory variation, 9-11%, versus >45% for other foods. Mean total folate ranged from 14 to 279 microg/100 g for a mixed vegetable reference material, from 5 to 70 microg/100 g for strawberries, and from 28 to 81 microg/100 g for wholemeal flour. One should realize a large variation in results, which might be caused by slight modifications in the microbiological analysis of total folate in foods or the analysis in various (unfortified) food matrixes. Furthermore, optimal

  10. Water-Soluble Dried Blood Spot in Protein Analysis: A Proof-of-Concept Study.

    Science.gov (United States)

    Rosting, Cecilie; Gjelstad, Astrid; Halvorsen, Trine Grønhaug

    2015-08-04

    In the present work human chorionic gonadotropin (hCG) was used as a model protein in a proof-of-concept study combining water-soluble dried blood spot (DBS) material in liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based protein analysis. A water-soluble material consisting of commercially available carboxymethyl cellulose (CMC) was evaluated as sampling material for this purpose. The material dissolved readily at physiological pH. Different sample preparation methods were evaluated, and in the final method, 15 μL of whole blood was deposited and dried on CMC before the whole spot was dissolved prior to cleanup by immunoaffinity extraction, tryptic digest, and preconcentration by solid-phase extraction (SPE). The results indicated complete dissolution of hCG from the spots, acceptable limit of detection (LOD) (0.1 IU/mL), linearity (R(2) = 0.959), accuracy (16%), and precision (≤22%). Long-term stability (45 days) of hCG in dried spots at reduced temperatures (≤8 °C) was also demonstrated. The analyte recovery was comparable to the commercially available nonsolvable cellulose material (FTA DMPK-C card).

  11. Peptides in melanoma therapy.

    Science.gov (United States)

    Mocellin, Simone

    2012-01-01

    Peptides derived from tumor associated antigens can be utilized to elicit a therapeutically effective immune response against melanoma in experimental models. However, patient vaccination with peptides - although it is often followed by the induction of melanoma- specific T lymphocytes - is rarely associated with tumor response of clinical relevance. In this review I summarize the principles of peptide design as well as the results so far obtained in the clinical setting while treating cutaneous melanoma by means of this active immunotherapy strategy. I also discuss some immunological and methodological issues that might be helpful for the successful development of peptide-based vaccines.

  12. Antimicrobial Peptides in Reptiles

    Science.gov (United States)

    van Hoek, Monique L.

    2014-01-01

    Reptiles are among the oldest known amniotes and are highly diverse in their morphology and ecological niches. These animals have an evolutionarily ancient innate-immune system that is of great interest to scientists trying to identify new and useful antimicrobial peptides. Significant work in the last decade in the fields of biochemistry, proteomics and genomics has begun to reveal the complexity of reptilian antimicrobial peptides. Here, the current knowledge about antimicrobial peptides in reptiles is reviewed, with specific examples in each of the four orders: Testudines (turtles and tortosises), Sphenodontia (tuataras), Squamata (snakes and lizards), and Crocodilia (crocodilans). Examples are presented of the major classes of antimicrobial peptides expressed by reptiles including defensins, cathelicidins, liver-expressed peptides (hepcidin and LEAP-2), lysozyme, crotamine, and others. Some of these peptides have been identified and tested for their antibacterial or antiviral activity; others are only predicted as possible genes from genomic sequencing. Bioinformatic analysis of the reptile genomes is presented, revealing many predicted candidate antimicrobial peptides genes across this diverse class. The study of how these ancient creatures use antimicrobial peptides within their innate immune systems may reveal new understandings of our mammalian innate immune system and may also provide new and powerful antimicrobial peptides as scaffolds for potential therapeutic development. PMID:24918867

  13. Students’ misconceptions on solubility equilibrium

    Science.gov (United States)

    Setiowati, H.; Utomo, S. B.; Ashadi

    2018-05-01

    This study investigated the students’ misconceptions of the solubility equilibrium. The participants of the study consisted of 164 students who were in the science class of second year high school. Instrument used is two-tier diagnostic test consisting of 15 items. Responses were marked and coded into four categories: understanding, misconception, understand little without misconception, and not understanding. Semi-structured interviews were carried out with 45 students according to their written responses which reflected different perspectives, to obtain a more elaborated source of data. Data collected from multiple methods were analyzed qualitatively and quantitatively. Based on the data analysis showed that the students misconceptions in all areas in solubility equilibrium. They had more misconceptions such as in the relation of solubility and solubility product, common-ion effect and pH in solubility, and precipitation concept.

  14. On the americium oxalate solubility

    International Nuclear Information System (INIS)

    Zakolupin, S.A.; Korablin, Eh.V.

    1977-01-01

    The americium oxalate solubility at different nitric (0.0-1 M) and oxalic (0.0-0.4 M) acid concentrations was investigated in the temperature range from 14 to 60 deg C. The dependence of americium oxalate solubility on the oxalic acid concentration was determined. Increasing oxalic acid concentration was found to reduce the americium oxalate solubility. The dependence of americium oxalate solubility on the oxalic acid concentration was noted to be a minimum at low acidity (0.1-0.3 M nitric acid). This is most likely due to Am(C 2 O 4 ) + , Am(C 2 O 4 ) 2 - and Am(C 2 O 4 ) 3 3- complex ion formation which have different unstability constants. On the basis of the data obtained, a preliminary estimate was carried out for the product of americium oxalate solubility in nitric acid medium (10 -29 -10 -31 ) and of the one in water (6.4x10 -20 )

  15. Insulin C-peptide test

    Science.gov (United States)

    C-peptide ... the test depends on the reason for the C-peptide measurement. Ask your health care provider if ... C-peptide is measured to tell the difference between insulin the body produces and insulin someone injects ...

  16. Two-dimensional high-performance thin-layer chromatography of tryptic bovine albumin digest using normal- and reverse-phase systems with silanized silica stationary phase.

    Science.gov (United States)

    Gwarda, Radosław Łukasz; Dzido, Tadeusz Henryk

    2013-10-18

    Among many advantages of planar techniques, two-dimensional (2D) separation seems to be the most important for analysis of complex samples. Here we present quick, simple and efficient two-dimensional high-performance thin-layer chromatography (2D HPTLC) of bovine albumin digest using commercial HPTLC RP-18W plates (silica based stationary phase with chemically bonded octadecyl ligands of coverage density 0.5μmol/m(2) from Merck, Darmstadt). We show, that at low or high concentration of water in the mobile phase comprised methanol and some additives the chromatographic systems with the plates mentioned demonstrate normal- or reversed-phase liquid chromatography properties, respectively, for separation of peptides obtained. These two systems show quite different separation selectivity and their combination into 2D HPTLC process provides excellent separation of peptides of the bovine albumin digest. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Uranium solubility and solubility controls in selected Needle's Eye groundwaters

    International Nuclear Information System (INIS)

    Falck, W.E.; Hooker, P.J.

    1991-01-01

    The solubility control of uranium in selected groundwater samples from the cliff and sediments at the Needle's Eye natural analogue site is investigated using the speciation code PHREEQE and the CHEMVAL thermodynamic database (release 3). Alkali-earth bearing uranyl carbonate secondary minerals are likely to exert influence on the solubility . Other candidates are UO 2 and arsenates, depending on the prevailing redox conditions. In the absence of literature data, solubility products for important arsenates have been estimated from analogy with other arsenates and phosphates. Phosphates themselves are unlikely to exert control owing to their comparatively high solubilities. The influence of seawater flooding into the sediments is also discussed. The importance of uranyl arsenates in the retardation of uranium in shallow sediments has been demonstrated in theory, but there are some significant gaps in the thermodynamic databases used. (author)

  18. Peptide Vaccines for Leishmaniasis

    Directory of Open Access Journals (Sweden)

    Rory C. F. De Brito

    2018-05-01

    Full Text Available Due to an increase in the incidence of leishmaniases worldwide, the development of new strategies such as prophylactic vaccines to prevent infection and decrease the disease have become a high priority. Classic vaccines against leishmaniases were based on live or attenuated parasites or their subunits. Nevertheless, the use of whole parasite or their subunits for vaccine production has numerous disadvantages. Therefore, the use of Leishmania peptides to design more specific vaccines against leishmaniases seems promising. Moreover, peptides have several benefits in comparison with other kinds of antigens, for instance, good stability, absence of potentially damaging materials, antigen low complexity, and low-cost to scale up. By contrast, peptides are poor immunogenic alone, and they need to be delivered correctly. In this context, several approaches described in this review are useful to solve these drawbacks. Approaches, such as, peptides in combination with potent adjuvants, cellular vaccinations, adenovirus, polyepitopes, or DNA vaccines have been used to develop peptide-based vaccines. Recent advancements in peptide vaccine design, chimeric, or polypeptide vaccines and nanovaccines based on particles attached or formulated with antigenic components or peptides have been increasingly employed to drive a specific immune response. In this review, we briefly summarize the old, current, and future stands on peptide-based vaccines, describing the disadvantages and benefits associated with them. We also propose possible approaches to overcome the related weaknesses of synthetic vaccines and suggest future guidelines for their development.

  19. Peptide Vaccines for Leishmaniasis.

    Science.gov (United States)

    De Brito, Rory C F; Cardoso, Jamille M De O; Reis, Levi E S; Vieira, Joao F; Mathias, Fernando A S; Roatt, Bruno M; Aguiar-Soares, Rodrigo Dian D O; Ruiz, Jeronimo C; Resende, Daniela de M; Reis, Alexandre B

    2018-01-01

    Due to an increase in the incidence of leishmaniases worldwide, the development of new strategies such as prophylactic vaccines to prevent infection and decrease the disease have become a high priority. Classic vaccines against leishmaniases were based on live or attenuated parasites or their subunits. Nevertheless, the use of whole parasite or their subunits for vaccine production has numerous disadvantages. Therefore, the use of Leishmania peptides to design more specific vaccines against leishmaniases seems promising. Moreover, peptides have several benefits in comparison with other kinds of antigens, for instance, good stability, absence of potentially damaging materials, antigen low complexity, and low-cost to scale up. By contrast, peptides are poor immunogenic alone, and they need to be delivered correctly. In this context, several approaches described in this review are useful to solve these drawbacks. Approaches, such as, peptides in combination with potent adjuvants, cellular vaccinations, adenovirus, polyepitopes, or DNA vaccines have been used to develop peptide-based vaccines. Recent advancements in peptide vaccine design, chimeric, or polypeptide vaccines and nanovaccines based on particles attached or formulated with antigenic components or peptides have been increasingly employed to drive a specific immune response. In this review, we briefly summarize the old, current, and future stands on peptide-based vaccines, describing the disadvantages and benefits associated with them. We also propose possible approaches to overcome the related weaknesses of synthetic vaccines and suggest future guidelines for their development.

  20. Interplay between Peptide Bond Geometrical Parameters in Nonglobular Structural Contexts

    Directory of Open Access Journals (Sweden)

    Luciana Esposito

    2013-01-01

    Full Text Available Several investigations performed in the last two decades have unveiled that geometrical parameters of protein backbone show a remarkable variability. Although these studies have provided interesting insights into one of the basic aspects of protein structure, they have been conducted on globular and water-soluble proteins. We report here a detailed analysis of backbone geometrical parameters in nonglobular proteins/peptides. We considered membrane proteins and two distinct fibrous systems (amyloid-forming and collagen-like peptides. Present data show that in these systems the local conformation plays a major role in dictating the amplitude of the bond angle N-Cα-C and the propensity of the peptide bond to adopt planar/nonplanar states. Since the trends detected here are in line with the concept of the mutual influence of local geometry and conformation previously established for globular and water-soluble proteins, our analysis demonstrates that the interplay of backbone geometrical parameters is an intrinsic and general property of protein/peptide structures that is preserved also in nonglobular contexts. For amyloid-forming peptides significant distortions of the N-Cα-C bond angle, indicative of sterical hidden strain, may occur in correspondence with side chain interdigitation. The correlation between the dihedral angles Δω/ψ in collagen-like models may have interesting implications for triple helix stability.

  1. Interplay between peptide bond geometrical parameters in nonglobular structural contexts.

    Science.gov (United States)

    Esposito, Luciana; Balasco, Nicole; De Simone, Alfonso; Berisio, Rita; Vitagliano, Luigi

    2013-01-01

    Several investigations performed in the last two decades have unveiled that geometrical parameters of protein backbone show a remarkable variability. Although these studies have provided interesting insights into one of the basic aspects of protein structure, they have been conducted on globular and water-soluble proteins. We report here a detailed analysis of backbone geometrical parameters in nonglobular proteins/peptides. We considered membrane proteins and two distinct fibrous systems (amyloid-forming and collagen-like peptides). Present data show that in these systems the local conformation plays a major role in dictating the amplitude of the bond angle N-C(α)-C and the propensity of the peptide bond to adopt planar/nonplanar states. Since the trends detected here are in line with the concept of the mutual influence of local geometry and conformation previously established for globular and water-soluble proteins, our analysis demonstrates that the interplay of backbone geometrical parameters is an intrinsic and general property of protein/peptide structures that is preserved also in nonglobular contexts. For amyloid-forming peptides significant distortions of the N-C(α)-C bond angle, indicative of sterical hidden strain, may occur in correspondence with side chain interdigitation. The correlation between the dihedral angles Δω/ψ in collagen-like models may have interesting implications for triple helix stability.

  2. Noble gases solubility in water

    International Nuclear Information System (INIS)

    Crovetto, Rosa; Fernandez Prini, Roberto.

    1980-07-01

    The available experimental data of solubility of noble gases in water for temperatures smaller than 330 0 C have been critically surveyed. Due to the unique structure of the solvent, the solubility of noble gases in water decreases with temperature passing through a temperature of minimum solubility which is different for each gas, and then increases at higher temperatures. As aresult of the analysis of the experimental data and of the features of the solute-solvent interaction, a generalized equation is proposed which enables thecalculation of Henry's coefficient at different temperatures for all noble gases. (author) [es

  3. Improved Spectra for MALDI MSI of Peptides Using Ammonium Phosphate Monobasic in MALDI Matrix.

    Science.gov (United States)

    Ucal, Yasemin; Ozpinar, Aysel

    2018-05-10

    MALDI mass spectrometry imaging (MSI) enables analysis of peptides along with histology. However, there are several critical steps in MALDI MSI of peptides, one of which is spectral quality. Suppression of MALDI matrix clusters by the aid of ammonium salts in MALDI experiments is well-known. It is asserted that addition of ammonium salts dissociates potential matrix adducts and thereafter decreases matrix cluster formation. Consequently, MALDI MS sensitivity and mass accuracy increases. Up to our knowledge, a limited number of MALDI MSI studies used ammonium salts as matrix additives to suppress matrix clusters and enhance peptide signals. In this work, we investigated the effect of ammonium phosphate monobasic (AmP) as alpha-cyano-4-hydroxycinnamic acid (α-CHCA) matrix additive in MALDI MSI of peptides. Prior to MALDI MSI, the effect of varying concentrations of AmP in α-CHCA were assessed in bovine serum albumin (BSA) tryptic digests and compared with the control (α-CHCA without AmP). Based on our data, the addition of AmP as matrix additive decreased matrix cluster formation regardless of its concentration and, specifically 8 mM AmP and 10 mM AmP increased BSA peptide signal intensities. In MALDI MSI of peptides, both 8 mM, and 10 mM AmP in α-CHCA improved peptide signals especially in the mass range of m/z 2000 to 3000. In particular, 9 peptide signals were found to have differential intensities within the tissues deposited with AmP in α-CHCA (AUC>0.60). To the best of our knowledge, this is the first MALDI MSI of peptides work investigating different concentrations of AmP as α-CHCA matrix additive in order to enhance peptide signals in formalin fixed paraffin embedded (FFPE) tissues. Further, AmP as part of α-CHCA matrix could enhance protein identifications and support MALDI MSI based proteomic approaches. This article is protected by copyright. All rights reserved.

  4. Peptide π-Electron Conjugates: Organic Electronics for Biology?

    Science.gov (United States)

    Ardoña, Herdeline Ann M; Tovar, John D

    2015-12-16

    Highly ordered arrays of π-conjugated molecules are often viewed as a prerequisite for effective charge-transporting materials. Studies involving these materials have traditionally focused on organic electronic devices, with more recent emphasis on biological systems. In order to facilitate the transition to biological environments, biomolecules that can promote hierarchical ordering and water solubility are often covalently appended to the π-electron unit. This review highlights recent work on π-conjugated systems bound to peptide moieties that exhibit self-assembly and aims to provide an overview on the development and emerging applications of peptide-based supramolecular π-electron systems.

  5. Enhanced solubility and targeted delivery of curcumin by lipopeptide micelles.

    Science.gov (United States)

    Liang, Ju; Wu, Wenlan; Lai, Danyu; Li, Junbo; Fang, Cailin

    2015-01-01

    A lipopeptide (LP)-containing KKGRGDS as the hydrophilic heads and lauric acid (C12) as the hydrophobic tails has been designed and prepared by standard solid-phase peptide synthesis technique. LP can self-assemble into spherical micelles with the size of ~30 nm in PBS (phosphate buffer saline) (pH 7.4). Curcumin-loaded LP micelles were prepared in order to increase the water solubility, sustain the releasing rate, and improve the tumor targeted delivery of curcumin. Water solubility, cytotoxicity, in vitro release behavior, and intracellular uptake of curcumin-loaded LP micelles were investigated. The results showed that LP micelles can increase the water solubility of curcumin 1.1 × 10(3) times and sustain the release of curcumin in a low rate. Curcumin-loaded LP micelles showed much higher cell inhibition than free curcumin on human cervix carcinoma (HeLa) and HepG2 cells. When incubating these curcumin-loaded micelles with HeLa and COS7 cells, due to the over-expression of integrins on cancer cells, the micelles can efficiently use the tumor-targeting function of RGD (functionalized peptide sequences: Arg-Gly-Asp) sequence to deliver the drug into HeLa cells, and better efficiency of the self-assembled LP micelles for curcumin delivery than crude curcumin was also confirmed by LCSM (laser confocal scanning microscope) assays. Combined with the enhanced solubility and higher cell inhibition, LP micelles reported in this study may be promising in clinical application for targeted curcumin delivery.

  6. Increased serum soluble corin in dyslipidemia: A cross-sectional study.

    Science.gov (United States)

    Wang, Xiaolei; Chen, Shi; Zhang, Qiu; Liu, Yan; Liu, Lu; Li, Huiling; Peng, Hao

    2015-10-23

    Natriuretic peptides have been associated with dyslipidemia. As a physiological activator of natriuretic peptides, corin might also be associated with dyslipidemia. However, this association has not yet been studied in Chinese populations. Serum soluble corin and blood lipid profiles were determined for 2496 participants aged above 30y. A logistic regression model was applied to evaluate the association between serum soluble corin and dyslipidemia. Serum soluble corin was significantly increased in participants with dyslipidemia in both men (Pdyslipidemia positively increased with increasing levels of serum soluble corin in men (P for trend=0.011) and women (P for trend=0.043). Participants with a high corin level were more likely to have dyslipidemia than those with a low corin level in men (OR, 95% CI: 1.45, 1.07-1.97) and women (OR, 95% CI: 1.33, 1.04-1.70). Serum soluble corin was significantly and positively associated with dyslipidemia. Our findings suggested that serum soluble corin may be a marker or risk factor for dyslipidemia. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Heat shock protein-peptide complex-96 (Vitespen for the treatment of cancer

    Directory of Open Access Journals (Sweden)

    Robert J. Amato

    2011-12-01

    Full Text Available Heat shock proteins (HSPs are the most abundant and ubiquitous soluble intracellular proteins. Members of the HSP family bind peptides, they include antigenic peptides generated within cells. HSPs also interact with antigen-presenting cells (APCs through CD91 and other receptors, eliciting a cascade of events that includes re-presentation of HSP-chaperoned peptides by major histocompatability complex (MHC, translocation of nuclear factorkappaB (NFkB into the nuclei, and maturation of dendritic cells (DCs. These consequences point to a key role of heat shock proteins in fundamental immunological phenomena such as activation of APCs, indirect presentation (or crosspriming of antigenic peptides, and chaperoning of peptides during antigen presentation. The properties of HSPs also allow them to be used for immunotherapy of cancers and infections in novel ways. This paper reviews the development and clinical trial progress of vitespen, an HSP peptide complex vaccine based on tumor-derived glycoprotein 96.

  8. Detachable strong cation exchange monolith, integrated with capillary zone electrophoresis and coupled with pH gradient elution, produces improved sensitivity and numbers of peptide identifications during bottom-up analysis of complex proteomes.

    Science.gov (United States)

    Zhang, Zhenbin; Yan, Xiaojing; Sun, Liangliang; Zhu, Guijie; Dovichi, Norman J

    2015-04-21

    A detachable sulfonate-silica hybrid strong cation-exchange monolith was synthesized in a fused silica capillary, and used for solid phase extraction with online pH gradient elution during capillary zone electrophoresis-tandem mass spectrometry (CZE-MS/MS) proteomic analysis. Tryptic digests were prepared in 50 mM formic acid and loaded onto the strong cation-exchange monolith. Fractions were eluted using a series of buffers with lower concentration but higher pH values than the 50 mM formic acid background electrolyte. This combination of elution and background electrolytes results in both sample stacking and formation of a dynamic pH junction and allows use of relatively large elution buffer volumes while maintaining reasonable peak efficiency and resolution. A series of five pH bumps were applied to elute E. coli tryptic peptides from the monolith, followed by analysis using CZE coupled to an LTQ-Orbitrap Velos mass spectrometer; 799 protein groups and 3381 peptides were identified from 50 ng of the digest in a 2.5 h analysis, which approaches the identification rate for this organism that was obtained with an Orbitrap Fusion. We attribute the improved numbers of peptide and protein identifications to the efficient fractionation by the online pH gradient elution, which decreased the complexity of the sample in each elution step and improved the signal intensity of low abundance peptides. We also performed a comparative analysis using a nanoACQUITY UltraPerformance LCH system. Similar numbers of protein and peptide identifications were produced by the two methods. Protein identifications showed significant overlap between the two methods, whereas peptide identifications were complementary.

  9. Pure Phase Solubility Limits: LANL

    International Nuclear Information System (INIS)

    C. Stockman

    2001-01-01

    The natural and engineered system at Yucca Mountain (YM) defines the site-specific conditions under which one must determine to what extent the engineered and the natural geochemical barriers will prevent the release of radioactive material from the repository. Most important mechanisms for retention or enhancement of radionuclide transport include precipitation or co-precipitation of radionuclide-bearing solid phases (solubility limits), complexation in solution, sorption onto surfaces, colloid formation, and diffusion. There may be many scenarios that could affect the near-field environment, creating chemical conditions more aggressive than the conditions presented by the unperturbed system (such as pH changes beyond the range of 6 to 9 or significant changes in the ionic strength of infiltrated waters). For an extended period of time, the near-field water composition may be quite different and more extreme in pH, ionic strength, and CO 2 partial pressure (or carbonate concentration) than waters at some distance from the repository. Reducing conditions, high pH (up to 11), and low carbonate concentration may be present in the near-field after reaction of infiltrating groundwater with engineered barrier systems, such as cementitious materials. In the far-field, conditions are controlled by the rock-mass buffer providing a near-neutral, oxidizing, low-ionic-strength environment that controls radionuclide solubility limits and sorption capacities. There is the need for characterization of variable chemical conditions that affect solubility, speciation, and sorption reactions. Modeling of the groundwater chemistry is required and leads to an understanding of solubility and speciation of the important radionuclides. Because experimental studies cannot be performed under the numerous potential chemical conditions, solubility limitations must rely on geochemical modeling of the radionuclide's chemistry. Fundamental thermodynamic properties, such as solubility products

  10. Pure Phase Solubility Limits: LANL

    Energy Technology Data Exchange (ETDEWEB)

    C. Stockman

    2001-01-26

    The natural and engineered system at Yucca Mountain (YM) defines the site-specific conditions under which one must determine to what extent the engineered and the natural geochemical barriers will prevent the release of radioactive material from the repository. Most important mechanisms for retention or enhancement of radionuclide transport include precipitation or co-precipitation of radionuclide-bearing solid phases (solubility limits), complexation in solution, sorption onto surfaces, colloid formation, and diffusion. There may be many scenarios that could affect the near-field environment, creating chemical conditions more aggressive than the conditions presented by the unperturbed system (such as pH changes beyond the range of 6 to 9 or significant changes in the ionic strength of infiltrated waters). For an extended period of time, the near-field water composition may be quite different and more extreme in pH, ionic strength, and CO{sub 2} partial pressure (or carbonate concentration) than waters at some distance from the repository. Reducing conditions, high pH (up to 11), and low carbonate concentration may be present in the near-field after reaction of infiltrating groundwater with engineered barrier systems, such as cementitious materials. In the far-field, conditions are controlled by the rock-mass buffer providing a near-neutral, oxidizing, low-ionic-strength environment that controls radionuclide solubility limits and sorption capacities. There is the need for characterization of variable chemical conditions that affect solubility, speciation, and sorption reactions. Modeling of the groundwater chemistry is required and leads to an understanding of solubility and speciation of the important radionuclides. Because experimental studies cannot be performed under the numerous potential chemical conditions, solubility limitations must rely on geochemical modeling of the radionuclide's chemistry. Fundamental thermodynamic properties, such as solubility

  11. Identification of coeliac disease triggering glutenin peptides in adults.

    Science.gov (United States)

    Donnelly, Suzanne C; Šuligoj, Tanja; Ellis, H Julia; Ciclitira, Paul J

    2016-07-01

    Coeliac disease affects approximately 1% of Northern American and European populations. It is caused by an inappropriate immune response to dietary gluten. Gluten comprises of two major protein fractions: gliadins and glutenins. Glutenins have recently been found to be toxic to coeliac individuals. Proliferation assays suggest in some but not all paediatric coeliac individuals there may be immunological stimulation with high molecular weight (HMW) glutenins. Less evidence pertains to low molecular weight (LMW) glutenins. The aim is to assess adaptive, T-cell driven, and innate immune response in adult coeliac individuals towards HMW glutenin peptide, glut04, and LMW glutenin peptide, glt156. Coeliac patients were recruited attending endoscopy for routine monitoring. Adaptive immune response towards glut04 and glt156 was measured by proliferation assays and measurement of interferon-γ secretion in 28 T-cell lines. The innate immune response was assessed by measurement of enterocyte cell height (ECH) in coeliac small intestinal biopsies following overnight incubation in organ culture chambers in a further nine individuals. There were 3/28 and 2/28 positive proliferation results using gluten-sensitive T-cells with glut04 and glt156, respectively. All coeliac biopsies tested in organ culture chambers demonstrated clear reduction in ECH with peptic-tryptic digest of whole industrial gluten, glut04 and glt156 when compared to negative control ovalbumin (p < 0.005). Three individuals had both T-cell and organ culture study data. Their proliferation assays showed no stimulation of the T-cells. This study demonstrates glutenin epitopes glut04 and glt156, while minor T-cell epitopes, are important in their ability to trigger the innate immune response.

  12. Diversity-oriented peptide stapling

    DEFF Research Database (Denmark)

    Tran, Thu Phuong; Larsen, Christian Ørnbøl; Røndbjerg, Tobias

    2017-01-01

    as a powerful method for peptide stapling. However, to date CuAAC stapling has not provided a simple method for obtaining peptides that are easily diversified further. In the present study, we report a new diversity-oriented peptide stapling (DOPS) methodology based on CuAAC chemistry. Stapling of peptides...

  13. PNA Peptide chimerae

    DEFF Research Database (Denmark)

    Koch, T.; Næsby, M.; Wittung, P.

    1995-01-01

    Radioactive labelling of PNA has been performed try linking a peptide segment to the PNA which is substrate for protein kinase A. The enzymatic phosphorylation proceeds in almost quantitative yields....

  14. Interplay between Peptide Bond Geometrical Parameters in Nonglobular Structural Contexts

    OpenAIRE

    Esposito, Luciana; Balasco, Nicole; De Simone, Alfonso; Berisio, Rita; Vitagliano, Luigi

    2013-01-01

    Several investigations performed in the last two decades have unveiled that geometrical parameters of protein backbone show a remarkable variability. Although these studies have provided interesting insights into one of the basic aspects of protein structure, they have been conducted on globular and water-soluble proteins. We report here a detailed analysis of backbone geometrical parameters in nonglobular proteins/peptides. We considered membrane proteins and two distinct fibrous systems (am...

  15. Tumor penetrating peptides

    Directory of Open Access Journals (Sweden)

    Tambet eTeesalu

    2013-08-01

    Full Text Available Tumor-homing peptides can be used to deliver drugs into tumors. Phage library screening in live mice has recently identified homing peptides that specifically recognize the endothelium of tumor vessels, extravasate, and penetrate deep into the extravascular tumor tissue. The prototypic peptide of this class, iRGD (CRGDKGPDC, contains the integrin-binding RGD motif. RGD mediates tumor homing through binding to αv integrins, which are selectively expressed on various cells in tumors, including tumor endothelial cells. The tumor-penetrating properties of iRGD are mediated by a second sequence motif, R/KXXR/K. This C-end Rule (or CendR motif is active only when the second basic residue is exposed at the C-terminus of the peptide. Proteolytic processing of iRGD in tumors activates the cryptic CendR motif, which then binds to neuropilin-1 activating an endocytic bulk transport pathway through tumor tissue. Phage screening has also yielded tumor-penetrating peptides that function like iRGD in activating the CendR pathway, but bind to a different primary receptor. Moreover, novel tumor-homing peptides can be constructed from tumor-homing motifs, CendR elements and protease cleavage sites. Pathologies other than tumors can be targeted with tissue-penetrating peptides, and the primary receptor can also be a vascular zip code of a normal tissue. The CendR technology provides a solution to a major problem in tumor therapy, poor penetration of drugs into tumors. The tumor-penetrating peptides are capable of taking a payload deep into tumor tissue in mice, and they also penetrate into human tumors ex vivo. Targeting with these peptides specifically increases the accumulation in tumors of a variety of drugs and contrast agents, such as doxorubicin, antibodies and nanoparticle-based compounds. Remarkably the drug to be targeted does not have to be coupled to the peptide; the bulk transport system activated by the peptide sweeps along any compound that is

  16. Fingerprinting Desmosine-Containing Elastin Peptides

    Science.gov (United States)

    Schräder, Christoph U.; Heinz, Andrea; Majovsky, Petra; Schmelzer, Christian E. H.

    2015-05-01

    Elastin is a vital protein of the extracellular matrix of jawed vertebrates and provides elasticity to numerous tissues. It is secreted in the form of its soluble precursor tropoelastin, which is subsequently cross-linked in the course of the elastic fiber assembly. The process involves the formation of the two tetrafunctional amino acids desmosine (DES) and isodesmosine (IDES), which are unique to elastin. The resulting high degree of cross-linking confers remarkable properties, including mechanical integrity, insolubility, and long-term stability to the protein. These characteristics hinder the structural elucidation of mature elastin. However, MS2 data of linear and cross-linked peptides released by proteolysis can provide indirect insights into the structure of elastin. In this study, we performed energy-resolved collision-induced dissociation experiments of DES, IDES, their derivatives, and DES-/IDES-containing peptides to determine characteristic product ions. It was found that all investigated compounds yielded the same product ion clusters at elevated collision energies. Elemental composition determination using the exact masses of these ions revealed molecular formulas of the type CxHyN, suggesting that the pyridinium core of DES/IDES remains intact even at relatively high collision energies. The finding of these specific product ions enabled the development of a similarity-based scoring algorithm that was successfully applied on LC-MS/MS data of bovine elastin digests for the identification of DES-/IDES-cross-linked peptides. This approach facilitates the straightforward investigation of native cross-links in elastin.

  17. Peptide aldehyde inhibitors of bacterial peptide deformylases.

    Science.gov (United States)

    Durand, D J; Gordon Green, B; O'Connell, J F; Grant, S K

    1999-07-15

    Bacterial peptide deformylases (PDF, EC 3.5.1.27) are metalloenzymes that cleave the N-formyl groups from N-blocked methionine polypeptides. Peptide aldehydes containing a methional or norleucinal inhibited recombinant peptide deformylase from gram-negative Escherichia coli and gram-positive Bacillus subtilis. The most potent inhibitor was calpeptin, N-CBZ-Leu-norleucinal, which was a competitive inhibitor of the zinc-containing metalloenzymes, E. coli and B. subtilis PDF with Ki values of 26.0 and 55.6 microM, respectively. Cobalt-substituted E. coli and B. subtilis deformylases were also inhibited by these aldehydes with Ki values for calpeptin of 9.5 and 12.4 microM, respectively. Distinct spectral changes were observed upon binding of calpeptin to the Co(II)-deformylases, consistent with the noncovalent binding of the inhibitor rather than the formation of a covalent complex. In contrast, the chelator 1,10-phenanthroline caused the time-dependent inhibition of B. subtilis Co(II)-PDF activity with the loss of the active site metal. The fact that calpeptin was nearly equipotent against deformylases from both gram-negative and gram-positive bacterial sources lends further support to the idea that a single deformylase inhibitor might have broad-spectrum antibacterial activity. Copyright 1999 Academic Press.

  18. Use of synthetic peptide libraries for the H-2Kd binding motif identification.

    Science.gov (United States)

    Quesnel, A; Casrouge, A; Kourilsky, P; Abastado, J P; Trudelle, Y

    1995-01-01

    To identify Kd-binding peptides, an approach based on small peptide libraries has been developed. These peptide libraries correspond to all possible single-amino acid variants of a particular Kd-binding peptide, SYIPSAEYI, an analog of the Plasmodium berghei 252-260 antigenic peptide SYIPSAEKI. In the parent sequence, each position is replaced by all the genetically encoded amino acids (except cysteine). The multiple analog syntheses are performed either by the Divide Couple and Recombine method or by the Single Resin method and generate mixtures containing 19 peptides. The present report deals with the synthesis, the purification, the chemical characterization by amino acid analysis and electrospray mass spectrometry (ES-MS), and the application of such mixtures in binding tests with a soluble, functionally empty, single-chain H-2Kd molecule denoted SC-Kd. For each mixture, bound peptides were eluted and analyzed by sequencing. Since the binding tests were realized in noncompetitive conditions, our results show that a much broader set of peptides bind to Kd than expected from previous studies. This may be of practical importance when looking for low affinity peptides such as tumor peptides capable of eliciting protective immune response.

  19. Urea-modified metal-organic framework of type MIL-101(Cr) for the preconcentration of phosphorylated peptides

    International Nuclear Information System (INIS)

    Yang, Xiaoqing; Xia, Yan

    2016-01-01

    Mass spectrometry (MS) is the most powerful tool in phosphoproteomics research. However, phosphopeptides usually are present in low concentrations and their preconcentration therefore is highly desired. We describe a two-step method for the synthesis of a metal organic framework of the type MIL-101(Cr) that is modified with urea (then designated as MIL-101(Cr)-UR 2 ). It possesses large surface area, good solvent stability and high affinity for some phosphates. Due to the presence of modified urea functions, this material allows for selective and effective enrichment of phosphorylated peptides. It was successfully applied to the enrichment of phosphopeptides from non-fat-milk. The method was applied to the detection of phosphopeptides in a tryptic digest of β-casein where is showed a detection sensitivity as low as 10 −10 M. (author)

  20. On nitrogen solubility in water

    International Nuclear Information System (INIS)

    Kalajda, Yu.A.; Katkov, Yu.D.; Kuznetsov, V.A.; Lastovtsev, A.Yu.; Lastochkin, A.P.; Susoev, V.S.

    1980-01-01

    Presented are the results of experimental investigations on nitrogen solubility in water under 0-15 MPa pressure, at the temperature of 100-340 deg C and nitrogen concentration of 0-5000 n.ml. N 2 /kg H 2 O. Empiric equations are derived and a diagram of nitrogen solubility in water is developed on the basis of the experimental data, as well as critically evaluated published data. The investigation results can be used in analyzing water-gas regime of a primary heat carrier in stream-generating plants with water-water reactors

  1. Preliminary considerations concerning actinide solubilities

    International Nuclear Information System (INIS)

    Newton, T.W.; Bayhurst, B.P.; Daniels, W.R.; Erdal, B.R.; Ogard, A.E.

    1980-01-01

    Work at the Los Alamos Scientific Laboratory on the fundamental solution chemistry of the actinides has thus far been confined to preliminary considerations of the problems involved in developing an understanding of the precipitation and dissolution behavior of actinide compounds under environmental conditions. Attempts have been made to calculate solubility as a function of Eh and pH using the appropriate thermodynamic data; results have been presented in terms of contour maps showing lines of constant solubility as a function of Eh and pH. Possible methods of control of the redox potential of rock-groundwater systems by the use of Eh buffers (redox couples) is presented

  2. Thorium oxalate solubility and morphology

    International Nuclear Information System (INIS)

    Monson, P.R. Jr.; Hall, R.

    1981-10-01

    Thorium was used as a stand-in for studying the solubility and precipitation of neptunium and plutonium oxalates. Thorium oxalate solubility was determined over a range of 0.001 to 10.0 in the concentration parameter [H 2 C 2 O 4 ]/[HNO 3 ] 2 . Morphology of thorium oxide made from the oxalate precipitates was characterized by scanning electron microscopy. The different morphologies found for oxalate-lean and oxalate-rich precipitations were in agreement with predictions based on precipitation theory

  3. Solubility database for TILA-99

    Energy Technology Data Exchange (ETDEWEB)

    Vuorinen, U.; Carlsson, T. [VTT Chemical Technology, Espoo (Finland); Kulmala, S.; Hakanen, M. [Helsinki Univ. (Finland). Lab. of Radiochemistry; Ahonen, L. [Geological Survey of Finland, Espoo (Finland)

    1998-11-01

    The safety assessment of spent fuel disposal requires solubility values for several elements estimated in Finnish disposal conditions. In Finland four sites (Haestholmen, Kivetty, Olkiluoto and Romuvaara) are investigated for the disposal of spent fuel. Haestholmen and OLkiluoto are onshore sites, while Kivetty and Romuvaara are inland sites. Based on groundwater analysis and classification according to salinity at the planned disposal depth mainly fresh groundwater is encountered at Kivetty and Romuvaara, while brackish and saline water-types are met at Haestholmen and Olkiluoto. Very saline, almost brine-type water ({approx}70 g/l) has been found in the deepest parts of the investigated bedrock at one of the sites (Olkiluoto). The reference waters and conditions were chosen according to the water-types. The considered reference conditions incorporated both the near- and far-field, and both oxidizing and reducing conditions were considered. In the reference conditions, the changes in solubilities were also estimated as caused by possible variations in the pH, carbonate content and redox conditions. Uranium, which is the main component of spent fuel is dealt with in a separate report presenting the solubility of uranium and spent fuel dissolution. In this work the solubilities of all the other elements of concern (Am, Cu, Nb, Np, Pa, Pd, Pu, Ra, Se, Sn, Tc, Zr, Cm, Ni, Sr, Th, C, Cl, Cs, Fe, Ho, I, and Sm) in the safety assessment are considered. Some discussion on the corrosion of the spent fuel canister is also presented. For the estimation of solubilities of the elements in question, literature data was collected that mainly comprised experimentally measured concentrations. The sources used were spent fuel experiments, concentrations measured in solubility measurements, natural concentrations and concentrations from natural analogue sites (especially Palmottu and Hyrkkoelae in Finland) as well as the concentrations measured at the Finnish investigation sites

  4. Solubility database for TILA-99

    International Nuclear Information System (INIS)

    Vuorinen, U.; Carlsson, T.; Kulmala, S.; Hakanen, M.

    1998-11-01

    The safety assessment of spent fuel disposal requires solubility values for several elements estimated in Finnish disposal conditions. In Finland four sites (Haestholmen, Kivetty, Olkiluoto and Romuvaara) are investigated for the disposal of spent fuel. Haestholmen and OLkiluoto are onshore sites, while Kivetty and Romuvaara are inland sites. Based on groundwater analysis and classification according to salinity at the planned disposal depth mainly fresh groundwater is encountered at Kivetty and Romuvaara, while brackish and saline water-types are met at Haestholmen and Olkiluoto. Very saline, almost brine-type water (∼70 g/l) has been found in the deepest parts of the investigated bedrock at one of the sites (Olkiluoto). The reference waters and conditions were chosen according to the water-types. The considered reference conditions incorporated both the near- and far-field, and both oxidizing and reducing conditions were considered. In the reference conditions, the changes in solubilities were also estimated as caused by possible variations in the pH, carbonate content and redox conditions. Uranium, which is the main component of spent fuel is dealt with in a separate report presenting the solubility of uranium and spent fuel dissolution. In this work the solubilities of all the other elements of concern (Am, Cu, Nb, Np, Pa, Pd, Pu, Ra, Se, Sn, Tc, Zr, Cm, Ni, Sr, Th, C, Cl, Cs, Fe, Ho, I, and Sm) in the safety assessment are considered. Some discussion on the corrosion of the spent fuel canister is also presented. For the estimation of solubilities of the elements in question, literature data was collected that mainly comprised experimentally measured concentrations. The sources used were spent fuel experiments, concentrations measured in solubility measurements, natural concentrations and concentrations from natural analogue sites (especially Palmottu and Hyrkkoelae in Finland) as well as the concentrations measured at the Finnish investigation sites. The

  5. LC-QTOF-MS identification of porcine-specific peptide in heat treated pork identifies candidate markers for meat species determination.

    Science.gov (United States)

    Sarah, S A; Faradalila, W N; Salwani, M S; Amin, I; Karsani, S A; Sazili, A Q

    2016-05-15

    The purpose of this study was to identify porcine-specific peptide markers from thermally processed meat that could differentiate pork from beef, chevon and chicken meat. In the initial stage, markers from tryptic digested protein of chilled, boiled and autoclaved pork were identified using LC-QTOF-MS. An MRM method was then established for verification. A thorough investigation of LC-QTOF-MS data showed that only seven porcine-specific peptides were consistently detected. Among these peptides, two were derived from lactate dehydrogenase, one from creatine kinase, and four from serum albumin protein. However, MRM could only detect four peptides (EVTEFAK, LVVITAGAR, FVIER and TVLGNFAAFVQK) that were consistently present in pork samples. In conclusion, meat species determination through a tandem mass spectrometry platform shows high potential in providing scientifically valid and reliable results even at peptide level. Besides, the specificity and selectivity offered by the proteomics approach also provide a robust platform for Halal authentication. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. In silico panning for a non-competitive peptide inhibitor

    Directory of Open Access Journals (Sweden)

    Ikebukuro Kazunori

    2007-01-01

    Full Text Available Abstract Background Peptide ligands have tremendous therapeutic potential as efficacious drugs. Currently, more than 40 peptides are available in the market for a drug. However, since costly and time-consuming synthesis procedures represent a problem for high-throughput screening, novel procedures to reduce the time and labor involved in screening peptide ligands are required. We propose the novel approach of 'in silico panning' which consists of a two-stage screening, involving affinity selection by docking simulation and evolution of the peptide ligand using genetic algorithms (GAs. In silico panning was successfully applied to the selection of peptide inhibitor for water-soluble quinoprotein glucose dehydrogenase (PQQGDH. Results The evolution of peptide ligands for a target enzyme was achieved by combining a docking simulation with evolution of the peptide ligand using genetic algorithms (GAs, which mimic Darwinian evolution. Designation of the target area as next to the substrate-binding site of the enzyme in the docking simulation enabled the selection of a non-competitive inhibitor. In all, four rounds of selection were carried out on the computer; the distribution of the docking energy decreased gradually for each generation and improvements in the docking energy were observed over the four rounds of selection. One of the top three selected peptides with the lowest docking energy, 'SERG' showed an inhibitory effect with Ki value of 20 μM. PQQGDH activity, in terms of the Vmax value, was 3-fold lower than that of the wild-type enzyme in the presence of this peptide. The mechanism of the SERG blockage of the enzyme was identified as non-competitive inhibition. We confirmed the specific binding of the peptide, and its equilibrium dissociation constant (KD value was calculated as 60 μM by surface plasmon resonance (SPR analysis. Conclusion We demonstrate an effective methodology of in silico panning for the selection of a non

  7. Soluble ST2 Testing: A Promising Biomarker in the Management of Heart Failure

    Energy Technology Data Exchange (ETDEWEB)

    Villacorta, Humberto, E-mail: hvillacorta@cardiol.br [Universidade Federal Fluminense - Pós-Graduação em Ciências Cardiovasculares, Niterói, RJ (Brazil); Maisel, Alan S. [University of California - Division of Cardiovascular Medicine, San Diego (United States)

    2016-02-15

    ST2 is a member of the interleukin-1 receptor family biomarker and circulating soluble ST2 concentrations are believed to reflect cardiovascular stress and fibrosis. Recent studies have demonstrated soluble ST2 to be a strong predictor of cardiovascular outcomes in both chronic and acute heart failure. It is a new biomarker that meets all required criteria for a useful biomarker. Of note, it adds information to natriuretic peptides (NPs) and some studies have shown it is even superior in terms of risk stratification. Since the introduction of NPs, this has been the most promising biomarker in the field of heart failure and might be particularly useful as therapy guide.

  8. Soluble ST2 Testing: A Promising Biomarker in the Management of Heart Failure

    International Nuclear Information System (INIS)

    Villacorta, Humberto; Maisel, Alan S.

    2016-01-01

    ST2 is a member of the interleukin-1 receptor family biomarker and circulating soluble ST2 concentrations are believed to reflect cardiovascular stress and fibrosis. Recent studies have demonstrated soluble ST2 to be a strong predictor of cardiovascular outcomes in both chronic and acute heart failure. It is a new biomarker that meets all required criteria for a useful biomarker. Of note, it adds information to natriuretic peptides (NPs) and some studies have shown it is even superior in terms of risk stratification. Since the introduction of NPs, this has been the most promising biomarker in the field of heart failure and might be particularly useful as therapy guide

  9. Peptide Integrated Optics.

    Science.gov (United States)

    Handelman, Amir; Lapshina, Nadezda; Apter, Boris; Rosenman, Gil

    2018-02-01

    Bio-nanophotonics is a wide field in which advanced optical materials, biomedicine, fundamental optics, and nanotechnology are combined and result in the development of biomedical optical chips. Silk fibers or synthetic bioabsorbable polymers are the main light-guiding components. In this work, an advanced concept of integrated bio-optics is proposed, which is based on bioinspired peptide optical materials exhibiting wide optical transparency, nonlinear and electrooptical properties, and effective passive and active waveguiding. Developed new technology combining bottom-up controlled deposition of peptide planar wafers of a large area and top-down focus ion beam lithography provides direct fabrication of peptide optical integrated circuits. Finding a deep modification of peptide optical properties by reconformation of biological secondary structure from native phase to β-sheet architecture is followed by the appearance of visible fluorescence and unexpected transition from a native passive optical waveguiding to an active one. Original biocompatibility, switchable regimes of waveguiding, and multifunctional nonlinear optical properties make these new peptide planar optical materials attractive for application in emerging technology of lab-on-biochips, combining biomedical photonic and electronic circuits toward medical diagnosis, light-activated therapy, and health monitoring. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Antimicrobial Peptides from Plants

    Directory of Open Access Journals (Sweden)

    James P. Tam

    2015-11-01

    Full Text Available Plant antimicrobial peptides (AMPs have evolved differently from AMPs from other life forms. They are generally rich in cysteine residues which form multiple disulfides. In turn, the disulfides cross-braced plant AMPs as cystine-rich peptides to confer them with extraordinary high chemical, thermal and proteolytic stability. The cystine-rich or commonly known as cysteine-rich peptides (CRPs of plant AMPs are classified into families based on their sequence similarity, cysteine motifs that determine their distinctive disulfide bond patterns and tertiary structure fold. Cystine-rich plant AMP families include thionins, defensins, hevein-like peptides, knottin-type peptides (linear and cyclic, lipid transfer proteins, α-hairpinin and snakins family. In addition, there are AMPs which are rich in other amino acids. The ability of plant AMPs to organize into specific families with conserved structural folds that enable sequence variation of non-Cys residues encased in the same scaffold within a particular family to play multiple functions. Furthermore, the ability of plant AMPs to tolerate hypervariable sequences using a conserved scaffold provides diversity to recognize different targets by varying the sequence of the non-cysteine residues. These properties bode well for developing plant AMPs as potential therapeutics and for protection of crops through transgenic methods. This review provides an overview of the major families of plant AMPs, including their structures, functions, and putative mechanisms.

  11. Solubility limits on radionuclide dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Kerrisk, J.F.

    1984-12-31

    This paper examines the effects of solubility in limiting dissolution rates of a number of important radionuclides from spent fuel and high-level waste. Two simple dissolution models were used for calculations that would be characteristics of a Yucca Mountain repository. A saturation-limited dissolution model, in which the water flowing through the repository is assumed to be saturated with each waste element, is very conservative in that it overestimates dissolution rates. A diffusion-limited dissolution model, in which element-dissolution rates are limited by diffusion of waste elements into water flowing past the waste, is more realistic, but it is subject to some uncertainty at this time. Dissolution rates of some elements (Pu, Am, Sn, Th, Zr, Sm) are always limited by solubility. Dissolution rates of other elements (Cs, Tc, Np, Sr, C, I) are never solubility limited; their release would be limited by dissolution of the bulk waste form. Still other elements (U, Cm, Ni, Ra) show solubility-limited dissolution under some conditions. 9 references, 3 tables.

  12. Solubility of Nd in brine

    International Nuclear Information System (INIS)

    Khalili, F.I.; Symeopoulos, V.; Chen, J.F.; Choppin, G.R.

    1994-01-01

    The solubility of Nd(III) has been measured at 23±3 C in a synthetic brine at pcH 6.4, 8.4, 10.4 and 12.4. The brine consisted predominantly of (Na+K)Cl and MgCl 2 with an ionic strength of 7.8 M (9.4 m) a solid compound of Nd(III) at each pcH was assigned from X-ray diffraction patterns. The log values of the experimental solubilities decrease fomr -3 at pcH 6.4 to -5.8 at pcH 8.4; at pcH 10.4 and 12.4 the solubility was below the detection limit of -7.5. The experimental solubility does not follow closely the variation with pcH estimated from modeling of the species in solution in equilibrium with the Nd solid using S.I.T. (orig.)

  13. The order of expression is a key factor in the production of active transglutaminase in Escherichia coli by co-expression with its pro-peptide

    Directory of Open Access Journals (Sweden)

    Liu Song

    2011-12-01

    Full Text Available Abstract Background Streptomyces transglutaminase (TGase is naturally synthesized as zymogen (pro-TGase, which is then processed to produce active enzyme by the removal of its N-terminal pro-peptide. This pro-peptide is found to be essential for overexpression of soluble TGase in E. coli. However, expression of pro-TGase by E. coli requires protease-mediated activation in vitro. In this study, we developed a novel co- expression method for the direct production of active TGase in E. coli. Results A TGase from S. hygroscopicus was expressed in E. coli only after fusing with the pelB signal peptide, but fusion with the signal peptide induced insoluble enzyme. Therefore, alternative protocol was designed by co-expressing the TGase and its pro-peptide as independent polypeptides under a single T7 promoter using vector pET-22b(+. Although the pro-peptide was co-expressed, the TGase fused without the signal peptide was undetectable in both soluble and insoluble fractions of the recombinant cells. Similarly, when both genes were expressed in the order of the TGase and the pro-peptide, the solubility of TGase fused with the signal peptide was not improved by the co-expression with its pro-peptide. Interestingly, active TGase was only produced by the cells in which the pro-peptide and the TGase were fused with the signal peptide and sequentially expressed. The purified recombinant and native TGase shared the similar catalytic properties. Conclusions Our results indicated that the pro-peptide can assist correct folding of the TGase inter-molecularly in E. coli, and expression of pro-peptide prior to that of TGase was essential for the production of active TGase. The co-expression strategy based on optimizing the order of gene expression could be useful for the expression of other functional proteins that are synthesized as a precursor.

  14. Acylation of Therapeutic Peptides

    DEFF Research Database (Denmark)

    Trier, Sofie; Henriksen, Jonas Rosager; Jensen, Simon Bjerregaard

    ) , which promotes intestinal growth and is used to treat bowel disorders such as inflammatory bowel diseases and short bowel syndrome, and the 32 amino acid salmon calcitonin (sCT), which lowers blood calcium and is employed in the treatment of post-menopausal osteoporosis and hypercalcemia. The two...... peptides are similar in size and structure, but oppositely charged at physiological pH. Both peptides were acylated with linear acyl chains of systematically increasing length, where sCT was furthermore acylated at two different positions on the peptide backbone. For GLP-2, we found that increasing acyl...... remained optimal overall. The results indicate that rational acylation of GLP-2 can increase its in vitro intestinal absorption, alone or in combination with permeation enhancers, and are consistent with the initial project hypothesis. For sCT, an unpredicted effect of acylation largely superseded...

  15. Small lytic peptides escape the inhibitory effect of heparan sulfate on the surface of cancer cells

    Science.gov (United States)

    2011-01-01

    Background Several naturally occurring cationic antimicrobial peptides (CAPs), including bovine lactoferricin (LfcinB), display promising anticancer activities. These peptides are unaffected by multidrug resistance mechanisms and have been shown to induce a protective immune response against solid tumors, thus making them interesting candidates for developing novel lead structures for anticancer treatment. Recently, we showed that the anticancer activity by LfcinB was inhibited by the presence of heparan sulfate (HS) on the surface of tumor cells. Based on extensive structure-activity relationship studies performed on LfcinB, shorter and more potent peptides have been constructed. In the present study, we have investigated the anticancer activity of three chemically modified 9-mer peptides and the influence of HS and chondroitin sulfate (CS) on their cytotoxic activity. Methods Various cell lines and red blood cells were used to investigate the anticancer activity and selectivity of the peptides. The cytotoxic effect of the peptides against the different cell lines was measured by use of a colorimetric MTT viability assay. The influence of HS and CS on their cytotoxic activity was evaluated by using HS/CS expressing and HS/CS deficient cell lines. The ability of soluble HS and CS to inhibit the cytotoxic activity of the peptides and the peptides' affinity for HS and CS were also investigated. Results The 9-mer peptides displayed selective anticancer activity. Cells expressing HS/CS were equally or more susceptible to the peptides than cells not expressing HS/CS. The peptides displayed a higher affinity for HS compared to CS, and exogenously added HS inhibited the cytotoxic effect of the peptides. Conclusions In contrast to the previously reported inhibitory effect of HS on LfcinB, the present study shows that the cytotoxic activity of small lytic peptides was increased or not affected by cell surface HS. PMID:21453492

  16. Small lytic peptides escape the inhibitory effect of heparan sulfate on the surface of cancer cells

    Directory of Open Access Journals (Sweden)

    Lindin Inger

    2011-03-01

    Full Text Available Abstract Background Several naturally occurring cationic antimicrobial peptides (CAPs, including bovine lactoferricin (LfcinB, display promising anticancer activities. These peptides are unaffected by multidrug resistance mechanisms and have been shown to induce a protective immune response against solid tumors, thus making them interesting candidates for developing novel lead structures for anticancer treatment. Recently, we showed that the anticancer activity by LfcinB was inhibited by the presence of heparan sulfate (HS on the surface of tumor cells. Based on extensive structure-activity relationship studies performed on LfcinB, shorter and more potent peptides have been constructed. In the present study, we have investigated the anticancer activity of three chemically modified 9-mer peptides and the influence of HS and chondroitin sulfate (CS on their cytotoxic activity. Methods Various cell lines and red blood cells were used to investigate the anticancer activity and selectivity of the peptides. The cytotoxic effect of the peptides against the different cell lines was measured by use of a colorimetric MTT viability assay. The influence of HS and CS on their cytotoxic activity was evaluated by using HS/CS expressing and HS/CS deficient cell lines. The ability of soluble HS and CS to inhibit the cytotoxic activity of the peptides and the peptides' affinity for HS and CS were also investigated. Results The 9-mer peptides displayed selective anticancer activity. Cells expressing HS/CS were equally or more susceptible to the peptides than cells not expressing HS/CS. The peptides displayed a higher affinity for HS compared to CS, and exogenously added HS inhibited the cytotoxic effect of the peptides. Conclusions In contrast to the previously reported inhibitory effect of HS on LfcinB, the present study shows that the cytotoxic activity of small lytic peptides was increased or not affected by cell surface HS.

  17. Gas-phase structure and fragmentation pathways of singly protonated peptides with N-terminal arginine.

    Science.gov (United States)

    Bythell, Benjamin J; Csonka, István P; Suhai, Sándor; Barofsky, Douglas F; Paizs, Béla

    2010-11-25

    The gas-phase structures and fragmentation pathways of the singly protonated peptide arginylglycylaspartic acid (RGD) are investigated by means of collision-induced-dissociation (CID) and detailed molecular mechanics and density functional theory (DFT) calculations. It is demonstrated that despite the ionizing proton being strongly sequestered at the guanidine group, protonated RGD can easily be fragmented on charge directed fragmentation pathways. This is due to facile mobilization of the C-terminal or aspartic acid COOH protons thereby generating salt-bridge (SB) stabilized structures. These SB intermediates can directly fragment to generate b(2) ions or facilely rearrange to form anhydrides from which both b(2) and b(2)+H(2)O fragments can be formed. The salt-bridge stabilized and anhydride transition structures (TSs) necessary to form b(2) and b(2)+H(2)O are much lower in energy than their traditional charge solvated counterparts. These mechanisms provide compelling evidence of the role of SB and anhydride structures in protonated peptide fragmentation which complements and supports our recent findings for tryptic systems (Bythell, B. J.; Suhai, S.; Somogyi, A.; Paizs, B. J. Am. Chem. Soc. 2009, 131, 14057-14065.). In addition to these findings we also report on the mechanisms for the formation of the b(1) ion, neutral loss (H(2)O, NH(3), guanidine) fragment ions, and the d(3) ion.

  18. Therapeutic HIV Peptide Vaccine

    DEFF Research Database (Denmark)

    Fomsgaard, Anders

    2015-01-01

    Therapeutic vaccines aim to control chronic HIV infection and eliminate the need for lifelong antiretroviral therapy (ART). Therapeutic HIV vaccine is being pursued as part of a functional cure for HIV/AIDS. We have outlined a basic protocol for inducing new T cell immunity during chronic HIV-1...... infection directed to subdominant conserved HIV-1 epitopes restricted to frequent HLA supertypes. The rationale for selecting HIV peptides and adjuvants are provided. Peptide subunit vaccines are regarded as safe due to the simplicity, quality, purity, and low toxicity. The caveat is reduced immunogenicity...

  19. Descriptors for antimicrobial peptides

    DEFF Research Database (Denmark)

    Jenssen, Håvard

    2011-01-01

    of these are currently being used in quantitative structure--activity relationship (QSAR) studies for AMP optimization. Additionally, some key commercial computational tools are discussed, and both successful and less successful studies are referenced, illustrating some of the challenges facing AMP scientists. Through...... examples of different peptide QSAR studies, this review highlights some of the missing links and illuminates some of the questions that would be interesting to challenge in a more systematic fashion. Expert opinion: Computer-aided peptide QSAR using molecular descriptors may provide the necessary edge...

  20. Solubility of sparingly soluble drug derivatives of anthranilic acid.

    Science.gov (United States)

    Domańska, Urszula; Pobudkowska, Aneta; Pelczarska, Aleksandra

    2011-03-24

    This work is a continuation of our systematic study of the solubility of pharmaceuticals (Pharms). All substances here are derivatives of anthranilic acid, and have an anti-inflammatory direction of action (niflumic acid, flufenamic acid, and diclofenac sodium). The basic thermal properties of pure Pharms, i.e., melting and glass-transition temperatures as well as the enthalpy of melting, have been measured with the differential scanning microcalorimetry technique (DSC). Molar volumes have been calculated with the Barton group contribution method. The equilibrium mole fraction solubilities of three pharmaceuticals were measured in a range of temperatures from 285 to 355 K in three important solvents for Pharm investigations: water, ethanol, and 1-octanol using a dynamic method and spectroscopic UV-vis method. The experimental solubility data have been correlated by means of the commonly known G(E) equation: the NRTL, with the assumption that the systems studied here have revealed simple eutectic mixtures. pK(a) precise measurement values have been investigated with the Bates-Schwarzenbach spectrophotometric method. © 2011 American Chemical Society

  1. δ-Peptides from RuAAC-Derived 1,5-Disubstituted Triazole Units

    KAUST Repository

    Johansson, Johan R.

    2014-02-14

    Non-natural peptides with structures and functions similar to natural peptides have emerged lately in biomedical as well as nanotechnological contexts. They are interesting for pharmaceutical applications since they can adopt structures with new targeting potentials and because they are generally not prone to degradation by proteases. We report here a new set of peptidomimetics derived from δ-peptides, consisting of n units of a 1,5-disubstituted 1,2,3-triazole amino acid (5Tzl). The monomer was prepared using ruthenium-catalyzed azide-alkyne cycloaddition (RuAAC) chemistry using [RuCl2Cp]x as the catalyst, allowing for simpler purification and resulting in excellent yields. This achiral monomer was used to prepare peptide oligomers that are water soluble independent of peptide chain length. Conformational analysis and structural investigations of the oligomers were performed by 2D NOESY NMR experiments, and by quantum chemical calculations using the ωB97X-D functional. These data indicate that several conformations may co-exist with slight energetic differences. Together with their increased hydrophilicity, this feature of homo-5Tzl may prove essential for mimicking natural peptides composed of α-amino acids, where the various secondary structures are achieved by side chain effects and not by the rigidity of the peptide backbone. The improved synthetic method allows for facile variation of the 5Tzl amino acid side chains, further increasing the versatility of these compounds. A new set of non-natural peptides composed of 1,5-disubstituted 1,2,3-triazole amino acids is presented. These peptides benefit from: a) modular synthesis of the monomers, allowing variation of the side chains; b) increased solubility of the oligomers in water, irrespective of peptide length; c) flexibility of the backbone allowing these foldamers to adopt several conformations. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Fine-tuning the physicochemical properties of peptide-based blood-brain barrier shuttles.

    Science.gov (United States)

    Ghasemy, Somaye; García-Pindado, Júlia; Aboutalebi, Fatemeh; Dormiani, Kianoush; Teixidó, Meritxell; Malakoutikhah, Morteza

    2018-05-01

    N-methylation is a powerful method to modify the physicochemical properties of peptides. We previously found that a fully N-methylated tetrapeptide, Ac-(N-MePhe) 4 -CONH 2 , was more lipophilic than its non-methylated analog Ac-(Phe) 4 -CONH 2 . In addition, the former crossed artificial and cell membranes while the latter did not. Here we sought to optimize the physicochemical properties of peptides and address how the number and position of N-methylated amino acids affect these properties. To this end, 15 analogs of Ac-(Phe) 4 -CONH 2 were designed and synthesized in solid-phase. The solubility of the peptides in water and their lipophilicity, as measured by ultra performance liquid chromatography (UPLC) retention times, were determined. To study the permeability of the peptides, the Parallel Artificial Membrane Permeability Assay (PAMPA) was used as an in vitro model of the blood-brain barrier (BBB). Contrary to the parent peptide, the 15 analogs crossed the artificial membrane, thereby showing that N-methylation improved permeability. We also found that N-methylation enhanced lipophilicity but decreased the water solubility of peptides. Our results showed that both the number and position of N-methylated residues are important factors governing the physicochemical properties of peptides. There was no correlation between the number of N-methylated amide bonds and any of the properties measured. However, for the peptides consecutively N-methylated from the N-terminus to the C-terminus (p1, p5, p11, p12 and p16), lipophilicity correlated well with the number of N-methylated amide bonds and the permeability of the peptides. Moreover, the peptides were non-toxic to HEK293T cells, as determined by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Identification of protein binders in works of art by high-performance liquid chromatography-diode array detector analysis of their tryptic digests.

    Science.gov (United States)

    Fremout, Wim; Sanyova, Jana; Saverwyns, Steven; Vandenabeele, Peter; Moens, Luc

    2009-04-01

    Proteins in works of art are generally determined by the relative amounts of amino acids. This method, however, implies a loss of information on the protein structure and its modifications. Consequently, we propose a method based on the analysis of trypsin digests using high-performance liquid chromatography (HPLC) UV diode array detection (DAD) for painting binder studies. All reaction steps are done in the same vial; no extraction methods or sample transfer is needed, reducing the risk of sample losses. A collection of pure binders (collagen, ovalbumin, yolk and casein) as well as homemade and historical paint samples have been investigated with this method. Chromatograms of unknowns at 214 nm and 280 nm are compared with those of the reference samples as a fingerprint. There is a good agreement between many peptides, but others seem to have been lost or their retention time shifted due to small compositional changes because of ageing and degradation of the paint. The results are comparable with the results of other techniques used for binder identification on the same samples, with the additional advantage of differentiation between egg yolk and glair.

  4. Near-field solubility studies

    International Nuclear Information System (INIS)

    Thomason, H.P.; Williams, S.J.

    1992-02-01

    Experimental determinations of the solubilities of americium, plutonium, neptunium, protactinium, thorium, radium, lead, tin, palladium and zirconium are reported. These elements have radioactive isotopes of concern in assessments of radioactive waste disposal. All measurements were made under the highly alkaline conditions typical of the near field of a radioactive waste repository which uses cementitious materials for many of the immobilisation matrices, the backfill and the engineered structures. Low redox potentials, typical of those resulting from the corrosion of iron and steel, were simulated for those elements having more than one accessible oxidation state. The dissolved concentrations of the elements were defined using ultrafiltration. In addition, the corrosion of iron and stainless steel was shown to generate low redox potentials in solution and the solubility of iron(II) at high pH was measured and found to be sufficient for it to act as a redox buffer with respect to neptunium and plutonium. (author)

  5. Antimicrobial Peptides: An Introduction.

    Science.gov (United States)

    Haney, Evan F; Mansour, Sarah C; Hancock, Robert E W

    2017-01-01

    The "golden era" of antibiotic discovery has long passed, but the need for new antibiotics has never been greater due to the emerging threat of antibiotic resistance. This urgency to develop new antibiotics has motivated researchers to find new methods to combat pathogenic microorganisms resulting in a surge of research focused around antimicrobial peptides (AMPs; also termed host defense peptides) and their potential as therapeutics. During the past few decades, more than 2000 AMPs have been identified from a diverse range of organisms (animals, fungi, plants, and bacteria). While these AMPs share a number of common features and a limited number of structural motifs; their sequences, activities, and targets differ considerably. In addition to their antimicrobial effects, AMPs can also exhibit immunomodulatory, anti-biofilm, and anticancer activities. These diverse functions have spurred tremendous interest in research aimed at understanding the activity of AMPs, and various protocols have been described to assess different aspects of AMP function including screening and evaluating the activities of natural and synthetic AMPs, measuring interactions with membranes, optimizing peptide function, and scaling up peptide production. Here, we provide a general overview of AMPs and introduce some of the methodologies that have been used to advance AMP research.

  6. The Solubility Parameters of Ionic Liquids

    Science.gov (United States)

    Marciniak, Andrzej

    2010-01-01

    The Hildebrand’s solubility parameters have been calculated for 18 ionic liquids from the inverse gas chromatography measurements of the activity coefficients at infinite dilution. Retention data were used for the calculation. The solubility parameters are helpful for the prediction of the solubility in the binary solvent mixtures. From the solubility parameters, the standard enthalpies of vaporization of ionic liquids were estimated. PMID:20559495

  7. The Solubility Parameters of Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Andrzej Marciniak

    2010-04-01

    Full Text Available The Hildebrand’s solubility parameters have been calculated for 18 ionic liquids from the inverse gas chromatography measurements of the activity coefficients at infinite dilution. Retention data were used for the calculation. The solubility parameters are helpful for the prediction of the solubility in the binary solvent mixtures. From the solubility parameters, the standard enthalpies of vaporization of ionic liquids were estimated.

  8. Solubility of Carbon in Nanocrystalline -Iron

    OpenAIRE

    Alexander Kirchner; Bernd Kieback

    2012-01-01

    A thermodynamic model for nanocrystalline interstitial alloys is presented. The equilibrium solid solubility of carbon in -iron is calculated for given grain size. Inside the strained nanograins local variation of the carbon content is predicted. Due to the nonlinear relation between strain and solubility, the averaged solubility in the grain interior increases with decreasing grain size. The majority of the global solubility enhancement is due to grain boundary enrichment however. Therefor...

  9. Mimicking protein-protein interactions through peptide-peptide interactions: HIV-1 gp120 and CXCR4

    Directory of Open Access Journals (Sweden)

    Andrea eGross

    2013-09-01

    Full Text Available We have recently designed a soluble synthetic peptide that functionally mimics the HIV-1 coreceptor CXCR4, which is a chemokine receptor that belongs to the family of seven-transmembrane GPCRs. This CXCR4 mimetic peptide, termed CX4-M1, presents the three extracellular loops (ECLs of the receptor. In binding assays involving recombinant proteins, as well as in cellular infection assays, CX4-M1 was found to selectively recognize gp120 from HIV-1 strains that use CXCR4 for cell entry (X4 tropic HIV-1. Furthermore, anti-HIV-1 antibodies modulate this interaction in a molecular mechanism related to that of their impact on the gp120-CXCR4 interaction. We could now show that the selectivity of CX4-M1 pertains not only to gp120 from X4 tropic HIV-1, but also to synthetic peptides presenting the V3 loops of these gp120 proteins. The V3 loop is thought to be an essential part of the coreceptor binding site of gp120 that contacts the second ECL of the coreceptor. We were able to experimentally confirm this notion in binding assays using substitution analogs of CX4-M1 and the V3 loop peptides, respectively, as well as in cellular infection assays. These results indicate that interactions of the HIV-1 Env with coreceptors can be mimicked by synthetic peptides, which may be useful to explore these interactions at the molecular level in more detail.

  10. [Distiller Yeasts Producing Antibacterial Peptides].

    Science.gov (United States)

    Klyachko, E V; Morozkina, E V; Zaitchik, B Ts; Benevolensky, S V

    2015-01-01

    A new method of controlling lactic acid bacteria contamination was developed with the use of recombinant Saccharomyces cerevisiae strains producing antibacterial peptides. Genes encoding the antibacterial peptides pediocin and plantaricin with codons preferable for S. cerevisiae were synthesized, and a system was constructed for their secretory expression. Recombinant S. cerevisiae strains producing antibacterial peptides effectively inhibit the growth of Lactobacillus sakei, Pediacoccus pentasaceus, Pediacoccus acidilactici, etc. The application of distiller yeasts producing antibacterial peptides enhances the ethanol yield in cases of bacterial contamination. Recombinant yeasts producing the antibacterial peptides pediocin and plantaricin can successfully substitute the available industrial yeast strains upon ethanol production.

  11. A qualitative and quantitative evaluation of the peptide characteristics of microwave- and ultrasound-assisted digestion in discovery and targeted proteomic analyses.

    Science.gov (United States)

    Guo, Zhengguang; Cheng, Jie; Sun, Haidan; Sun, Wei

    2017-08-30

    Fast digestion methods can dramatically accelerate enzyme digestion and increase the throughput of proteomic analysis. However, the peptide characteristics of fast digestion methods and their performance in discovery and targeted proteomic analysis must be systematically evaluated. Three digestion methods, including overnight digestion, microwave-assisted protein enzymatic digestion (MAPED), and high-intensity focused ultrasonic-assisted enzymatic digestion (HIFUSAED), in trypsin or in trypsin/Lys-C were comprehensively compared in both discovery and targeted proteomics analysis using the HeLa cell proteome. In discovery proteomic analysis, the highest numbers of peptides and proteins were identified when the sample was digested via the MAPED method with trypsin/Lys-C. The fast digestion methods showed a higher mis-cleavage rate and a lower semi-tryptic rate than the overnight digestion method. In both label-free quantitative analysis and targeted proteomic analysis, both fully cleaved peptides (FCPs) and mis-cleaved peptides (MCPs) from the fast digestion methods and the overnight digestion method showed good reproducibility if they showed good abundance. When both the FCPs and MCPs were included in the analysis, the MAPED with trypsin/Lys-C method showed the best results for both discovery proteomic analysis and relative quantitative targeted proteomic analysis. These results will be beneficial for the application of fast digestion methods to proteomics. Copyright © 2017 John Wiley & Sons, Ltd.

  12. Ligand-regulated peptide aptamers.

    Science.gov (United States)

    Miller, Russell A

    2009-01-01

    The peptide aptamer approach employs high-throughput selection to identify members of a randomized peptide library displayed from a scaffold protein by virtue of their interaction with a target molecule. Extending this approach, we have developed a peptide aptamer scaffold protein that can impart small-molecule control over the aptamer-target interaction. This ligand-regulated peptide (LiRP) scaffold, consisting of the protein domains FKBP12, FRB, and GST, binds to the cell-permeable small-molecule rapamycin and the binding of this molecule can prevent the interaction of the randomizable linker region connecting FKBP12 with FRB. Here we present a detailed protocol for the creation of a peptide aptamer plasmid library, selection of peptide aptamers using the LiRP scaffold in a yeast two-hybrid system, and the screening of those peptide aptamers for a ligand-regulated interaction.

  13. Biosynthesis of cardiac natriuretic peptides

    DEFF Research Database (Denmark)

    Goetze, Jens Peter

    2010-01-01

    Cardiac-derived peptide hormones were identified more than 25 years ago. An astonishing amount of clinical studies have established cardiac natriuretic peptides and their molecular precursors as useful markers of heart disease. In contrast to the clinical applications, the biogenesis of cardiac...... peptides has only been elucidated during the last decade. The cellular synthesis including amino acid modifications and proteolytic cleavages has proven considerably more complex than initially perceived. Consequently, the elimination phase of the peptide products in circulation is not yet well....... An inefficient post-translational prohormone maturation will also affect the biology of the cardiac natriuretic peptide system. This review aims at summarizing the myocardial synthesis of natriuretic peptides focusing on B-type natriuretic peptide, where new data has disclosed cardiac myocytes as highly...

  14. Radiolabelled peptides for oncological diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Laverman, Peter; Boerman, Otto C.; Oyen, Wim J.G. [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine, Nijmegen (Netherlands); Sosabowski, Jane K. [Queen Mary University of London, Centre for Molecular Oncology, Barts Cancer Institute, London (United Kingdom)

    2012-02-15

    Radiolabelled receptor-binding peptides targeting receptors (over)expressed on tumour cells are widely under investigation for tumour diagnosis and therapy. The concept of using radiolabelled receptor-binding peptides to target receptor-expressing tissues in vivo has stimulated a large body of research in nuclear medicine. The {sup 111}In-labelled somatostatin analogue octreotide (OctreoScan trademark) is the most successful radiopeptide for tumour imaging, and was the first to be approved for diagnostic use. Based on the success of these studies, other receptor-targeting peptides such as cholecystokinin/gastrin analogues, glucagon-like peptide-1, bombesin (BN), chemokine receptor CXCR4 targeting peptides, and RGD peptides are currently under development or undergoing clinical trials. In this review, we discuss some of these peptides and their analogues, with regard to their potential for radionuclide imaging of tumours. (orig.)

  15. Dimeric MHC-peptides inserted into an immunoglobulin scaffold as new immunotherapeutic agents

    Science.gov (United States)

    Goldberg, Burt; Bona, Constantin

    2011-01-01

    Abstract The interactions of the T cell receptor (TCR) with cognate MHC-peptide and co-stimulatory molecules expressed at surface of antigen presenting cells (APC) leads to activation or tolerance of T cells. The development of molecular biological tools allowed for the preparation of soluble MHC-peptide molecules as surrogate for the APC. A decade ago a monomeric class II MHC molecule in which the peptide was covalently linked to β-chain of class II molecule was generated. This type of molecule had a low-binding affinity and did not cause the multimerization of TCR. The requirement of multimerization of TCR led to development of a new class of reagents, chimeric peptides covalently linked to MHC that was dimerized via Fc fragment of an immunoglobulin and linked to 3′ end of the β-chain of MHC class II molecule. These soluble dimerized MHC-peptide chimeric molecules display high affinity for the TCR and caused multimerization of TCR without processing by an APC. Because dimeric molecules are devoid of co-stimulatory molecules interacting with CD28, a second signal, they induce anergy rather the activation of T cells. In this review, we compare the human and murine dimerized MHC class II-peptides and their effect on CD4+ T cells, particularly the generation of T regulatory cells, which make these chimeric molecules an appealing approach for the treatment of autoimmune diseases. PMID:21435177

  16. Antimicrobial Peptides (AMPs

    Directory of Open Access Journals (Sweden)

    Mehrzad Sadredinamin

    2016-04-01

    Full Text Available Antimicrobial peptides (AMPs are extensive group of molecules that produced by variety tissues of invertebrate, plants, and animal species which play an important role in their immunity response. AMPs have different classifications such as; biosynthetic machines, biological sources, biological functions, molecular properties, covalent bonding patterns, three dimensional structures, and molecular targets.These molecules have multidimensional properties including antimicrobial activity, antiviral activity, antifungal activity, anti-parasite activity, biofilm control, antitumor activity, mitogens activity and linking innate to adaptive immunity that making them promising agents for therapeutic drugs. In spite of this advantage of AMPs, their clinical developments have some limitation for commercial development. But some of AMPs are under clinical trials for the therapeutic purpose such as diabetic foot ulcers, different bacterial infections and tissue damage. In this review, we emphasized on the source, structure, multidimensional properties, limitation and therapeutic applications of various antimicrobial peptides.

  17. Enhanced Intestinal Permeability of Bufalin by a Novel Bufalin-Peptide-Dendrimer Inclusion through Caco-2 Cell Monolayer

    OpenAIRE

    Chi-on Chan; Jing Jing; Wei Xiao; Zhexu Tan; Qiuyue Lv; Jingyu Yang; Sibao Chen

    2017-01-01

    Bufalin (BFL) has excellent physiological activities such as defending tumors, improving cardiac function, and so on. However, due to its poor water-solubility and bioavailability, the clinical application of BFL remains limited. In order to improve bioavailability of BFL, in our previous research, a novel peptide-dendrimer (PD) was synthesized and applied to encapsulate BFL. In the present study, we investigate the absorption property and mechanism of BFL in free form and BFL-peptide-dendrim...

  18. Characterization of reaction conditions providing rapid and specific cysteine alkylation for peptide-based mass spectrometry.

    Science.gov (United States)

    Paulech, Jana; Solis, Nestor; Cordwell, Stuart J

    2013-01-01

    Alkylation converts Cys thiols to thioethers and prevents unwanted side reactions, thus facilitating mass spectrometric identification of Cys-containing peptides. Alkylation occurs preferentially at Cys due to its high nucleophilicity, however reactions at other such sites are possible. N-ethylmaleimide (NEM) shows rapid reaction kinetics with Cys and careful definition of reaction conditions results in little reactivity at other sites. Analysis of a protein standard alkylated under differing reaction conditions (pH, NEM concentrations and reaction times) was performed using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) and selected reaction monitoring (SRM) of NEM-modified and unmodified peptide pairs. Mis-alkylation sites at primary and secondary amines were identified and limited to one equivalent of NEM. No evidence for hydroxyl or thioether alkylation was observed. Improved specificity was achieved by restricting the pH below neutral, NEM concentration below 10mM and/or reaction time to below 5min. Maximal removal of Cys activity was observed in tissue homogenates at 40mM NEM within 1min, dependent upon efficient protein denaturation. SRM assays identified peptide-specific levels of mis-alkylation, indicating that NEM-modified to unmodified ratios did not exceed 10%, with the exception of Cys alkylation that proceeded to 100%, and some Lys residues that resulted in tryptic missed cleavages. High reactivity was observed for His residues considering their relatively low abundance. These data indicate that rapid and specific Cys alkylation is possible with NEM under relatively mild conditions, with more abrasive conditions leading to increased non-specific alkylation without appreciable benefit for MS-based proteomics. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Involvement of the Soluble Urokinase Receptor in Chondrosarcoma Cell Mobilization

    Directory of Open Access Journals (Sweden)

    Katia Bifulco

    2011-01-01

    Full Text Available High levels of urokinase receptor (uPAR in tissue and serum of patients with chondrosarcoma correlate with poor prognosis. First, we analyzed the uPAR levels in tissues and plasma of five patients affected by chondrosarcoma. Interestingly, very high levels of uPAR and its soluble forms (SuPAR were found on tumor cell surfaces and plasma, respectively, of two patients with lung metastases. Therefore, to investigate the role of SuPAR in chondrosaromas, we generated a primary cell culture from a chondrosarcoma tissue overexpressing uPAR on cell surfaces. We found that chondrosarcoma-like primary culture cells release a large amount of SuPAR in the medium. In vitro, SuPAR elicits chondrosarcoma cell migration likely through its uPAR88-92 sequence, since the DII88-183 or DIIDIIR88-284 uPAR domains retain motogen effect whereas DI1-87 or DIII184-284 domains, both lacking the uPAR88-92 sequence, are ineffective. Chondrosarcoma cells cross matrigel in response to SuPAR, and their invasion capability is abrogated by RERF peptide which inhibits uPAR88-92 signalling. These findings assign a role to uPAR in mobilizing chondrosarcoma cells and suggest that RERF peptide may be regarded as a prototype to generate new therapeutics for the chondrosarcoma treatment.

  20. Phenol-Soluble Modulin Toxins of Staphylococcus haemolyticus

    Directory of Open Access Journals (Sweden)

    Fei Da

    2017-05-01

    Full Text Available Coagulase-negative staphylococci (CoNS are important nosocomial pathogens and the leading cause of sepsis. The second most frequently implicated species, after Staphylococcus epidermidis, is Staphylococcus haemolyticus. However, we have a significant lack of knowledge about what causes virulence of S. haemolyticus, as virulence factors of this pathogen have remained virtually unexplored. In contrast to the aggressive pathogen Staphylococcus aureus, toxin production has traditionally not been associated with CoNS. Recent findings have suggested that phenol-soluble modulins (PSMs, amphipathic peptide toxins with broad cytolytic activity, are widespread in staphylococci, but there has been no systematic assessment of PSM production in CoNS other than S. epidermidis. Here, we identified, purified, and characterized PSMs of S. haemolyticus. We found three PSMs of the β-type, which correspond to peptides that before were described to have anti-gonococcal activity. We also detected an α-type PSM that has not previously been described. Furthermore, we confirmed that S. haemolyticus does not produce a δ-toxin, as results from genome sequencing had indicated. All four S. haemolyticus PSMs had strong pro-inflammatory activity, promoting neutrophil chemotaxis. Notably, we identified in particular the novel α-type PSM, S. haemolyticus PSMα, as a potent hemolysin and leukocidin. For the first time, our study describes toxins of this important staphylococcal pathogen with the potential to have a significant impact on virulence during blood infection and sepsis.

  1. Biological properties of water-soluble phosphorhydrazone dendrimers

    Directory of Open Access Journals (Sweden)

    Anne-Marie Caminade

    2013-01-01

    Full Text Available Dendrimers are hyperbranched and perfectly defined macromolecules, constituted of branches emanating from a central core in an iterative fashion. Phosphorhydrazone dendrimers constitute a special family of dendrimers, possessing one phosphorus atom at each branching point. The internal structure of these dendrimers is hydrophobic, but hydrophilic terminal groups can induce the solubility of the whole structure in water. Indeed, the properties of these compounds are mainly driven by the type of terminal groups their bear; this is especially true for the biological properties. For instance, positively charged terminal groups are efficient for transfection experiments, as drug carriers, as anti-prion agents, and as inhibitor of the aggregation of Alzheimer's peptides, whereas negatively charged dendrimers have anti-HIV properties and can influence the human immune system, leading to anti-inflammatory properties usable against rheumatoid arthritis. This review will give the most representative examples of the biological properties of water-soluble phosphorhydrazone dendrimers, organized depending on the type of terminal groups they bear.

  2. Therapeutic peptides for cancer therapy. Part II - cell cycle inhibitory peptides and apoptosis-inducing peptides.

    Science.gov (United States)

    Raucher, Drazen; Moktan, Shama; Massodi, Iqbal; Bidwell, Gene L

    2009-10-01

    Therapeutic peptides have great potential as anticancer agents owing to their ease of rational design and target specificity. However, their utility in vivo is limited by low stability and poor tumor penetration. The authors review the development of peptide inhibitors with potential for cancer therapy. Peptides that arrest the cell cycle by mimicking CDK inhibitors or induce apoptosis directly are discussed. The authors searched Medline for articles concerning the development of therapeutic peptides and their delivery. Inhibition of cancer cell proliferation directly using peptides that arrest the cell cycle or induce apoptosis is a promising strategy. Peptides can be designed that interact very specifically with cyclins and/or cyclin-dependent kinases and with members of apoptotic cascades. Use of these peptides is not limited by their design, as a rational approach to peptide design is much less challenging than the design of small molecule inhibitors of specific protein-protein interactions. However, the limitations of peptide therapy lie in the poor pharmacokinetic properties of these large, often charged molecules. Therefore, overcoming the drug delivery hurdles could open the door for effective peptide therapy, thus making an entirely new class of molecules useful as anticancer drugs.

  3. Simultaneously tracing the geographical origin and presence of bovine milk in Italian water buffalo Mozzarella cheese using MALDI-TOF data of casein signature peptides.

    Science.gov (United States)

    Caira, Simonetta; Pinto, Gabriella; Nicolai, Maria Adalgisa; Chianese, Lina; Addeo, Francesco

    2016-08-01

    Water buffalo (WB) casein (CN) and curd samples from indigenous Italian and international breeds were examined with the objective of identifying signature peptides that could function as an indicator to determine the origin of their milk products. CN in complex mixtures were digested with trypsin, and peptide fragments were subsequently identified by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS). The unique presence of a β-CN A variant and an internally deleted αs1-CN (f35-42) variant in international WB milk samples was ascertained by identifying signature tryptic peptides from either dephosphorylated or native CN. Four signature unphosphorylated peptides derived from β-CN A, i.e. (f49-68) Asn(68) (2223.6 Da), (f1-28) Ser(10) (3169.4 Da), (f1-29) Ser(10) (3297.4 Da) and (f33-48) Thr(41) (1982 Da) and two from αs1-CN (f35-42) deleted fragments, i.e. (f23-34) Met(31) (1415.7 Da) and (f43-58) Val(44) (1752.7 Da), were identified. Two signature casein phosphopeptides (CPPs), i.e. β-CN (f1-28) 4P (3489.1 Da) and β-CN (f33-48) 1P (2062.0 Da), were identified in the tryptic hydrolysate of native casein or curd and cheese samples using in-batch hydroxyapatite (HA) chromatography. All these fragments functioned as analytical surrogates of two αs1- and β-casein variants that specifically occur in the milk of international WB breeds. Furthermore, the bovine peptide β-CN (f1-28) 4P had a distinct and lower molecular mass compared with the WB counterpart and functioned as a species-specific marker for all breeds of WB. Advantages of this analytical approach are that (i) peptides are easier to separate than proteins, (ii) signature peptide probes originating from specific casein variants allow for the targeting of all international WB milk, curd and cheese samples and (iii) bovine and WB casein in mixtures can be simultaneously determined in protected designation of origin (PDO) "Mozzarella di Bufala Campana" cheese

  4. Tetrazine-Containing Amino Acid for Peptide Modification and Live Cell Labeling.

    Directory of Open Access Journals (Sweden)

    Zhongqiu Ni

    Full Text Available A novel amino acid derivative 3-(4-(1, 2, 4, 5-tetrazine-3-yl phenyl-2-aminopropanoic acid was synthesized in this study. The compound possessed better water-solubility and was synthesized more easily compared with the well-known and commercially available 3-(p-benzylamino-1, 2, 4, 5-tetrazine. Tetrazine-containing amino acid showed excellent stability in biological media and might be used for cancer cell labeling. Moreover, the compound remained relatively stable in 50% TFA/DCM with little decomposition after prolonged exposure at room temperature. The compound could be utilized as phenylalanine or tyrosine analogue in peptide modification, and the tetrazine-containing peptide demonstrated more significant biological activity than that of the parent peptide. The combination of tetrazine group and amino acid offered broad development prospects of the bioorthogonal labeling and peptide synthesis.

  5. Absolute Quantitation of Glycoforms of Two Human IgG Subclasses Using Synthetic Fc Peptides and Glycopeptides

    Science.gov (United States)

    Roy, Rini; Ang, Evelyn; Komatsu, Emy; Domalaon, Ronald; Bosseboeuf, Adrien; Harb, Jean; Hermouet, Sylvie; Krokhin, Oleg; Schweizer, Frank; Perreault, Hélène

    2018-05-01

    Immunoglobulins, such as immunoglobulin G (IgG), are of prime importance in the immune system. Polyclonal human IgG comprises four subclasses, of which IgG1 and IgG2 are the most abundant in healthy individuals. In an effort to develop an absolute MALDI-ToF-MS quantitative method for these subclasses and their Fc N-glycoforms, (glyco)peptides were synthesized using a solid-phase approach and used as internal standards. Tryptic digest glycopeptides from monoclonal IgG1 and IgG2 samples were first quantified using EEQYN(GlcNAc)STYR and EEQFN(GlcNAc)STFR standards, respectively. For IgG1, a similar glycopeptide where tyrosine (Y) was isotopically labelled was used to quantify monoclonal IgG1 that had been treated with the enzyme Endo-F2, i.e., yielding tryptic glycopeptide EEQYN(GlcNAc)STYR. The next step was to quantify single subclasses within polyclonal human IgG samples. Although ion abundances in the MALDI spectra often showed higher signals for IgG2 than IgG1, depending on the spotting solvent used, determination of amounts using the newly developed quantitative method allowed to obtain accurate concentrations where IgG1 species were predominant. It was observed that simultaneous analysis of IgG1 and IgG2 yielded non-quantitative results and that more success was obtained when subclasses were quantified one by one. More experiments served to assess the respective extraction and ionization efficiencies of EEQYNSTYR/EEQFNSTFR and EEQYN(GlcNAc)STYR/EEQFN(GlcNAc)STFR mixtures under different solvent and concentration conditions.

  6. Solid-phase peptide synthesis

    DEFF Research Database (Denmark)

    Jensen, Knud Jørgen

    2013-01-01

    This chapter provides an introduction to and overview of peptide chemistry with a focus on solid-phase peptide synthesis. The background, the most common reagents, and some mechanisms are presented. This chapter also points to the different chapters and puts them into perspective.......This chapter provides an introduction to and overview of peptide chemistry with a focus on solid-phase peptide synthesis. The background, the most common reagents, and some mechanisms are presented. This chapter also points to the different chapters and puts them into perspective....

  7. Improving Peptide Applications Using Nanotechnology.

    Science.gov (United States)

    Narayanaswamy, Radhika; Wang, Tao; Torchilin, Vladimir P

    2016-01-01

    Peptides are being successfully used in various fields including therapy and drug delivery. With advancement in nanotechnology and targeted delivery carrier systems, suitable modification of peptides has enabled achievement of many desirable goals over-riding some of the major disadvantages associated with the delivery of peptides in vivo. Conjugation or physical encapsulation of peptides to various nanocarriers, such as liposomes, micelles and solid-lipid nanoparticles, has improved their in vivo performance multi-fold. The amenability of peptides to modification in chemistry and functionalization with suitable nanocarriers are very relevant aspects in their use and have led to the use of 'smart' nanoparticles with suitable linker chemistries that favor peptide targeting or release at the desired sites, minimizing off-target effects. This review focuses on how nanotechnology has been used to improve the number of peptide applications. The paper also focuses on the chemistry behind peptide conjugation to nanocarriers, the commonly employed linker chemistries and the several improvements that have already been achieved in the areas of peptide use with the help of nanotechnology.

  8. Nanosuspension Technology for Solubilizing Poorly Soluble Drugs

    OpenAIRE

    Deoli Mukesh

    2012-01-01

    Poor water solubility for many drugs and drug candidates remains a major obstacle to their development and clinical application. It is estimated that around 40% of drugs in the pipeline cannot be delivered through the preferred route or in some cases, at all owing to poor water solubility. Conventional formulations to improve solubility suffer from low bioavailability and poor pharmacokinetics, with some carriers rendering systemic toxicities (e.g. Cremophor1 EL). To date, nanoscale systems f...

  9. Soluble theory with massive ghosts

    International Nuclear Information System (INIS)

    Pisarski, R.D.

    1983-01-01

    To investigate the unitarity of asymptotically free, higher-derivative theories, like certain models of quantum gravity, I study a prototype in two space-time dimensions. The prototype is a kind of higher-derivative nonlinear sigma model; it is asymptotically free, exhibits dimensional transmutation, and is soluble in a large-N expansion. The S-matrix elements, constructed from the analytic continuation of the Euclidean Green's functions, conserve probability to approx.O(N -1 ), but violate unitarity at approx.O(N -2 ). The model demonstrates that in higher-derivative theories unitarity, or the lack thereof, cannot be decided without explicit control over the infrared limit. Even so, the results suggest that there may exist some (rather special) asymptotically free, higher-derivative theories which are unitary

  10. Anticancer peptides from bacteria

    Directory of Open Access Journals (Sweden)

    Tomasz M. Karpiński

    2013-08-01

    Full Text Available Cancer is a leading cause of death in the world. The rapid development of medicine and pharmacology allows to create new and effective anticancer drugs. Among modern anticancer drugs are bacterial proteins. Until now has been shown anticancer activity among others azurin and exotoxin A from Pseudomonas aeruginosa, Pep27anal2 from Streptococcus pneumoniae, diphtheria toxin from Corynebacterium diphtheriae, and recently discovered Entap from Enterococcus sp. The study presents the current data regarding the properties, action and anticancer activity of listed peptides.

  11. Evaluation of online carbon isotope dilution mass spectrometry for the purity assessment of synthetic peptide standards

    Energy Technology Data Exchange (ETDEWEB)

    Díaz, Sergio Cueto; Ruiz Encinar, Jorge, E-mail: ruizjorge@uniovi.es; García Alonso, J. Ignacio, E-mail: jiga@uniovi.es

    2014-09-24

    Highlights: • Purity assessment of peptide standards applicable to any water soluble peptide. • Online {sup 13}C isotope dilution mass spectrometry. • Mass flow chromatogram from measured 44/45 isotope ratios. • Validation by the analysis of NIST 8327. - Abstract: We present a novel method for the purity assessment of peptide standards which is applicable to any water soluble peptide. The method is based on the online {sup 13}C isotope dilution approach in which the peptide is separated from its related impurities by liquid chromatography (LC) and the eluent is mixed post-column with a continuous flow of {sup 13}C-enriched sodium bicarbonate. An online oxidation step using sodium persulfate in acidic media at 99 °C provides quantitative oxidation to {sup 12}CO{sub 2} and {sup 13}CO{sub 2} respectively which is extracted to a gaseous phase with the help of a gas permeable membrane. The measurement of the isotope ratio 44/45 in the mass spectrometer allows the construction of the mass flow chromatogram. As the only species that is finally measured in the mass spectrometer is CO{sub 2}, the peptide content in the standard can be quantified, on the base of its carbon content, using a generic primary standard such as potassium hydrogen phthalate. The approach was validated by the analysis of a reference material (NIST 8327), and applied to the quantification of two commercial synthetic peptide standards. In that case, the results obtained were compared with those obtained using alternative methods, such as amino acid analysis and ICP-MS. The results obtained proved the value of the method for the fast, accurate and precise mass purity assignment of synthetic peptide standards.

  12. Issues concerning the determination of solubility products of sparingly soluble crystalline solids. Solubility of HfO2(cr)

    International Nuclear Information System (INIS)

    Rai, Dhanpat; Kitamura, Akira; Rosso, Kevin M.; Sasaki, Takayuki; Kobayashi, Taishi

    2016-01-01

    Solubility studies were conducted with HfO 2 (cr) solid as a function HCl and ionic strength ranging from 2.0 to 0.004 mol kg -1 . These studies involved (1) using two different amounts of the solid phase, (2) acid washing the bulk solid phase, (3) preheating the solid phase to 1400 C, and (4) heating amorphous HfO 2 (am) suspensions to 90 C to ascertain whether the HfO 2 (am) converts to HfO 2 (cr) and to determine the solubility from the oversaturation direction. Based on the results of these treatments it is concluded that the HfO 2 (cr) contains a small fraction of less crystalline, but not amorphous, material [HfO 2 (lcr)] and this, rather than the HfO 2 (cr), is the solubility-controlling phase in the range of experimental variables investigated in this study. The solubility data are interpreted using both the Pitzer and SIT models and they provide log 10 K 0 values of -(59.75±0.35) and -(59.48±0.41), respectively, for the solubility product of HfO 2 (lcr)[HfO 2 (lcr) + 2H 2 O ↔ Hf 4+ + 4OH - ]. The log 10 of the solubility product of HfO 2 (cr) is estimated to be < -63. The observation of a small fraction of less crystalline higher solubility material is consistent with the general picture that mineral surfaces are often structurally and/or compositionally imperfect leading to a higher solubility than the bulk crystalline solid. This study stresses the urgent need, during interpretation of solubility data, of taking precautions to make certain that the observed solubility behavior for sparingly-soluble solids is assigned to the proper solid phase.

  13. Issues concerning the determination of solubility products of sparingly soluble crystalline solids. Solubility of HfO{sub 2}(cr)

    Energy Technology Data Exchange (ETDEWEB)

    Rai, Dhanpat [Rai Enviro-Chem, LLC, Yachats, OR (United States); Kitamura, Akira [Japan Atomic Energy Agency, Ibaraki (Japan); Rosso, Kevin M. [Pacific Northwest National Laboratory, Richland, WA (United States); Sasaki, Takayuki; Kobayashi, Taishi [Kyoto Univ. (Japan)

    2016-11-01

    Solubility studies were conducted with HfO{sub 2}(cr) solid as a function HCl and ionic strength ranging from 2.0 to 0.004 mol kg{sup -1}. These studies involved (1) using two different amounts of the solid phase, (2) acid washing the bulk solid phase, (3) preheating the solid phase to 1400 C, and (4) heating amorphous HfO{sub 2}(am) suspensions to 90 C to ascertain whether the HfO{sub 2}(am) converts to HfO{sub 2}(cr) and to determine the solubility from the oversaturation direction. Based on the results of these treatments it is concluded that the HfO{sub 2}(cr) contains a small fraction of less crystalline, but not amorphous, material [HfO{sub 2}(lcr)] and this, rather than the HfO{sub 2}(cr), is the solubility-controlling phase in the range of experimental variables investigated in this study. The solubility data are interpreted using both the Pitzer and SIT models and they provide log{sub 10} K{sup 0} values of -(59.75±0.35) and -(59.48±0.41), respectively, for the solubility product of HfO{sub 2}(lcr)[HfO{sub 2}(lcr) + 2H{sub 2}O ↔ Hf{sup 4+} + 4OH{sup -}]. The log{sub 10} of the solubility product of HfO{sub 2}(cr) is estimated to be < -63. The observation of a small fraction of less crystalline higher solubility material is consistent with the general picture that mineral surfaces are often structurally and/or compositionally imperfect leading to a higher solubility than the bulk crystalline solid. This study stresses the urgent need, during interpretation of solubility data, of taking precautions to make certain that the observed solubility behavior for sparingly-soluble solids is assigned to the proper solid phase.

  14. Retrograde curves of solidus and solubility

    International Nuclear Information System (INIS)

    Vasil'ev, M.V.

    1979-01-01

    The investigation was concerned with the constitutional diagrams of the eutectic type with ''retrograde solidus'' and ''retrograde solubility curve'' which must be considered as diagrams with degenerate monotectic transformation. The solidus and the solubility curves form a retrograde curve with a common retrograde point representing the solubility maximum. The two branches of the Aetrograde curve can be described with the aid of two similar equations. Presented are corresponding equations for the Cd-Zn system and shown is the possibility of predicting the run of the solubility curve

  15. Solubility limits of importance to leaching

    International Nuclear Information System (INIS)

    Ogard, A.; Bentley, G.; Bryant, E.; Duffy, C.; Grisham, J.; Norris, E.; Orth, C.; Thomas, K.

    1981-01-01

    The solubilities of some radionuclides, especially rare earths and actinides, may be an important and controlling factor in leaching of waste forms. These solubilities should be measured accurately as a function of pH and not as a part of a multicomponent system. Individual solubilities should be measured as a function of temperature to determine if a kinetic effect is being observed in the data. A negative temperature coefficient of solubility for actinides and rare earths in water would have important consequences for nuclear reactor safety and for the management of nuclear wastes

  16. Production and characterization of cowpea protein hydrolysate with optimum nitrogen solubility by enzymatic hydrolysis using pepsin.

    Science.gov (United States)

    Mune Mune, Martin Alain; Minka, Samuel René

    2017-06-01

    Cowpea is a source of low-cost and good nutritional quality protein for utilization in food formulations in replacement of animal proteins. Therefore it is necessary that cowpea protein exhibits good functionality, particularly protein solubility which affects the other functional properties. The objective of this study was to produce cowpea protein hydrolysate exhibiting optimum solubility by the adequate combination of hydrolysis parameters, namely time, solid/liquid ratio (SLR) and enzyme/substrate ratio (ESR), and to determine its functional properties and molecular characteristics. A Box-Behnken experimental design was used for the experiments, and a second-order polynomial to model the effects of hydrolysis time, SLR and ESR on the degree of hydrolysis and nitrogen solubility index. The optimum hydrolysis conditions of time 208.61 min, SLR 1/15 (w/w) and ESR 2.25% (w/w) yielded a nitrogen solubility of 75.71%. Protein breakdown and the peptide profile following enzymatic hydrolysis were evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and size exclusion chromatography. Cowpea protein hydrolysate showed higher oil absorption capacity, emulsifying activity and foaming ability compared with the concentrate. The solubility of cowpea protein hydrolysate was adequately optimized by response surface methodology, and the hydrolysate showed adequate functionality for use in food. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  17. Cleavage specificity analysis of six type II transmembrane serine proteases (TTSPs using PICS with proteome-derived peptide libraries.

    Directory of Open Access Journals (Sweden)

    Olivier Barré

    Full Text Available Type II transmembrane serine proteases (TTSPs are a family of cell membrane tethered serine proteases with unclear roles as their cleavage site specificities and substrate degradomes have not been fully elucidated. Indeed just 52 cleavage sites are annotated in MEROPS, the database of proteases, their substrates and inhibitors.To profile the active site specificities of the TTSPs, we applied Proteomic Identification of protease Cleavage Sites (PICS. Human proteome-derived database searchable peptide libraries were assayed with six human TTSPs (matriptase, matriptase-2, matriptase-3, HAT, DESC and hepsin to simultaneously determine sequence preferences on the N-terminal non-prime (P and C-terminal prime (P' sides of the scissile bond. Prime-side cleavage products were isolated following biotinylation and identified by tandem mass spectrometry. The corresponding non-prime side sequences were derived from human proteome databases using bioinformatics. Sequencing of 2,405 individual cleaved peptides allowed for the development of the family consensus protease cleavage site specificity revealing a strong specificity for arginine in the P1 position and surprisingly a lysine in P1' position. TTSP cleavage between R↓K was confirmed using synthetic peptides. By parsing through known substrates and known structures of TTSP catalytic domains, and by modeling the remainder, structural explanations for this strong specificity were derived.Degradomics analysis of 2,405 cleavage sites revealed a similar and characteristic TTSP family specificity at the P1 and P1' positions for arginine and lysine in unfolded peptides. The prime side is important for cleavage specificity, thus making these proteases unusual within the tryptic-enzyme class that generally has overriding non-prime side specificity.

  18. Synthetic peptides for antibody production

    NARCIS (Netherlands)

    Zegers, N.D.

    1995-01-01

    Synthetic peptides are useful tools for the generation of antibodies. The use of antibodies as specific reagents in inununochemical assays is widely applied. In this chapter, the application of synthetic peptides for the generation of antibodies is described. The different steps that lead to the

  19. Synthetic peptides for antibody production

    NARCIS (Netherlands)

    N.D. Zegers (Netty)

    1995-01-01

    textabstractSynthetic peptides are useful tools for the generation of antibodies. The use of antibodies as specific reagents in inununochemical assays is widely applied. In this chapter, the application of synthetic peptides for the generation of antibodies is described. The different steps

  20. Peptide radiopharmaceuticals in nuclear medicine

    International Nuclear Information System (INIS)

    Blok, D.; Vermeij, P.; Feitsma, R.I.J.; Pauwels, E.J.K.

    1999-01-01

    This article reviews the labelling of peptides that are recognised to be of interest for nuclear medicine or are the subject of ongoing nuclear medicine research. Applications and approaches to the labelling of peptide radiopharmaceuticals are discussed, and drawbacks in their development considered. (orig.)

  1. The remarkable stability of chimeric, sialic acid-derived alpha/delta-peptides in human blood plasma.

    Science.gov (United States)

    Saludes, Jonel P; Natarajan, Arutselvan; DeNardo, Sally J; Gervay-Hague, Jacquelyn

    2010-05-01

    Peptides are labile toward proteolytic enzymes, and structural modifications are often required to prolong their metabolic half-life and increase resistance. One modification is the incorporation of non-alpha-amino acids into the peptide to deter recognition by hydrolytic enzymes. We previously reported the synthesis of chimeric alpha/delta-peptides from glutamic acids (Glu) and the sialic acid derivative Neu2en. Conformational analyses revealed these constructs adopt secondary structures in water and may serve as conformational surrogates of polysialic acid. Polysialic acid is a tumor-associated polysaccharide and is correlated with cancer metastasis. Soluble polysialic acid is rapidly cleared from the blood limiting its potential for vaccine development. One motivation in developing structural surrogates of polysialic acid was to create constructs with increased bioavailability. Here, we report plasma stability profiles of Glu/Neu2en alpha/delta-peptides. DOTA was conjugated at the peptide N-termini by solid phase peptide synthesis, radiolabeled with (111)In, incubated in human blood plasma at 37 degrees C, and their degradation patterns monitored by cellulose acetate electrophoresis and radioactivity counting. Results indicate that these peptides exhibit a long half-life that is two- to three-orders of magnitude higher than natural alpha-peptides. These findings provide a viable platform for the synthesis of plasma stable, sialic acid-derived peptides that may find pharmaceutical application.

  2. A short synthetic peptide fragment of human C2ORF40 has therapeutic potential in breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chaoyang [Shandong Univ., Jinan (China); Zhang, Pengju [Shandong Univ., Jinan (China); Jiang, Anli [Shandong Univ., Jinan (China); Mao, Jian-Hua [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wei, Guangwei [Shandong Univ. School of Medicine, Jinan (China)

    2017-03-30

    C2ORF40 encodes a secreted protein which is cleaved to generate soluble peptides by proteolytic processing and this process is believed to be necessary for C2ORF40 to exert cell type specific biological activity. Here, we reported a short mimic peptide of human C2ORF40 acts potential therapeutic efficacy in human cancer cells in vitro and in vivo. We synthesized a short peptide of human C2ORF40, named C2ORF40 mimic peptide fragment and assessed its biological function on cancer cell growth, migration and tumorigenesis. Cell growth assay showed that C2ORF40 mimic peptide fragment significantly suppressed cell proliferation of breast and lung cancer cells. Moreover, C2ORF40 mimic peptide fragment significantly inhibited the migration and invasion of breast cancer cells. Furthermore, we showed that this peptide suppressed tumorigenesis in breast tumor xenograft model. Cell cycle assay indicated that the C2ORF40 mimic peptide fragment suppressed the growth of tumor cells through inducing mitotic phase arrest. In conclusion, our results firstly suggested that this short synthetic peptide of human C2ORF40 may be a candidate tumor therapeutic agent.

  3. The Equine PeptideAtlas

    DEFF Research Database (Denmark)

    Bundgaard, Louise; Jacobsen, Stine; Sørensen, Mette Aamand

    2014-01-01

    Progress in MS-based methods for veterinary research and diagnostics is lagging behind compared to the human research, and proteome data of domestic animals is still not well represented in open source data repositories. This is particularly true for the equine species. Here we present a first...... Equine PeptideAtlas encompassing high-resolution tandem MS analyses of 51 samples representing a selection of equine tissues and body fluids from healthy and diseased animals. The raw data were processed through the Trans-Proteomic Pipeline to yield high quality identification of proteins and peptides....... The current release comprises 24 131 distinct peptides representing 2636 canonical proteins observed at false discovery rates of 0.2% at the peptide level and 1.4% at the protein level. Data from the Equine PeptideAtlas are available for experimental planning, validation of new datasets, and as a proteomic...

  4. Vascular targeting with peptide libraries

    Energy Technology Data Exchange (ETDEWEB)

    Pasqualini, R. [La Jolla Cancer Research Center The Burnham Inst., La Jolla CA (United States)

    1999-06-01

    The authors have developed an 'in vivo' selection system in which phage capable of selective homing to different tissues are recovered from a phage display peptide library following intravenous administration. Using this strategy, they have isolate several organ and tumor-homing peptides. They have shown that each of those peptides binds of different receptors that are selectively expressed on the vasculature of the target tissue. The tumor-homing peptides bind to receptors that are up regulated in tumor angiogenic vasculature. Targeted delivery of doxorubicin to angiogenic vasculature using these peptides in animals models decrease toxicity and increased the therapeutic efficacy of the drug. Vascular targeting may facilitate the development of other treatment strategies that rely on inhibition of angio genesis and lead to advances to extend the potential for targeting of drugs, genes and radionuclides in the context of many diseases.

  5. Natriuretic peptides and cerebral hemodynamics

    DEFF Research Database (Denmark)

    Guo, Song; Barringer, Filippa; Zois, Nora Elisabeth

    2014-01-01

    Natriuretic peptides have emerged as important diagnostic and prognostic tools for cardiovascular disease. Plasma measurement of the bioactive peptides as well as precursor-derived fragments is a sensitive tool in assessing heart failure. In heart failure, the peptides are used as treatment...... in decompensated disease. In contrast, their biological effects on the cerebral hemodynamics are poorly understood. In this mini-review, we summarize the hemodynamic effects of the natriuretic peptides with a focus on the cerebral hemodynamics. In addition, we will discuss its potential implications in diseases...... where alteration of the cerebral hemodynamics plays a role such as migraine and acute brain injury including stroke. We conclude that a possible role of the peptides is feasible as evaluated from animal and in vitro studies, but more research is needed in humans to determine the precise response...

  6. Maize Bioactive Peptides against Cancer

    Science.gov (United States)

    Díaz-Gómez, Jorge L.; Castorena-Torres, Fabiola; Preciado-Ortiz, Ricardo E.; García-Lara, Silverio

    2017-06-01

    Cancer is one of the main chronic degenerative diseases worldwide. In recent years, consumption of whole-grain cereals and their derived food products has been associated with reduction risks of various types of cancer. Cereals main biomolecules includes proteins, peptides, and amino acids present in different quantities within the grain. The nutraceutical properties associated with peptides exerts biological functions that promote health and prevent this disease. In this review, we report the current status and advances on maize peptides regarding bioactive properties that have been reported such as antioxidant, antihypertensive, hepatoprotective, and anti-tumour activities. We also highlighted its biological potential through which maize bioactive peptides exert anti-cancer activity. Finally, we analyse and emphasize the possible areas of application for maize peptides.

  7. Rapid detection of peptide markers for authentication purposes in raw and cooked meat using ambient liquid extraction surface analysis mass spectrometry.

    Science.gov (United States)

    Montowska, Magdalena; Alexander, Morgan R; Tucker, Gregory A; Barrett, David A

    2014-10-21

    In this Article, our previously developed ambient LESA-MS methodology is implemented to analyze five types of thermally treated meat species, namely, beef, pork, horse, chicken, and turkey meat, to select and identify heat-stable and species-specific peptide markers. In-solution tryptic digests of cooked meats were deposited onto a polymer surface, followed by LESA-MS analysis and evaluation using multivariate data analysis and tandem electrospray MS. The five types of cooked meat were clearly discriminated using principal component analysis and orthogonal partial least-squares discriminant analysis. 23 heat stable peptide markers unique to species and muscle protein were identified following data-dependent tandem LESA-MS analysis. Surface extraction and direct ambient MS analysis of mixtures of cooked meat species was performed for the first time and enabled detection of 10% (w/w) of pork, horse, and turkey meat and 5% (w/w) of chicken meat in beef, using the developed LESA-MS/MS analysis. The study shows, for the first time, that ambient LESA-MS methodology displays specificity sufficient to be implemented effectively for the analysis of processed and complex peptide digests. The proposed approach is much faster and simpler than other measurement tools for meat speciation; it has potential for application in other areas of meat science or food production.

  8. Determination of soluble protein contents from RVNRL

    International Nuclear Information System (INIS)

    Wan Manshol Wan Zin; Nurulhuda Othman

    1996-01-01

    This project was carried out to determine the soluble protein contents on RVNRL film vulcanisates, with respect to the RVNRL storage time, gamma irradiation dose absorbed by the latex and the effect of different leaching time and leaching conditions. These three factors are important in the hope to determine the best possible mean of minimizing the soluble protein contents in products made from RVNRL. Within the nine months storage period employed in the study, the results show that, the longer the storage period the less the soluble protein extracted from the film samples. Gamma irradiation dose absorbed by the samples, between 5.3 kGy to 25.2 kGy seems to influence the soluble protein contents of the RVNRL films vulcanisates. The higher the dose the more was the soluble protein extracted from the film samples. At an absorbed dose of 5.3 kGy and 25.2 kGy, the soluble contents were 0. 198 mg/ml and 0.247 mg/ml respectively. At a fixed leaching temperature, the soluble proteins increases with leaching time and at a fixed leaching time, the soluble proteins increases with leaching temperature. ne highest extractable protein contents was determined at a leaching time of 10 minutes and leaching temperature of 90'C The protein analysis were done by using Modified Lowry Method

  9. Solubility Study of Curatives in Various Rubbers

    NARCIS (Netherlands)

    Guo, R.; Talma, Auke; Datta, Rabin; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

    2008-01-01

    The previous works on solubility of curatives in rubbers were mainly carried out in natural rubber. Not too much information available on dissimilar rubbers and this is important because most of the compounds today are blends of dissimilar rubbers. Although solubility can be expected to certain

  10. Solubility Products of M(II) - Carbonates

    International Nuclear Information System (INIS)

    Grauer, Rolf; Berner, Urs

    1999-01-01

    Many solubility data for M(II) carbonates commonly compiled in tables are contradictory and sometimes obviously wrong. The quality of such data has been evaluated based on the original publications and reliable solubility constants have been selected for the carbonates of Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb with the help of cross-comparisons. (author)

  11. Hansen Solubility Parameters for Octahedral Oligomeric Silsesquioxanes

    Science.gov (United States)

    2012-08-28

    1997, 80, 386-&. 5. Hansen, C. M. The three-dimensional solubility parameter -- key to paint component affinities I. J. Paint Technol. 1967, 39, 104...Chai, J.; Zhang, Q. X.; Han, D. X.; Niu, L. Synthesis and Application of Widely Soluble Graphene Sheets. Langmuir 2010, 26, 12314-12320. 12. Hansen, C

  12. A Colorful Solubility Exercise for Organic Chemistry

    Science.gov (United States)

    Shugrue, Christopher R.; Mentzen, Hans H., II; Linton, Brian R.

    2015-01-01

    A discovery chemistry laboratory has been developed for the introductory organic chemistry student to investigate the concepts of polarity, miscibility, solubility, and density. The simple procedure takes advantage of the solubility of two colored dyes in a series of solvents or solvent mixtures, and the diffusion of colors can be easily…

  13. Purification and use of E. coli peptide deformylase for peptide deprotection in chemoenzymatic peptide synthesis

    NARCIS (Netherlands)

    Di Toma, Claudia; Sonke, Theo; Quaedflieg, Peter J.; Janssen, Dick B.

    Peptide deformylases (PDFs) catalyze the removal of the formyl group from the N-terminal methionine residue in nascent polypeptide chains in prokaryotes. Its deformylation activity makes PDF an attractive candidate for the biocatalytic deprotection of formylated peptides that are used in

  14. Cathepsin-Mediated Cleavage of Peptides from Peptide Amphiphiles Leads to Enhanced Intracellular Peptide Accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Acar, Handan [Institute; Department; Samaeekia, Ravand [Institute; Department; Schnorenberg, Mathew R. [Institute; Department; Medical; Sasmal, Dibyendu K. [Institute; Huang, Jun [Institute; Tirrell, Matthew V. [Institute; Institute; LaBelle, James L. [Department

    2017-08-24

    Peptides synthesized in the likeness of their native interaction domain(s) are natural choices to target protein protein interactions (PPIs) due to their fidelity of orthostatic contact points between binding partners. Despite therapeutic promise, intracellular delivery of biofunctional peptides at concentrations necessary for efficacy remains a formidable challenge. Peptide amphiphiles (PAs) provide a facile method of intracellular delivery and stabilization of bioactive peptides. PAs consisting of biofunctional peptide headgroups linked to hydrophobic alkyl lipid-like tails prevent peptide hydrolysis and proteolysis in circulation, and PA monomers are internalized via endocytosis. However, endocytotic sequestration and steric hindrance from the lipid tail are two major mechanisms that limit PA efficacy to target intracellular PPIs. To address these problems, we have constructed a PA platform consisting of cathepsin-B cleavable PAs in which a selective p53-based inhibitory peptide is cleaved from its lipid tail within endosomes, allowing for intracellular peptide accumulation and extracellular recycling of the lipid moiety. We monitor for cleavage and follow individual PA components in real time using a resonance energy transfer (FRET)-based tracking system. Using this platform, components in real time using a Forster we provide a better understanding and quantification of cellular internalization, trafficking, and endosomal cleavage of PAs and of the ultimate fates of each component.

  15. Design of water-soluble, thiol-reactive polymers of controlled molecular weight: a novel multivalent scaffold

    Science.gov (United States)

    Carrillo, Alvaro; Gujraty, Kunal V.; Rai, Prakash R.; Kane, Ravi S.

    2005-07-01

    Multivalent molecules, i.e. scaffolds presenting multiple copies of a suitable ligand, constitute an emerging class of nanoscale therapeutics. We present a novel approach for the design of multivalent ligands, which allows the biofunctionalization of polymers with proteins or peptides in a controlled orientation. It consists of the synthesis of water-soluble, activated polymer scaffolds of controlled molecular weight, which can be biofunctionalized with various thiolated ligands in aqueous media under mild conditions. These polymers were synthesized by ring-opening metathesis polymerization (ROMP) and further modified to make them water-soluble. The incorporation of chloride groups activated the polymers to react with thiol-containing peptides or proteins, and the formation of multivalent ligands in aqueous media was demonstrated. This strategy represents a convenient route for synthesizing multivalent ligands of controlled dimensions and valency.

  16. Indomethacin solubility estimation in 1,4-dioxane + water mixtures by the extended hildebrand solubility approach

    Directory of Open Access Journals (Sweden)

    Miller A Ruidiaz

    2011-09-01

    Full Text Available Extended Hildebrand Solubility Approach (EHSA was successfully applied to evaluate the solubility of Indomethacin in 1,4-dioxane + water mixtures at 298.15 K. An acceptable correlation-performance of EHSA was found by using a regular polynomial model in order four of the W interaction parameter vs. solubility parameter of the mixtures (overall deviation was 8.9%. Although the mean deviation obtained was similar to that obtained directly by means of an empiric regression of the experimental solubility vs. mixtures solubility parameters, the advantages of EHSA are evident because it requires physicochemical properties easily available for drugs.

  17. Antibacterial and antiproliferative peptides in synbiotic yogurt-Release and stability during refrigerated storage.

    Science.gov (United States)

    Sah, B N P; Vasiljevic, T; McKechnie, S; Donkor, O N

    2016-06-01

    The search for alternative therapeutics is on the rise due to the extensive increase in bacterial resistance to various conventional antibiotics and side effects of conventional cancer therapies. Bioactive peptides released from natural sources such as dairy foods by lactic acid bacteria have received attention as a potential source of biotherapeutic peptides. However, liberation of peptides in yogurt depends on proteolytic activities of the cultures used. Thus, this research was conducted to establish generation of inhibitory peptides in yogurt against pathogenic bacteria and cancer cells during storage at 4°C for 28d. Water-soluble crude peptide extracts were prepared by high-speed centrifugation of plain and probiotic yogurts supplemented with or without pineapple peel powder (PPP). The inhibition zones against Escherichia coli and Staphylococcus aureus by PPP-fortified probiotic yogurt at 28d of storage were, respectively, 25.89 and 11.72mm in diameter, significantly higher than that of nonsupplemented control yogurts. Antiproliferative activity against HT29 colon cancer cells was also significantly higher in probiotic yogurt with PPP than in nonsupplemented probiotic yogurt. Overall, crude water-soluble peptide extracts of the probiotic yogurt with PPP possessed stronger inhibitory activities against bacteria and cancer cells than controls, and these activities were maintained during storage. However, activities were lowered substantially during in vitro gastrointestinal digestion. These findings support the possibility of utilizing dairy-derived bioactive peptides in the development of a superior alternative to the current generation of antibacterial and anticancer agents, as well as a functional ingredient in foods, nutraceuticals, and pharmaceuticals. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  18. Formation of active inclusion bodies induced by hydrophobic self-assembling peptide GFIL8.

    Science.gov (United States)

    Wang, Xu; Zhou, Bihong; Hu, Weike; Zhao, Qing; Lin, Zhanglin

    2015-06-16

    In the last few decades, several groups have observed that proteins expressed as inclusion bodies (IBs) in bacteria could still be biologically active when terminally fused to an appropriate aggregation-prone partner such as pyruvate oxidase from Paenibacillus polymyxa (PoxB). More recently, we have demonstrated that three amphipathic self-assembling peptides, an alpha helical peptide 18A, a beta-strand peptide ELK16, and a surfactant-like peptide L6KD, have properties that induce target proteins into active IBs. We have developed an efficient protein expression and purification approach for these active IBs by introducing a self-cleavable intein molecule. In this study, the self-assembling peptide GFIL8 (GFILGFIL) with only hydrophobic residues was analyzed, and this peptide effectively induced the formation of cytoplasmic IBs in Escherichia coli when terminally attached to lipase A and amadoriase II. The protein aggregates in cells were confirmed by transmission electron microscopy analysis and retained ~50% of their specific activities relative to the native counterparts. We constructed an expression and separation coupled tag (ESCT) by incorporating an intein molecule, the Mxe GyrA intein. Soluble target proteins were successfully released from active IBs upon cleavage of the intein between the GFIL8 tag and the target protein, which was mediated by dithiothreitol. A variant of GFIL8, GFIL16 (GFILGFILGFILGFIL), improved the ESCT scheme by efficiently eliminating interference from the soluble intein-GFIL8 molecule. The yields of target proteins at the laboratory scale were 3.0-7.5 μg/mg wet cell pellet, which is comparable to the yields from similar ESCT constructs using 18A, ELK16, or the elastin-like peptide tag scheme. The all-hydrophobic self-assembling peptide GFIL8 induced the formation of active IBs in E. coli when terminally attached to target proteins. GFIL8 and its variant GFIL16 can act as a "pull-down" tag to produce purified soluble proteins with

  19. Radiopharmaceutical development of radiolabelled peptides

    Energy Technology Data Exchange (ETDEWEB)

    Fani, Melpomeni; Maecke, Helmut R. [University Hospital Freiburg, Department of Nuclear Medicine, Freiburg (Germany)

    2012-02-15

    Receptor targeting with radiolabelled peptides has become very important in nuclear medicine and oncology in the past few years. The overexpression of many peptide receptors in numerous cancers, compared to their relatively low density in physiological organs, represents the molecular basis for in vivo imaging and targeted radionuclide therapy with radiolabelled peptide-based probes. The prototypes are analogs of somatostatin which are routinely used in the clinic. More recent developments include somatostatin analogs with a broader receptor subtype profile or with antagonistic properties. Many other peptide families such as bombesin, cholecystokinin/gastrin, glucagon-like peptide-1 (GLP-1)/exendin, arginine-glycine-aspartic acid (RGD) etc. have been explored during the last few years and quite a number of potential radiolabelled probes have been derived from them. On the other hand, a variety of strategies and optimized protocols for efficient labelling of peptides with clinically relevant radionuclides such as {sup 99m}Tc, M{sup 3+} radiometals ({sup 111}In, {sup 86/90}Y, {sup 177}Lu, {sup 67/68}Ga), {sup 64/67}Cu, {sup 18}F or radioisotopes of iodine have been developed. The labelling approaches include direct labelling, the use of bifunctional chelators or prosthetic groups. The choice of the labelling approach is driven by the nature and the chemical properties of the radionuclide. Additionally, chemical strategies, including modification of the amino acid sequence and introduction of linkers/spacers with different characteristics, have been explored for the improvement of the overall performance of the radiopeptides, e.g. metabolic stability and pharmacokinetics. Herein, we discuss the development of peptides as radiopharmaceuticals starting from the choice of the labelling method and the conditions to the design and optimization of the peptide probe, as well as some recent developments, focusing on a selected list of peptide families, including somatostatin

  20. Gene design, fusion technology and TEV cleavage conditions influence the purification of oxidized disulphide-rich venom peptides in Escherichia coli.

    Science.gov (United States)

    Sequeira, Ana Filipa; Turchetto, Jeremy; Saez, Natalie J; Peysson, Fanny; Ramond, Laurie; Duhoo, Yoan; Blémont, Marilyne; Fernandes, Vânia O; Gama, Luís T; Ferreira, Luís M A; Guerreiro, Catarina I P I; Gilles, Nicolas; Darbon, Hervé; Fontes, Carlos M G A; Vincentelli, Renaud

    2017-01-17

    Animal venoms are large, complex libraries of bioactive, disulphide-rich peptides. These peptides, and their novel biological activities, are of increasing pharmacological and therapeutic importance. However, recombinant expression of venom peptides in Escherichia coli remains difficult due to the significant number of cysteine residues requiring effective post-translational processing. There is also an urgent need to develop high-throughput recombinant protocols applicable to the production of reticulated peptides to enable efficient screening of their drug potential. Here, a comprehensive study was developed to investigate how synthetic gene design, choice of fusion tag, compartment of expression, tag removal conditions and protease recognition site affect levels of solubility of oxidized venom peptides produced in E. coli. The data revealed that expression of venom peptides imposes significant pressure on cysteine codon selection. DsbC was the best fusion tag for venom peptide expression, in particular when the fusion was directed to the bacterial periplasm. While the redox activity of DsbC was not essential to maximize expression of recombinant fusion proteins, redox activity did lead to higher levels of correctly folded target peptides. With the exception of proline, the canonical TEV protease recognition site tolerated all other residues at its C-terminus, confirming that no non-native residues, which might affect activity, need to be incorporated at the N-terminus of recombinant peptides for tag removal. This study reveals that E. coli is a convenient heterologous host for the expression of soluble and functional venom peptides. Using the optimal construct design, a large and diverse range of animal venom peptides were produced in the µM scale. These results open up new possibilities for the high-throughput production of recombinant disulphide-rich peptides in E. coli.

  1. Peptide-LNA oligonucleotide conjugates

    DEFF Research Database (Denmark)

    Astakhova, I Kira; Hansen, Lykke Haastrup; Vester, Birte

    2013-01-01

    properties, peptides were introduced into oligonucleotides via a 2'-alkyne-2'-amino-LNA scaffold. Derivatives of methionine- and leucine-enkephalins were chosen as model peptides of mixed amino acid content, which were singly and doubly incorporated into LNA/DNA strands using highly efficient copper......(i)-catalyzed azide-alkyne cycloaddition (CuAAC) "click" chemistry. DNA/RNA target binding affinity and selectivity of the resulting POCs were improved in comparison to LNA/DNA mixmers and unmodified DNA controls. This clearly demonstrates that internal attachment of peptides to oligonucleotides can significantly...

  2. New vasoactive peptides in cirrhosis

    DEFF Research Database (Denmark)

    Kimer, Nina; Goetze, Jens Peter; Bendtsen, Flemming

    2014-01-01

    BACKGROUND: Patients with cirrhosis have substantial circulatory imbalance between vasoconstrictive and vasodilating forces. The study of circulatory vasoactive peptides may provide important pathophysiological information. This study aimed to assess concentrations, organ extraction and relations...... to haemodynamic changes in the pro-peptides copeptin, proadrenomedullin and pro-atrial natriuretic peptide (proANP) in patients with cirrhosis. MATERIALS AND METHODS: Fifty-four cirrhotic patients and 15 controls were characterized haemodynamically during a liver vein catheterization. Copeptin, proadrenomedullin...... pressure (R=0·32, P0·31, Ppeptide is elevated in cirrhosis. Copeptin, proadrenomedullin and proANP are related to portal pressure and seem associated with systemic haemodynamics. These propeptides may...

  3. Serum Soluble Corin is Decreased in Stroke.

    Science.gov (United States)

    Peng, Hao; Zhu, Fangfang; Shi, Jijun; Han, Xiujie; Zhou, Dan; Liu, Yan; Zhi, Zhongwen; Zhang, Fuding; Shen, Yun; Ma, Juanjuan; Song, Yulin; Hu, Weidong

    2015-07-01

    Soluble corin was decreased in coronary heart disease. Given the connections between cardiac dysfunction and stroke, circulating corin might be a candidate marker of stroke risk. However, the association between circulating corin and stroke has not yet been studied in humans. Here, we aimed to examine the association in patients wtith stroke and community-based healthy controls. Four hundred eighty-one patients with ischemic stroke, 116 patients with hemorrhagic stroke, and 2498 healthy controls were studied. Serum soluble corin and some conventional risk factors of stroke were examined. Because circulating corin was reported to be varied between men and women, the association between serum soluble corin and stroke was evaluated in men and women, respectively. Patients with ischemic and hemorrhagic stroke had a significantly lower level of serum soluble corin than healthy controls in men and women (all P values, stroke than men in the highest quartile. Women in the lowest quartile of serum soluble corin were also more likely to have ischemic (OR, 3.10; 95% confidence interval, 1.76-5.44) and hemorrhagic (OR, 8.54; 95% confidence interval, 2.35-31.02) stroke than women in the highest quartile. ORs of ischemic and hemorrhagic stroke were significantly increased with the decreasing levels of serum soluble corin in men and women (all P values for trend, stroke compared with healthy controls. Our findings raise the possibility that serum soluble corin may have a pathogenic role in stroke. © 2015 American Heart Association, Inc.

  4. Solubilities of uranium for TILA-99

    International Nuclear Information System (INIS)

    Ollila, K.; Ahonen, L.

    1998-11-01

    This report presents the evaluation of the uranium solubilities in the reference waters of TILA-99. The behaviour of uranium has been discussed separately in the near-field and far-field conditions. The bentonite/groundwater interactions have been considered in the compositions of the fresh and saline near-field reference waters. The far-field groundwaters' compositions include fresh, brackish, saline and very saline, almost brine-type compositions. The pH and redox conditions, as the main parameters affecting the solubilities, are considered. A literature study was made in order to obtain information on the recent dissolution and leaching experiments of UO 2 and spent fuel. The latest literature includes studies on UO 2 solubility under anoxic conditions, in which the methods for simulating the reducing conditions of deep groundwater have been improved. Studies on natural uraninite and its alteration products give a valuable insight into the long-term behaviour of spent fuel. Also the solubility equilibria for some relevant poorly known uranium minerals have been determined. The solubilities of the selected solubility-limiting phases were calculated using the geochemical code, EQ3/6. The NEA database for uranium was the basis for the modelling. The recently extended and updated SR '97 database was used for comparison. The solubility products for uranophane were taken from the latest literature. The recommended values for solubilities were given after a comparison between the calculated solubilities, experimental information and measured concentrations in natural groundwaters. The experiments include several UO 2 dissolution studies in synthetic groundwaters with compositions close to the reference groundwaters. (author)

  5. Solubilities of uranium for TILA-99

    Energy Technology Data Exchange (ETDEWEB)

    Ollila, K. [VTT Chemical Technology, Espoo (Finland); Ahonen, L. [Geological Survey of Finland, Espoo (Finland)

    1998-11-01

    This report presents the evaluation of the uranium solubilities in the reference waters of TILA-99. The behaviour of uranium has been discussed separately in the near-field and far-field conditions. The bentonite/groundwater interactions have been considered in the compositions of the fresh and saline near-field reference waters. The far-field groundwaters` compositions include fresh, brackish, saline and very saline, almost brine-type compositions. The pH and redox conditions, as the main parameters affecting the solubilities, are considered. A literature study was made in order to obtain information on the recent dissolution and leaching experiments of UO{sub 2} and spent fuel. The latest literature includes studies on UO{sub 2} solubility under anoxic conditions, in which the methods for simulating the reducing conditions of deep groundwater have been improved. Studies on natural uraninite and its alteration products give a valuable insight into the long-term behaviour of spent fuel. Also the solubility equilibria for some relevant poorly known uranium minerals have been determined. The solubilities of the selected solubility-limiting phases were calculated using the geochemical code, EQ3/6. The NEA database for uranium was the basis for the modelling. The recently extended and updated SR `97 database was used for comparison. The solubility products for uranophane were taken from the latest literature. The recommended values for solubilities were given after a comparison between the calculated solubilities, experimental information and measured concentrations in natural groundwaters. The experiments include several UO{sub 2} dissolution studies in synthetic groundwaters with compositions close to the reference groundwaters. (author) 81 refs.

  6. Isolation and structural analysis of antihypertensive peptides that exist naturally in Gouda cheese.

    Science.gov (United States)

    Saito, T; Nakamura, T; Kitazawa, H; Kawai, Y; Itoh, T

    2000-07-01

    Seven kinds of ripened cheeses (8-mo-aged and 24-mo-aged Gouda, Emmental, Blue, Camembert, Edam, and Havarti) were homogenized with distilled water, and water-soluble peptides were prepared by C-18 hydrophobic chromatography. The inhibitory activity to angiotensin I-converting enzyme and decrease in the systolic blood pressure in spontaneously hypertensive rats were measured before and after oral administration of each peptide sample. The strongest depressive effect in the systolic blood pressure (-24.7 mm Hg) and intensive inhibitory activity to angiotensin I-converting enzyme (75.7%) were detected in the peptides from 8-mo-aged Gouda cheese. Four peptides were isolated by HPLC with reverse-phase and gel filtration modes. Their chemical structures and origins, clarified by combination analyses of protein sequencing, amino acid composition, and mass spectrometry, were as follows: peptide A, Arg-Pro-Lys-His-Pro-Ile-Lys-His-Gln [alpha(s1)-casein (CN), B-8P; f 1-9]; peptide B, Arg-Pro-Lys-His-Pro-Ile-Lys-His-Gln-Gly-Leu-Pro-Gln (alpha(s1)-CN, B-8P; f 1-13); peptide F, Tyr-Pro-Phe-Pro-Gly-Pro-Ile-Pro-Asn (beta-CN, A2-5P; f 60-68); and peptide G, Met-Pro-Phe-Pro-Lys-Tyr-Pro-Val-Gln-Pro-Phe (beta-CN, A2-5P; f 109-119). Peptides A and F, which were chemically synthesized, showed potent angiotensin I-converting enzyme inhibitory activity with little antihypertensive effects.

  7. Generation of functional HLA-DR*1101 tetramers receptive for loading with pathogen or tumour derived synthetic peptides

    Directory of Open Access Journals (Sweden)

    Protti Maria

    2005-12-01

    Full Text Available Abstract Background MHC class I-peptide tetramers are currently utilised to characterize CD8+ T cell responses at single cell level. The generation and use of MHC class II tetramers to study antigen-specific CD4+ T cells appears less straightforward. Most MHC class II tetramers are produced with a homogeneously built-in peptide, reducing greatly their flexibility of use. We attempted the generation of "empty" functional HLA-DR*1101 tetramers, receptive for loading with synthetic peptides by incubation. No such reagent is in fact available for this HLA-DR allele, one of the most frequent in the Caucasian population. Results We compared soluble MHC class II-immunoglobulin fusion proteins (HLA-DR*1101-Ig with soluble MHC class II protein fused with an optimised Bir site for enzymatic biotynilation (HLA-DR*1101-Bir, both produced in insect cells. The molecules were multimerised by binding fluorochrome-protein A or fluorochrome-streptavidin, respectively. We find that HLA-DR*1101-Bir molecules are superior to the HLA-DR*1101-Ig ones both in biochemical and functional terms. HLA-DR*1101-Bir molecules can be pulsed with at least three different promiscuous peptide epitopes, derived from Tetanus Toxoid, influenza HA and the tumour associated antigen MAGE-3 respectively, to stain specific CD4+ T cells. Both staining temperature and activation state of CD4+ T cells are critical for the binding of peptide-pulsed HLA-DR*1101-Bir to the cognate TCR. Conclusion It is therefore possible to generate a soluble recombinant HLA-DR*1101 backbone that is receptive for loading with different peptides to stain specific CD4+ T cells. As shown for other HLA-DR alleles, we confirm that not all the strategies to produce soluble HLA-DR*1101 multimers are equivalent.

  8. Solubility limited radionuclide transport through geologic media

    International Nuclear Information System (INIS)

    Muraoka, Susumu; Iwamoto, Fumio; Pigford, T.H.

    1980-11-01

    Prior analyses for the migration of radionuclides neglect solubility limits of resolved radionuclide in geologic media. But actually some of the actinides may appear in chemical forms of very low solubility. In the present report we have proposed the migration model with no decay parents in which concentration of radionuclide is limited in concentration of solubility in ground water. In addition, the analytical solutions of the space-time-dependent concentration are presented in the case of step release, band release and exponential release. (author)

  9. Residual nilpotence and residual solubility of groups

    International Nuclear Information System (INIS)

    Mikhailov, R V

    2005-01-01

    The properties of the residual nilpotence and the residual solubility of groups are studied. The main objects under investigation are the class of residually nilpotent groups such that each central extension of these groups is also residually nilpotent and the class of residually soluble groups such that each Abelian extension of these groups is residually soluble. Various examples of groups not belonging to these classes are constructed by homological methods and methods of the theory of modules over group rings. Several applications of the theory under consideration are presented and problems concerning the residual nilpotence of one-relator groups are considered.

  10. Water Soluble Polymers for Pharmaceutical Applications

    Directory of Open Access Journals (Sweden)

    Veeran Gowda Kadajji

    2011-11-01

    Full Text Available Advances in polymer science have led to the development of novel drug delivery systems. Some polymers are obtained from natural resources and then chemically modified for various applications, while others are chemically synthesized and used. A large number of natural and synthetic polymers are available. In the present paper, only water soluble polymers are described. They have been explained in two categories (1 synthetic and (2 natural. Drug polymer conjugates, block copolymers, hydrogels and other water soluble drug polymer complexes have also been explained. The general properties and applications of different water soluble polymers in the formulation of different dosage forms, novel delivery systems and biomedical applications will be discussed.

  11. Molecular Thermodynamic Modeling of Mixed Solvent Solubility

    DEFF Research Database (Denmark)

    Ellegaard, Martin Dela; Abildskov, Jens; O’Connell, John P.

    2010-01-01

    A method based on statistical mechanical fluctuation solution theory for composition derivatives of activity coefficients is employed for estimating dilute solubilities of 11 solid pharmaceutical solutes in nearly 70 mixed aqueous and nonaqueous solvent systems. The solvent mixtures range from...... nearly ideal to strongly nonideal. The database covers a temperature range from 293 to 323 K. Comparisons with available data and other existing solubility methods show that the method successfully describes a variety of observed mixed solvent solubility behaviors using solute−solvent parameters from...

  12. Characterization of synthetic peptides by mass spectrometry

    DEFF Research Database (Denmark)

    Prabhala, Bala Krishna; Mirza, Osman Asghar; Højrup, Peter

    2015-01-01

    Mass spectrometry (MS) is well suited for analysis of the identity and purity of synthetic peptides. The sequence of a synthetic peptide is most often known, so the analysis is mainly used to confirm the identity and purity of the peptide. Here, simple procedures are described for MALDI......-TOF-MS and LC-MS of synthetic peptides....

  13. Cleaved thioredoxin fusion protein enables the crystallization of poorly soluble ERα in complex with synthetic ligands

    International Nuclear Information System (INIS)

    Cura, Vincent; Gangloff, Monique; Eiler, Sylvia; Moras, Dino; Ruff, Marc

    2007-01-01

    A new crystallization strategy: the presence of cleaved thioredoxin fusion is critical for crystallization of the estrogen nuclear receptor ligand binding domain in complex with synthetic ligands. This novel technique should be regarded as an interesting alternative for crystallization of difficult proteins. The ligand-binding domain (LBD) of human oestrogen receptor α was produced in Escherichia coli as a cleavable thioredoxin (Trx) fusion in order to improve solubility. Crystallization trials with either cleaved and purified LBD or with the purified fusion protein both failed to produce crystals. In another attempt, Trx was not removed from the LBD after endoproteolytic cleavage and its presence promoted nucleation and subsequent crystal growth, which allowed the structure determination of two different LBD–ligand–coactivator peptide complexes at 2.3 Å resolution. This technique is likely to be applicable to other low-solubility proteins

  14. Marine Peptides: Bioactivities and Applications

    Directory of Open Access Journals (Sweden)

    Randy Chi Fai Cheung

    2015-06-01

    Full Text Available Peptides are important bioactive natural products which are present in many marine species. These marine peptides have high potential nutraceutical and medicinal values because of their broad spectra of bioactivities. Their antimicrobial, antiviral, antitumor, antioxidative, cardioprotective (antihypertensive, antiatherosclerotic and anticoagulant, immunomodulatory, analgesic, anxiolytic anti-diabetic, appetite suppressing and neuroprotective activities have attracted the attention of the pharmaceutical industry, which attempts to design them for use in the treatment or prevention of various diseases. Some marine peptides or their derivatives have high commercial values and had reached the pharmaceutical and nutraceutical markets. A large number of them are already in different phases of the clinical and preclinical pipeline. This review highlights the recent research in marine peptides and the trends and prospects for the future, with special emphasis on nutraceutical and pharmaceutical development into marketed products.

  15. Cardioprotective peptides from marine sources.

    Science.gov (United States)

    Harnedy, Padraigín A; FitzGerald, Richard J

    2013-05-01

    Elevated blood pressure or hypertension is one of the fastest growing health problems worldwide. Although the etiology of essential hypertension has a genetic component, dietary factors play an important role. With the high costs and adverse side-effects associated with synthetic antihypertensive drugs and the awareness of the link between diet and health there has been increased focus on identification of food components that may contribute to cardiovascular health. In recent years special interest has been paid to the cardioprotective activity of peptides derived from food proteins including marine proteins. These peptides are latent within the sequence of the parent protein and only become active when released by proteolytic digestion during gastrointestinal digestion or through food processing. Current data on antihypertensive activity of marine-derived protein hydrolysates/peptides in animal and human studies is reviewed herein. Furthermore, products containing protein hydrolysates/peptides from marine origin with antihypertensive effects are discussed.

  16. Antimicrobial peptides from Capsicum sp.

    African Journals Online (AJOL)

    ajl yemi

    2011-12-30

    Dec 30, 2011 ... Key words: Antimicrobial peptides, Capsicum sp, Capsicum chinense, chili pepper, agronomical options, ..... of this human activity is resumed by the simple phrase: produce .... It will be interesting to scale the AMPs extraction.

  17. Production and characterization of peptide antibodies

    DEFF Research Database (Denmark)

    Trier, Nicole Hartwig; Hansen, Paul Robert; Houen, Gunnar

    2012-01-01

    Proteins are effective immunogens for generation of antibodies. However, occasionally the native protein is known but not available for antibody production. In such cases synthetic peptides derived from the native protein are good alternatives for antibody production. These peptide antibodies...... are powerful tools in experimental biology and are easily produced to any peptide of choice. A widely used approach for production of peptide antibodies is to immunize animals with a synthetic peptide coupled to a carrier protein. Very important is the selection of the synthetic peptide, where factors......, including solid-phase peptide-carrier conjugation and peptide-carrier conjugation in solution. Upon immunization, adjuvants such as Al(OH)(3) are added together with the immunogenic peptide-carrier conjugate, which usually leads to high-titred antisera. Following immunization and peptide antibody...

  18. Inhibition of peptide aggregation by means of enzymatic phosphorylation

    Directory of Open Access Journals (Sweden)

    Kristin Folmert

    2016-11-01

    Full Text Available As is the case in numerous natural processes, enzymatic phosphorylation can be used in the laboratory to influence the conformational populations of proteins. In nature, this information is used for signal transduction or energy transfer, but has also been shown to play an important role in many diseases like tauopathies or diabetes. With the goal of determining the effect of phosphorylation on amyloid fibril formation, we designed a model peptide which combines structural characteristics of α-helical coiled-coils and β-sheets in one sequence. This peptide undergoes a conformational transition from soluble structures into insoluble amyloid fibrils over time and under physiological conditions and contains a recognition motif for PKA (cAMP-dependent protein kinase that enables enzymatic phosphorylation. We have analyzed the pathway of amyloid formation and the influence of enzymatic phosphorylation on the different states along the conformational transition from random-coil to β-sheet-rich oligomers to protofilaments and on to insoluble amyloid fibrils, and we found a remarkable directing effect from β-sheet-rich structures to unfolded structures in the initial growth phase, in which small oligomers and protofilaments prevail if the peptide is phosphorylated.

  19. High pressure treatment of brine enhanced pork affects endopeptidase activity, protein solubility, and peptide formation

    DEFF Research Database (Denmark)

    Grossi, Alberto Blak; Gkarane, Vasiliki; Otte, Jeanette Anita Held

    2012-01-01

    at 600 MPa following storage at 2 °C for up to 8 weeks. In this report a novel protocol for SDS gelatin zymography was established, and an increase of cathepsin B and L activity after HP treatment was shown followed by a decrease during storage. No calpain activity was detected following HP treatment. HP...

  20. Proteome array identification of bioactive soluble proteins/peptides in matrigel; relevance to stem cell responses

    Science.gov (United States)

    Matrigel and similar commercial products are extracts of the Engelbreth-Holm-Swarm sarcoma that provide a basement-membrane-like attachment factor or gel that is used to grow cells on or in. To ascertain further what proteins may be present in Matrigel, besides its major basement-membrane constitue...

  1. Peptides and proteins

    Energy Technology Data Exchange (ETDEWEB)

    Bachovchin, W.W.; Unkefer, C.J.

    1994-12-01

    Advances in magnetic resonance and vibrational spectroscopy make it possible to derive detailed structural information about biomolecular structures in solution. These techniques are critically dependent on the availability of labeled compounds. For example, NMR techniques used today to derive peptide and protein structures require uniformity {sup 13}C-and {sup 15}N-labeled samples that are derived biosynthetically from (U-6-{sup 13}C) glucose. These experiments are possible now because, during the 1970s, the National Stable Isotope Resource developed algal methods for producing (U-6-{sup 13}C) glucose. If NMR techniques are to be used to study larger proteins, we will need sophisticated labelling patterns in amino acids that employ a combination of {sup 2}H, {sup 13}C, and {sup 15}N labeling. The availability of these specifically labeled amino acids requires a renewed investment in new methods for chemical synthesis of labeled amino acids. The development of new magnetic resonance or vibrational techniques to elucidate biomolecular structure will be seriously impeded if we do not see rapid progress in labeling technology. Investment in labeling chemistry is as important as investment in the development of advanced spectroscopic tools.

  2. Solubility of carbohydrates in heavy water.

    Science.gov (United States)

    Cardoso, Marcus V C; Carvalho, Larissa V C; Sabadini, Edvaldo

    2012-05-15

    The solubility of several mono-(glucose and xylose), di-(sucrose and maltose), tri-(raffinose) and cyclic (α-cyclodextrin) saccharides in H(2)O and in D(2)O were measured over a range of temperatures. The solution enthalpies for the different carbohydrates in the two solvents were determined using the vant' Hoff equation and the values in D(2)O are presented here for the first time. Our findings indicate that the replacement of H(2)O by D(2)O remarkably decreases the solubilities of the less soluble carbohydrates, such as maltose, raffinose and α-cyclodextrin. On the other hand, the more soluble saccharides, glucose, xylose, and sucrose, are practically insensitive to the H/D replacement in water. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Enhancement of Solubility and Bioavailability of Candesartan ...

    African Journals Online (AJOL)

    Purpose: To enhance the otherwise poor solubility and bioavailability of candesartan cilexetil (CDS). Methods: This ... PEG 6000-based solid dispersions showed 1st order drug release kinetics. ..... the liver due to quercetin's inhibitory effect on.

  4. An Introduction to the Understanding of Solubility.

    Science.gov (United States)

    Letcher, Trevor M.; Battino, Rubin

    2001-01-01

    Explores different solubility processes and related issues, including the second law of thermodynamics and ideal mixtures, real liquids, intermolecular forces, and solids in liquids or gases in liquids. (Contains 22 references.) (ASK)

  5. Progress in the research of neptunium solubility

    International Nuclear Information System (INIS)

    Jiang Tao; Liu Yongye; Yao Jun

    2012-01-01

    237 Np is considered a possible long-term potential threat for environment, because of its long half-life, high toxicity and its mobile nature under aerobic conditions due to the high chemical stability of its pentavalent state. Therefore 237 Np is considered as one of high-level radioactive waste and need to be disposed in deep geologic disposal repository. The dissolution behavior is an important aspect of migration research. The solubility is considered very important for high level waste geological disposal safety and environmental evaluation. The solubility determines the maximum concentration of the discharge, and then it is initial concentration of the radionuclides migration to the environment. The solubility impact directly on radionuclides migration in host rock, and can be used to predict the concentration and speciation of radionuclides in groundwater around disposal sites many years later. This paper focused on research results of the solubility, some proposals for Np dissolution chemistry research were also been suggested. (authors)

  6. Matrix-assisted peptide synthesis on nanoparticles.

    Science.gov (United States)

    Khandadash, Raz; Machtey, Victoria; Weiss, Aryeh; Byk, Gerardo

    2014-09-01

    We report a new method for multistep peptide synthesis on polymeric nanoparticles of differing sizes. Polymeric nanoparticles were functionalized via their temporary embedment into a magnetic inorganic matrix that allows multistep peptide synthesis. The matrix is removed at the end of the process for obtaining nanoparticles functionalized with peptides. The matrix-assisted synthesis on nanoparticles was proved by generating various biologically relevant peptides. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

  7. In vitro production and antifungal activity of peptide ABP-dHC-cecropin A.

    Science.gov (United States)

    Zhang, Jiaxin; Movahedi, Ali; Xu, Junjie; Wang, Mengyang; Wu, Xiaolong; Xu, Chen; Yin, Tongming; Zhuge, Qiang

    2015-04-10

    The antimicrobial peptide ABP-dHC-cecropin A is a small cationic peptide with potent activity against a wide range of bacterial species. Evidence of antifungal activity has also been suggested; however, testing of this peptide has been limited due to the low expression of cecropin proteins in Escherichia coli. To improve expression of this peptide in E. coli, ABP-dHC-cecropin A was cloned into a pSUMO vector and transformed into E. coli, resulting in the production of a pSUMO-ABP-dHC-cecropin A fusion protein. The soluble form of this protein was then purified by Ni-IDA chromatography, yielding a total of 496-mg protein per liter of fermentation culture. The SUMO-ABP-dHC-cecropin A fusion protein was then cleaved using a SUMO protease and re-purified by Ni-IDA chromatography, yielding a total of 158-mg recombinant ABP-dHC-cecropin A per liter of fermentation culture at a purity of ≥94%, the highest yield reported to date. Antifungal activity assays performed using this purified recombinant peptide revealed strong antifungal activity against both Candida albicans and Neurospora crassa, as well as Rhizopus, Fusarium, Alternaria, and Mucor species. Combined with previous analyses demonstrating strong antibacterial activity against a number of important bacterial pathogens, these results confirm the use of ABP-dHC-cecropin A as a broad-spectrum antimicrobial peptide, with significant therapeutic potential. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Material Binding Peptides for Nanotechnology

    Directory of Open Access Journals (Sweden)

    Urartu Ozgur Safak Seker

    2011-02-01

    Full Text Available Remarkable progress has been made to date in the discovery of material binding peptides and their utilization in nanotechnology, which has brought new challenges and opportunities. Nowadays phage display is a versatile tool, important for the selection of ligands for proteins and peptides. This combinatorial approach has also been adapted over the past decade to select material-specific peptides. Screening and selection of such phage displayed material binding peptides has attracted great interest, in particular because of their use in nanotechnology. Phage display selected peptides are either synthesized independently or expressed on phage coat protein. Selected phage particles are subsequently utilized in the synthesis of nanoparticles, in the assembly of nanostructures on inorganic surfaces, and oriented protein immobilization as fusion partners of proteins. In this paper, we present an overview on the research conducted on this area. In this review we not only focus on the selection process, but also on molecular binding characterization and utilization of peptides as molecular linkers, molecular assemblers and material synthesizers.

  9. Biophysical characterization data on Aβ soluble oligomers produced through a method enabling prolonged oligomer stability and biological buffer conditions

    Directory of Open Access Journals (Sweden)

    Amanda C. Crisostomo

    2015-09-01

    Aβ1-40 soluble oligomers are produced that are suitable for biophysical studies requiring sufficient transient stability to exist in their “native” conformation in biological phosphate-saline buffers for extended periods of time. The production involves an initial preparation of highly monomeric Aβ in a phosphate saline buffer that transitions to fibrils and oligomers through time incubation alone, without added detergents or non-aqueous chemicals. This criteria ensures that the only difference between initial monomeric Aβ reactant and subsequent Aβ oligomer products is their degree of peptide assembly. A number of chemical and biophysical methods were used to characterize the monomeric reactants and soluble oligomer and amyloid fibril products, including chemical cross-linking, Western blots, fraction solubility, thioflvain T binding, size exclusion chromatography, transmission electron micrscopy, circular dichroism spectroscopy, and fluorescence resonance energy transfer.

  10. Solubility Products of M(II) - Carbonates

    Energy Technology Data Exchange (ETDEWEB)

    Grauer, Rolf; Berner, Urs [ed.

    1999-01-01

    Many solubility data for M(II) carbonates commonly compiled in tables are contradictory and sometimes obviously wrong. The quality of such data has been evaluated based on the original publications and reliable solubility constants have been selected for the carbonates of Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb with the help of cross-comparisons. (author) translated from a PSI internal report written in German in 1994 (TM-44-94-05). 5 figs., 1 tab., 68 refs.

  11. Hydrogen solubility in polycrystalline - and nonocrystalline niobium

    International Nuclear Information System (INIS)

    Ishikawa, T.T.; Silva, J.R.G. da

    1981-01-01

    Hydrogen solubility in polycrystalline and monocrystalline niobium was measured in the range 400 0 C to 1000 0 C at one atmosphere hydrogen partial pressure. The experimental technique consists of saturation of the solvent metal with hydrogen, followed by quenching and analysis of the solid solution. It is presented solubility curves versus reciprocal of the absolute doping temperature, associated with their thermodynamical equation. (Author) [pt

  12. Respiratory carcinogenicity assessment of soluble nickel compounds.

    OpenAIRE

    Oller, Adriana R

    2002-01-01

    The many chemical forms of nickel differ in physicochemical properties and biological effects. Health assessments for each main category of nickel species are needed. The carcinogenicity assessment of water-soluble nickel compounds has proven particularly difficult. Epidemiologic evidence indicates an association between inhalation exposures to nickel refinery dust containing soluble nickel compounds and increased risk of respiratory cancers. However, the nature of this association is unclear...

  13. Correlation of Helium Solubility in Liquid Nitrogen

    Science.gov (United States)

    VanDresar, Neil T.; Zimmerli, Gregory A.

    2012-01-01

    A correlation has been developed for the equilibrium mole fraction of soluble gaseous helium in liquid nitrogen as a function of temperature and pressure. Experimental solubility data was compiled and provided by National Institute of Standards and Technology (NIST). Data from six sources was used to develop a correlation within the range of 0.5 to 9.9 MPa and 72.0 to 119.6 K. The relative standard deviation of the correlation is 6.9 percent.

  14. Flanking signal and mature peptide residues influence signal peptide cleavage

    Directory of Open Access Journals (Sweden)

    Ranganathan Shoba

    2008-12-01

    Full Text Available Abstract Background Signal peptides (SPs mediate the targeting of secretory precursor proteins to the correct subcellular compartments in prokaryotes and eukaryotes. Identifying these transient peptides is crucial to the medical, food and beverage and biotechnology industries yet our understanding of these peptides remains limited. This paper examines the most common type of signal peptides cleavable by the endoprotease signal peptidase I (SPase I, and the residues flanking the cleavage sites of three groups of signal peptide sequences, namely (i eukaryotes (Euk (ii Gram-positive (Gram+ bacteria, and (iii Gram-negative (Gram- bacteria. Results In this study, 2352 secretory peptide sequences from a variety of organisms with amino-terminal SPs are extracted from the manually curated SPdb database for analysis based on physicochemical properties such as pI, aliphatic index, GRAVY score, hydrophobicity, net charge and position-specific residue preferences. Our findings show that the three groups share several similarities in general, but they display distinctive features upon examination in terms of their amino acid compositions and frequencies, and various physico-chemical properties. Thus, analysis or prediction of their sequences should be separated and treated as distinct groups. Conclusion We conclude that the peptide segment recognized by SPase I extends to the start of the mature protein to a limited extent, upon our survey of the amino acid residues surrounding the cleavage processing site. These flanking residues possibly influence the cleavage processing and contribute to non-canonical cleavage sites. Our findings are applicable in defining more accurate prediction tools for recognition and identification of cleavage site of SPs.

  15. Hydrothermal solubility of uraninite. Final technical report

    International Nuclear Information System (INIS)

    Parks, G.A.; Pohl, D.C.

    1985-01-01

    Experimental measurements of the solubility of UO 2 from 100 to 300 0 C under 500 bars H 2 , in NaCl solutions at pH from 1 to 8 do not agree with solubilities calculated using existing thermodynamic databases. For pH 2 (hyd) has precipitated and is controlling solubility. For pH > 8, solubilities at all temperatures are much lower than predicted, suggesting that the U(OH)/sub delta/ - complex is much weaker than predicted. Extrapolated to 25 0 C, high pH solubility agrees within experimental error with the upper limit suggested by Ryan and Rai (1983). In the pH range 2 to 6, solubilities are up to three orders of magnitude lower than predicted for temperatures exceeding 200 0 C and up to two orders higher than predicted at lower temperatures. pH dependence in this region is negligible suggesting that U(OH) 4 (aq) predominates, thus the stability of this species is higher than presently estimated at low temperatures, but the enthalpy of solution is smaller. A low maximum observed near pH approx. =3 is presently unexplained. 40 refs., 16 figs., 12 tabs

  16. Uranium solubility and speciation in ground water

    International Nuclear Information System (INIS)

    Ollila, K.

    1985-04-01

    The purpose of this study has been to assess the solubility and possible species of uranium in groundwater at the disposal conditions of spent fuel. The effects of radiolysis and bentonite are considered. The assessment is based on the theoretical calculations found in the literature. The Finnish experimental results are included. The conservative estimate for uranium solubility under the oxidizing conditions caused by alpha radiolysis is based on the oxidation of uranium to the U(VI) state and formation of carbonate complex. For the groundwater with the typical carbonate content of 275 mg/l and the high carbonate content of 485 mg/l due to bentonite, the solubility values of 360 mg u/l and 950 mg U/l, are obtained, respectively. The experimental results predict considerably lower values, 0.5-20 mg U/l. The solubility of uranium under the undisturbed reducing conditions may be calculated based on the hydrolysis, carbonate complexation and redox reactions. The results vary considerably depending on the thermodynamic data used. The wide ranges of the most important groundwater parameters are seen in the solubility values. The experimental results show the same trends. As a conservative value for the solubility in reducing groundwater 50-500 μg U/l is estimated. (author)

  17. Sibutramine characterization and solubility, a theoretical study

    Science.gov (United States)

    Aceves-Hernández, Juan M.; Nicolás Vázquez, Inés; Hinojosa-Torres, Jaime; Penieres Carrillo, Guillermo; Arroyo Razo, Gabriel; Miranda Ruvalcaba, René

    2013-04-01

    Solubility data from sibutramine (SBA) in a family of alcohols were obtained at different temperatures. Sibutramine was characterized by using thermal analysis and X-ray diffraction technique. Solubility data were obtained by the saturation method. The van't Hoff equation was used to obtain the theoretical solubility values and the ideal solvent activity coefficient. No polymorphic phenomena were found from the X-ray diffraction analysis, even though this compound is a racemic mixture of (+) and (-) enantiomers. Theoretical calculations showed that the polarisable continuum model was able to reproduce the solubility and stability of sibutramine molecule in gas phase, water and a family of alcohols at B3LYP/6-311++G (d,p) level of theory. Dielectric constant, dipolar moment and solubility in water values as physical parameters were used in those theoretical calculations for explaining that behavior. Experimental and theoretical results were compared and good agreement was obtained. Sibutramine solubility increased from methanol to 1-octanol in theoretical and experimental results.

  18. Peptides and Anti-peptide Antibodies for Small and Medium Scale Peptide and Anti-peptide Affinity Microarrays: Antigenic Peptide Selection, Immobilization, and Processing.

    Science.gov (United States)

    Zhang, Fan; Briones, Andrea; Soloviev, Mikhail

    2016-01-01

    This chapter describes the principles of selection of antigenic peptides for the development of anti-peptide antibodies for use in microarray-based multiplex affinity assays and also with mass-spectrometry detection. The methods described here are mostly applicable to small to medium scale arrays. Although the same principles of peptide selection would be suitable for larger scale arrays (with 100+ features) the actual informatics software and printing methods may well be different. Because of the sheer number of proteins/peptides to be processed and analyzed dedicated software capable of processing all the proteins and an enterprise level array robotics may be necessary for larger scale efforts. This report aims to provide practical advice to those who develop or use arrays with up to ~100 different peptide or protein features.

  19. Automated solid-phase peptide synthesis to obtain therapeutic peptides

    Directory of Open Access Journals (Sweden)

    Veronika Mäde

    2014-05-01

    Full Text Available The great versatility and the inherent high affinities of peptides for their respective targets have led to tremendous progress for therapeutic applications in the last years. In order to increase the drugability of these frequently unstable and rapidly cleared molecules, chemical modifications are of great interest. Automated solid-phase peptide synthesis (SPPS offers a suitable technology to produce chemically engineered peptides. This review concentrates on the application of SPPS by Fmoc/t-Bu protecting-group strategy, which is most commonly used. Critical issues and suggestions for the synthesis are covered. The development of automated methods from conventional to essentially improved microwave-assisted instruments is discussed. In order to improve pharmacokinetic properties of peptides, lipidation and PEGylation are described as covalent conjugation methods, which can be applied by a combination of automated and manual synthesis approaches. The synthesis and application of SPPS is described for neuropeptide Y receptor analogs as an example for bioactive hormones. The applied strategies represent innovative and potent methods for the development of novel peptide drug candidates that can be manufactured with optimized automated synthesis technologies.

  20. What peptides these deltorphins be.

    Science.gov (United States)

    Lazarus, L H; Bryant, S D; Cooper, P S; Salvadori, S

    1999-02-01

    The deltorphins are a class of highly selective delta-opioid heptapeptides from the skin of the Amazonian frogs Phyllomedusa sauvagei and P. bicolor. The first of these fascinating peptides came to light in 1987 by cloning of the cDNA of from frog skins, while the other members of this family were identified either by cDNA or isolation of the peptides. The distinctive feature of deltorphins is the presence of a naturally occurring D-enantiomer at the second position in their common N-terminal sequence, Tyr-D-Xaa-Phe, comparable to dermorphin, which is the prototype of a group of mu-selective opioids from the same source. The D-amino acid and the anionic residues, either Glu or Asp, as well as their unique amino acid compositions are responsible for the remarkable biostability, high delta-receptor affinity, bioactivity and peptide conformation. This review summarizes a decade of research from many laboratories that defined which residues and substituents in the deltorphins interact with the delta-receptor and characterized pharmacological and physiological activities in vitro and in vivo. It begins with a historical description of the topic and presents general schema for the synthesis of peptide analogues of deltorphins A, B and C as a means to document the methods employed in producing a myriad of analogues. Structure activity studies of the peptides and their pharmacological activities in vitro are detailed in abundantly tabulated data. A brief compendium of the current level of knowledge of the delta-receptor assists the reader to appreciate the rationale for the design of these analogues. Discussion of the conformation of these peptides addresses how structure leads to further hypotheses regarding ligand receptor interaction. The review ends with a broad discussion of the potential applications of these peptides in clinical and therapeutic settings.

  1. Structural Basis for Degenerate Recognition of Natural HIV Peptide Variants by Cytotoxic Lymphocytes

    International Nuclear Information System (INIS)

    Martinez-Hackert, E.; Anikeeva, N.; Kalams, S.; Walker, B.; Hendrickson, W.; Sykulev, Y.

    2006-01-01

    It is well established that even small changes in amino acid side chains of antigenic peptide bound to MHC protein may completely abrogate recognition of the peptide-MHC (pMHC) complex by the T-cell receptor (TCR). Often, however, several non-conservative substitutions in the peptide antigen are accommodated and do not impair its recognition by TCR. For example, a preponderance of natural sequence variants of the HIV p17 Gag-derived peptide SLYNTVATL (SL9) are recognized by cytotoxic T lymphocytes (CTL), which implies that interactions with SL9 variants are degenerate both with respect to the class I MHC molecule and with respect to TCR. Here we study the molecular basis for this degenerate recognition of SL9 variants. We show that several SL9 variants bind comparably well to soluble HLA-A2 and to a particular soluble TCR and that these variants are active in the cognate cytotoxicity assay. Natural SL9 variation is restricted by its context in the HIV p17 matrix protein, and we have used synthetic variants to explore the wider spectrum of recognition. High-resolution crystal structures of seven selected SL9 variants bound to HLA-A2 all have remarkably similar peptide conformations and side-chain dispositions outside sites of substitution. This preservation of the peptide conformation despite epitope variations suggests a mechanism for the observed degeneracy in pMHC recognition by TCR, and may contribute to the persistence of SL9-mediated immune responses in chronically infected individuals

  2. Novel tumor-targeting, self-assembling peptide nanofiber as a carrier for effective curcumin delivery

    Directory of Open Access Journals (Sweden)

    Liu J

    2013-12-01

    Full Text Available Jianfeng Liu, Jinjian Liu, Hongyan Xu, Yumin Zhang, Liping Chu, Qingfen Liu, Naling Song, Cuihong YangTianjin Key Laboratory of Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Science and Peking Union Medical College, People's Republic of ChinaAbstract: The poor aqueous solubility and low bioavailability of curcumin restrict its clinical application for cancer treatment. In this study, a novel tumor-targeting nanofiber carrier was developed to improve the solubility and tumor-targeting ability of curcumin using a self-assembled Nap-GFFYG-RGD peptide. The morphologies of the peptide nanofiber and the curcumin-encapsulated nanofiber were visualized by transmission electron microscopy. The tumor-targeting activity of the curcumin-encapsulated Nap-GFFYG-RGD peptide nanofiber (f-RGD-Cur was studied in vitro and in vivo, using Nap-GFFYG-RGE peptide nanofiber (f-RGE-Cur as the control. Curcumin was encapsulated into the peptide nanofiber, which had a diameter of approximately 10–20 nm. Curcumin showed sustained-release behavior from the nanofibers in vitro. f-RGD-Cur showed much higher cellular uptake in αvβ3 integrin-positive HepG2 liver carcinoma cells than did non-targeted f-RGE-Cur, thereby leading to significantly higher cytotoxicity. Ex vivo studies further demonstrated that curcumin could accumulate markedly in mouse tumors after administration of f-RGD-Cur via the tail vein. These results indicate that Nap-GFFYG-RGD peptide self-assembled nanofibers are a promising hydrophobic drug delivery system for targeted treatment of cancer.Keywords: nanofiber, tumor-targeting, self-assembling, curcumin, drug delivery

  3. Sequencing Cyclic Peptides by Multistage Mass Spectrometry

    Science.gov (United States)

    Mohimani, Hosein; Yang, Yu-Liang; Liu, Wei-Ting; Hsieh, Pei-Wen; Dorrestein, Pieter C.; Pevzner, Pavel A.

    2012-01-01

    Some of the most effective antibiotics (e.g., Vancomycin and Daptomycin) are cyclic peptides produced by non-ribosomal biosynthetic pathways. While hundreds of biomedically important cyclic peptides have been sequenced, the computational techniques for sequencing cyclic peptides are still in their infancy. Previous methods for sequencing peptide antibiotics and other cyclic peptides are based on Nuclear Magnetic Resonance spectroscopy, and require large amount (miligrams) of purified materials that, for most compounds, are not possible to obtain. Recently, development of mass spectrometry based methods has provided some hope for accurate sequencing of cyclic peptides using picograms of materials. In this paper we develop a method for sequencing of cyclic peptides by multistage mass spectrometry, and show its advantages over single stage mass spectrometry. The method is tested on known and new cyclic peptides from Bacillus brevis, Dianthus superbus and Streptomyces griseus, as well as a new family of cyclic peptides produced by marine bacteria. PMID:21751357

  4. Cyclic peptide therapeutics: past, present and future.

    Science.gov (United States)

    Zorzi, Alessandro; Deyle, Kaycie; Heinis, Christian

    2017-06-01

    Cyclic peptides combine several favorable properties such as good binding affinity, target selectivity and low toxicity that make them an attractive modality for the development of therapeutics. Over 40 cyclic peptide drugs are currently in clinical use and around one new cyclic peptide drug enters the market every year on average. The vast majority of clinically approved cyclic peptides are derived from natural products, such as antimicrobials or human peptide hormones. New powerful techniques based on rational design and in vitro evolution have enabled the de novo development of cyclic peptide ligands to targets for which nature does not offer solutions. A look at the cyclic peptides currently under clinical evaluation shows that several have been developed using such techniques. This new source for cyclic peptide ligands introduces a freshness to the field, and it is likely that de novo developed cyclic peptides will be in clinical use in the near future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. [New strategy for RNA vectorization in mammalian cells. Use of a peptide vector].

    Science.gov (United States)

    Vidal, P; Morris, M C; Chaloin, L; Heitz, F; Divita, G

    1997-04-01

    A major barrier for gene delivery is the low permeability of nucleic acids to cellular membranes. The development of antisenses and gene therapy has focused mainly on improving methods of oligonucleotide or gene delivery to the cell. In this report we described a new strategy for RNA cell delivery, based on a short single peptide. This peptide vector is derived from both the fusion domain of the gp41 protein of HIV and the nuclear localization sequence of the SV40 large T antigen. This peptide vector localizes rapidly to the cytoplasm then to the nucleus of human fibroblasts (HS-68) within a few minutes and exhibits a high affinity for a single-stranded mRNA encoding the p66 subunit of the HIV-1 reverse transcriptase (in a 100 nM range). The peptide/RNA complex formation involves mainly electrostatic interactions between the basic residues of the peptide and the charges on the phosphate group of the RNA. In the presence of the peptide-vector fluorescently-labelled mRNA is delivered into the cytoplasm of mammalian cells (HS68 human fibroblasts) in less than 1 h with a relatively high efficiency (80%). This new concept based on a peptide-derived vector offers several advantages compared to other compounds commonly used in gene delivery. This vector is highly soluble and exhibits no cytotoxicity at the concentrations used for optimal gene delivery. This result clearly supports the fact that this peptide vector is a powerful tool and that it can be used widely, as much for laboratory research as for new applications and development in gene and/or antisense therapy.

  6. Annexin 1 and Melanocortin Peptide Therapy for Protection Against Ischaemic-Reperfusion Damage in the Heart

    Directory of Open Access Journals (Sweden)

    F.N.E. Gavins

    2006-01-01

    Full Text Available Cardiovascular disease is a major cause of mortality within the western world affecting 2.7 million British people. This review highlights the beneficial effects of naturally occurring hormones and their peptides, in myocardial ischaemic-injury (MI models, a disease pathology in which cytokines and neutrophils play a causal role. Here we discuss two distinct classes of endogenous peptides: the steroid inducible annexin 1 and the melanocortin peptides. Annexin 1 and the melanocortins counteract the most important part of the host inflammatory response, namely, the process of leukocyte extravasation, as well as release of proinflammatory mediators. Their biological effects are mediated via the seven transmembrane G-protein-coupled receptors, the fMLP receptor family (or FPR, and the melanocortin receptors, respectively. Pharmacological analysis has demonstrated that the first 24 amino acids of the N-terminus (termed Ac2-26 are the most active region. Both exogenous annexin 1 and its peptides demonstrate cardioprotectiveness and continuing work is required to understand this annexin 1/FPR relationship fully. The melanocortin peptides are derived from a precursor molecule called the POMC protein. These peptides display potent anti-inflammatory effects in human and animal models of disease. In MI, the MC3R has been demonstrated to play an important role in mediating the protective effects of these peptides. The potential anti-inflammatory role for endogenous peptides in cardiac disease is in its infancy. The inhibition of cell migration and release of cytokines and other soluble mediators appears to play an important role in affording protection in ischaemic injury and thus may lead to potential therapeutic targets.

  7. Peptide Vaccine: Progress and Challenges

    Directory of Open Access Journals (Sweden)

    Weidang Li

    2014-07-01

    Full Text Available Conventional vaccine strategies have been highly efficacious for several decades in reducing mortality and morbidity due to infectious diseases. The bane of conventional vaccines, such as those that include whole organisms or large proteins, appear to be the inclusion of unnecessary antigenic load that, not only contributes little to the protective immune response, but complicates the situation by inducing allergenic and/or reactogenic responses. Peptide vaccines are an attractive alternative strategy that relies on usage of short peptide fragments to engineer the induction of highly targeted immune responses, consequently avoiding allergenic and/or reactogenic sequences. Conversely, peptide vaccines used in isolation are often weakly immunogenic and require particulate carriers for delivery and adjuvanting. In this article, we discuss the specific advantages and considerations in targeted induction of immune responses by peptide vaccines and progresses in the development of such vaccines against various diseases. Additionally, we also discuss the development of particulate carrier strategies and the inherent challenges with regard to safety when combining such technologies with peptide vaccines.

  8. Solubility study of Tc(IV) oxides

    International Nuclear Information System (INIS)

    Liu, D.J.; Fan, X.H.

    2005-01-01

    The deep geological disposal of the high level radioactive wastes is expected to be a safer disposal method in most countries. The long-lived fission product 99 Tc is present in large quantities in nuclear wastes and its chemical behavior in aqueous solution is of considerable interest. Under oxidizing conditions technetium exists as the anionic species TcO 4 - whereas under the reducing conditions, expected to exist in a deep geological repository, it is generally predicted that technetium will be present as TcO 2 ·nH 2 O. Hence, the mobility of Tc(IV) in reducing groundwater may be limited by the solubility of TcO 2 ·nH 2 O under these conditions. Due to this fact it is important to investigate the solubility of TcO 2 ·nH 2 O. The solubility determines the release of radionuclides from waste form and is used as a source term in radionuclide migration analysis in performance assessment of radioactive waste repository. Technetium oxide was prepared by reduction of a technetate solution with Sn 2 + . The solubility of Tc(IV) oxide has been determined in simulated groundwater and redistilled water under aerobic and anaerobic conditions. The effects of pH and CO 3 2- concentration of solution on solubility of Tc(IV) oxide were studied. The concentration of total technetium and Tc(IV) species in the solutions were periodically determined by separating the oxidized and reduced technetium species using a solvent extraction procedure and counting the beta activity of the 99 Tc with a liquid scintillation counter. The experimental results show that the rate of oxidation of Tc(IV) in simulated groundwater and redistilled water is about (1.49-1.86) x 10 -9 mol/(L·d) under aerobic conditions, but Tc(IV) in simulated groundwater and redistilled water is not oxidized under anaerobic conditions. Under aerobic or anaerobic conditions the solubility of Tc(IV) oxide in simulated groundwater and redistilled water is equal on the whole after centrifugation or ultrafiltration. The

  9. Double-Stranded Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2001-01-01

    A novel class of compounds, known as peptide nucleic acids, form double-stranded structures with one another and with ssDNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker.......A novel class of compounds, known as peptide nucleic acids, form double-stranded structures with one another and with ssDNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  10. Influence of milling process on efavirenz solubility

    Directory of Open Access Journals (Sweden)

    Erizal Zaini

    2017-01-01

    Full Text Available Introduction: The aim of this study was to investigate the influence of the milling process on the solubility of efavirenz. Materials and Methods: Milling process was done using Nanomilling for 30, 60, and 180 min. Intact and milled efavirenz were characterized by powder X-ray diffraction, scanning electron microscopy (SEM, spectroscopy infrared (IR, differential scanning calorimetry (DSC, and solubility test. Results: The X-ray diffractogram showed a decline on peak intensity of milled efavirenz compared to intact efavirenz. The SEM graph depicted the change from crystalline to amorphous habit after milling process. The IR spectrum showed there was no difference between intact and milled efavirenz. Thermal analysis which performed by DSC showed a reduction on endothermic peak after milling process which related to decreasing of crystallinity. Solubility test of intact and milled efavirenz was conducted in distilled water free CO2with 0.25% sodium lauryl sulfate media and measured using high-performance liquid chromatography method with acetonitrile: distilled water (80:20 as mobile phases. The solubility was significantly increased (P < 0.05 after milling processes, which the intact efavirenz was 27.12 ± 2.05, while the milled efavirenz for 30, 60, and 180 min were 75.53 ± 1.59, 82.34 ± 1.23, and 104.75 ± 0.96 μg/mL, respectively. Conclusions: Based on the results, the solubility of efavirenz improved after milling process.

  11. Solubility of lithium deuteride in liquid lithium

    International Nuclear Information System (INIS)

    Veleckis, E.; Yonco, R.M.; Maroni, V.A.

    1977-01-01

    The solubility of LiD in liquid lithium between the eutectic and monotectic temperatures was measured using a direct sampling method. Solubilities were found to range from 0.0154 mol.% LiD at 199 0 C to 3.32 mol.% LiD at 498 0 C. The data were used in the derivation of an expression for the activity coefficient of LiD as a function of temperature and composition and an equation relating deuteride solubility and temperature, thus defining the liquidus curve. Similar equations were also derived for the Li-LiH system using the existing solubility data. Extrapolation of the liquidus curves yielded the eutectic concentrations (0.040 mol.% LiH and 0.035 mol.% LiD) and the freezing point depressions (0.23 0 C for Li-LiH and 0.20 0 C for Li-LiD) at the eutectic point. The results are compared with the literature data for hydrogen and deuterium. The implications of the relatively high solubility of hydrogen isotopes in lithium just above the melting point are discussed with respect to the cold trapping of tritium in fusion reactor blankets. (Auth.)

  12. Solubility studies of Np(IV)

    International Nuclear Information System (INIS)

    Zhang Yingjie; Yao Jun; Jiao Haiyang; Ren Lihong; Zhou Duo; Fan Xianhua

    2001-01-01

    The solubility of Np(IV) in simulated underground water and redistilled water has been measured with the variations of pH(6-12) and storage time (0-100 d) in the presence of reductant (Na 2 S 2 O 4 , metallic Fe). All experiments are performed in a low oxygen concentration glove box containing high purity Ar(99.99%), with an oxygen content of less than 5 x 10 -6 mol/mol. Experimental results show that the variation of pH in solution has little effect on the solubility of Np(IV) in the two kinds of water; the measured solubility of Np(IV) is affected by the composition of solution; with Na 2 S 2 O 4 as a reductant, the solubility of Np(IV) in simulated underground water is (9.23 +- 0.48) x 10 -10 mol/L, and that in redistilled water is (8.31 +- 0.35) x 10 -10 mol/L; with metallic Fe as a reductant, the solubility of Np(IV) in simulated underground water is (1.85 +- 0.56) x 10 -9 mol/L, and that in redistilled water is (1.48 +- 0.66) x 10 -9 mol/L

  13. Solubility of pllutonium in alkaline salt solutions

    International Nuclear Information System (INIS)

    Hobbs, D.T.; Edwards, T.B.

    1993-01-01

    Plutonium solubility data from several studies have been evaluated. For each data set, a predictive model has been developed where appropriate. In addition, a statistical model and corresponding prediction intervals for plutonium solubility as a quadratic function of the hydroxide concentration have been developed. Because of the wide range of solution compositions, the solubility of plutonium can vary by as much as three orders of magnitude for any given hydroxide concentration and still remain within the prediction interval. Any nuclear safety assessments that depend on the maximum amount of plutonium dissolved in alkaline salt solutions should use concentrations at least as great as the upper prediction limits developed in this study. To increase the confidence in the prediction model, it is recommended that additional solubility tests be conducted at low hydroxide concentrations and with all of the other solution components involved. To validate the model for application to actual waste solutions, it is recommended that the plutonium solubilities in actual waste solutions be determined and compared to the values predicted by the quadratic model

  14. 40 CFR Table 7 to Subpart Vvvvvv... - Partially Soluble HAP

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 14 2010-07-01 2010-07-01 false Partially Soluble HAP 7 Table 7 to... Pt. 63, Subpt. VVVVVV, Table 7 Table 7 to Subpart VVVVVV of Part 63—Partially Soluble HAP As required... partially soluble HAP listed in the following table. Partially soluble HAP name CAS No. 1. 1,1,1...

  15. Interlaboratory validation of small-scale solubility and dissolution measurements of poorly water-soluble drugs

    DEFF Research Database (Denmark)

    Andersson, Sara B. E.; Alvebratt, Caroline; Bevernage, Jan

    2016-01-01

    The purpose of this study was to investigate the interlaboratory variability in determination of apparent solubility (Sapp) and intrinsic dissolution rate (IDR) using a miniaturized dissolution instrument. Three poorly water-soluble compounds were selected as reference compounds and measured at m...

  16. Effect of cyclodextrin complexation on the aqueous solubility and solubility/dose ratio of praziquantel.

    Science.gov (United States)

    Maragos, Stratos; Archontaki, Helen; Macheras, Panos; Valsami, Georgia

    2009-01-01

    Praziquantel (PZQ), the primary drug of choice in the treatment of schistosomiasis, is a highly lipophilic drug that possesses high permeability and low aqueous solubility and is, therefore, classified as a Class II drug according to the Biopharmaceutics Classification System (BCS). In this work, beta-cyclodextrin (beta-CD) and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) were used in order to determine whether increasing the aqueous solubility of a drug by complexation with CDs, a BCS-Class II compound like PZQ could behave as BCS-Class I (highly soluble/highly permeable) drug. Phase solubility and the kneading and lyophilization techniques were used for inclusion complex preparation; solubility was determined by UV spectroscopy. The ability of the water soluble polymer polyvinylpyrolidone (PVP) to increase the complexation and solubilization efficiency of beta-CD and HP-beta-CD for PZQ was examined. Results showed significant improvement of PZQ solubility in the presence of both cyclodextrins but no additional effect in the presence of PVP. The solubility/dose ratios values of PZQ-cyclodextrin complexes calculated considering the low (150 mg) and the high dose (600 mg) of PZQ, used in practice, indicate that PZQ complexation with CDs may result in drug dosage forms that would behave as a BCS-Class I depending on the administered dose.

  17. Effect of enzymatic treatment of extracted sunflower proteins on solubility, amino acid composition, and surface activity.

    Science.gov (United States)

    Conde, José Miñones; Escobar, María del Mar Yust; Pedroche Jiménez, Justo J; Rodríguez, Francisco Millán; Rodríguez Patino, Juan M

    2005-10-05

    Industrial proteins from agriculture of either animal or vegetable origin, including their peptide derivatives, are of great importance, from the qualitative and quantitative point of view, in food formulations (emulsions and foams). A fundamental understanding of the physical, chemical, and functional properties of these proteins is essential if the performance of proteins in foods is to be improved and if underutilized proteins, such as plant proteins (and their hydrolysates and peptides derivatives), are to be increasingly used in traditional and new processed food products (safe, high-quality, health foods with good nutritional value). In this contribution we have determined the main physicochemical characteristics (solubility, composition, and analysis of amino acids) of a sunflower protein isolate (SPI) and its hydrolysates with low (5.62%), medium (23.5%), and high (46.3%) degrees of hydrolysis. The hydrolysates were obtained by enzymatic treatment with Alcalase 2.4 L for DH 5.62 and 23.5% and with Alcalase 2.4 L and Flavorzyme 1000 MG sequentially for DH 46.3%. The protein concentration dependence on surface pressure (surface pressure isotherm), a measure of the surface activity of the products (SPI and its hydrolysates), was obtained by tensiometry. We have observed that the degree of hydrolysis has an effect on solubility, composition, and content of the amino acids of the SPI and its hydrolysates. The superficial activity and the adsorption efficiency were also affected by the degree of hydrolysis.

  18. Structural Characterization of Peptide Antibodies

    DEFF Research Database (Denmark)

    Chailyan, Anna; Marcatili, Paolo

    2015-01-01

    The role of proteins as very effective immunogens for the generation of antibodies is indisputable. Nevertheless, cases in which protein usage for antibody production is not feasible or convenient compelled the creation of a powerful alternative consisting of synthetic peptides. Synthetic peptides...... can be modified to obtain desired properties or conformation, tagged for purification, isotopically labeled for protein quantitation or conjugated to immunogens for antibody production. The antibodies that bind to these peptides represent an invaluable tool for biological research and discovery....... To better understand the underlying mechanisms of antibody-antigen interaction here we present a pipeline developed by us to structurally classify immunoglobulin antigen binding sites and to infer key sequence residues and other variables that have a prominent role in each structural class....

  19. Self-assembling peptide semiconductors

    Science.gov (United States)

    Tao, Kai; Makam, Pandeeswar; Aizen, Ruth; Gazit, Ehud

    2017-01-01

    Semiconductors are central to the modern electronics and optics industries. Conventional semiconductive materials bear inherent limitations, especially in emerging fields such as interfacing with biological systems and bottom-up fabrication. A promising candidate for bioinspired and durable nanoscale semiconductors is the family of self-assembled nanostructures comprising short peptides. The highly ordered and directional intermolecular π-π interactions and hydrogen-bonding network allow the formation of quantum confined structures within the peptide self-assemblies, thus decreasing the band gaps of the superstructures into semiconductor regions. As a result of the diverse architectures and ease of modification of peptide self-assemblies, their semiconductivity can be readily tuned, doped, and functionalized. Therefore, this family of electroactive supramolecular materials may bridge the gap between the inorganic semiconductor world and biological systems. PMID:29146781

  20. Antimicrobial Peptide Production and Purification.

    Science.gov (United States)

    Suda, Srinivas; Field, Des; Barron, Niall

    2017-01-01

    Antimicrobial peptides (AMPs) are natural defense compounds which are synthesized as ribosomal gene-encoded pre-peptides and produced by all living organisms. AMPs are small peptides, usually cationic and typically have hydrophobic residues which interact with cell membranes and have either a narrow or broad spectrum of biological activity. AMPs are isolated from the natural host or heterologously expressed in other hosts such as Escherichia coli. The proto-typical lantibiotic Nisin is a widely used AMP that is produced by the food-grade organism Lactococcus lactis. Although AMP production and purification procedures require optimization for individual AMPs, the Nisin production and purification protocol outlined in this chapter can be easily applied with minor modifications for the production and purification of other lantibiotics or AMPs. While Nisin is produced and secreted into the supernatant, steps to recover Nisin from both cell-free supernatant and cell pellet are outlined in detail.

  1. Delivery systems for antimicrobial peptides

    DEFF Research Database (Denmark)

    Nordström, Randi; Malmsten, Martin

    2017-01-01

    Due to rapidly increasing resistance development against conventional antibiotics, finding novel approaches for the treatment of infections has emerged as a key health issue. Antimicrobial peptides (AMPs) have attracted interest in this context, and there is by now a considerable literature...... on the identification such peptides, as well as on their optimization to reach potent antimicrobial and anti-inflammatory effects at simultaneously low toxicity against human cells. In comparison, delivery systems for antimicrobial peptides have attracted considerably less interest. However, such delivery systems...... are likely to play a key role in the development of potent and safe AMP-based therapeutics, e.g., through reducing chemical or biological degradation of AMPs either in the formulation or after administration, by reducing adverse side-effects, by controlling AMP release rate, by promoting biofilm penetration...

  2. Radioactive labelling of peptidic hormones

    International Nuclear Information System (INIS)

    Fromageot, P.; Pradelles, P.; Morgat, J.L.; Levine, H.

    1976-01-01

    The labelling of peptidic hormones requires stability, specificity and sensitivity of the label. Introduction of a radioactive atome is one way to satisfy these criteria. Several processes have been described to prepare radioactive TRF: synthesis of the peptide with labelled aminoacids or introduction of the label into the hormone. In that approach, tritium can be substituted in the imidazole ring, via precursors activating the proper carbon. Monoiodo TRF leads essentially to tritium labelling of the 5 positions whereas monoazo TRF allows the preparation of 3 H TRF labelled in the 2 positions. Di-substituted TRF leads to labelling into the 2 and 5 carbons. Labelled analogs of TRF can be prepared with labelled iodine; further developments of peptide labelling, will be presented. In particular, the homolytic scission of the C-iodine, bond by photochemical activation. The nascent carbon radical can be stabilized by a tritiated scavenger. This approach eliminates the use of heavy metal catalysts

  3. The Pig PeptideAtlas

    DEFF Research Database (Denmark)

    Hesselager, Marianne Overgaard; Codrea, Marius; Sun, Zhi

    2016-01-01

    Biological research of Sus scrofa, the domestic pig, is of immediate relevance for food production sciences, and for developing pig as a model organism for human biomedical research. Publicly available data repositories play a fundamental role for all biological sciences, and protein data...... repositories are in particular essential for the successful development of new proteomic methods. Cumulative proteome data repositories, including the PeptideAtlas, provide the means for targeted proteomics, system-wide observations, and cross-species observational studies, but pigs have so far been...... underrepresented in existing repositories. We here present a significantly improved build of the Pig PeptideAtlas, which includes pig proteome data from 25 tissues and three body fluid types mapped to 7139 canonical proteins. The content of the Pig PeptideAtlas reflects actively ongoing research within...

  4. Mass spectrometric differentiation of linear peptides composed of L-amino acids from isomers containing one D-amino acid residue.

    Science.gov (United States)

    Serafin, Scott V; Maranan, Rhonda; Zhang, Kangling; Morton, Thomas Hellman

    2005-09-01

    MS/MS of electrosprayed ions is shown to have the capacity to discriminate between peptides that differ by configuration about their alpha-carbons. It is not necessary for the peptides to possess tertiary structures that are affected by stereochemistry, since five epimers of the pentapeptide, H2N-Gly-Leu-Ser-Phe-Ala-OH (GLSFA) all display different collisionally activated dissociation (CAD) patterns of their protonated parent ions. The figure of merit, r, is a ratio of ratios of fragment ion abundances between stereoisomers, where r = 1 corresponds to no stereochemical effect. Values of r as high as 3.8 are seen for diastereomer pairs. Stereochemical effects are also seen for the diprotonated dodecapeptide H2N-Leu-Val-Phe-Phe-Ala-Glu-Asp-Val-Gly-Ser-Asn-Lys-OH (LVFFAEDVGSNK), a tryptic fragment from the amyloid beta-protein. Triply charged complexes of the protonated dodecapeptide with cobalt(II) ions undergo CAD at lower collision energies than do doubly protonated LVFFAEDVGSNK ions. Statistically significant (p < 0.01) differences between the all-L-dodecapeptide and the ones containing a d-serine or a D-aspartic acid are observed.

  5. A novel Alaska pollack-derived peptide, which increases glucose uptake in skeletal muscle cells, lowers the blood glucose level in diabetic mice.

    Science.gov (United States)

    Ayabe, Tatsuhiro; Mizushige, Takafumi; Ota, Wakana; Kawabata, Fuminori; Hayamizu, Kohsuke; Han, Li; Tsuji, Tomoko; Kanamoto, Ryuhei; Ohinata, Kousaku

    2015-08-01

    We found that the tryptic digest of Alaska pollack protein exhibits a glucose-lowering effect in KK-Ay mice, a type II diabetic model. We then searched for glucose-lowering peptides in the digest. Ala-Asn-Gly-Glu-Val-Ala-Gln-Trp-Arg (ANGEVAQWR) was identified from a peak of the HPLC fraction selected based on the glucose-lowering activity in an insulin resistance test using ddY mice. ANGEVAQWR (3 mg kg(-1)) decreased the blood glucose level after intraperitoneal administration. Among its fragment peptides, the C-terminal tripeptide, Gln-Trp-Arg (QWR, 1 mg kg(-1)), lowered the blood glucose level, suggesting that the C-terminal is critical for glucose-lowering activity. QWR also enhanced glucose uptake into C2C12, a mouse skeletal muscle cell line. QWR did not induce the phosphorylation of serine/threonine protein kinase B (Akt) and adenosine monophosphate-activated protein kinase (AMPK). We also demonstrated that QWR lowered the blood glucose level in NSY and KK-Ay, type II diabetic models.

  6. Solubilities of boric acid in heavy water

    International Nuclear Information System (INIS)

    Nakai, Shigetsugu; Aoi, Hideki; Hayashi, Ken-ichi; Katoh, Taizo; Watanabe, Takashi.

    1988-01-01

    A gravimetric analysis using meta-boric acid (HBO 2 or DBO 2 ) as a weighing form has been developed for solubility measurement. The method gave satisfactory results in preliminary measurement of solubilities of boric acid in light water. By using this method, the solubilities of 10 B enriched D 3 BO 3 in heavy water were measured. The results are as follows; 2.67 (7deg C), 3.52 (15deg C), 5.70 (30deg C), 8.87 (50deg C) and 12.92 (70deg C) w/o, respectively. These values are about 10% lower than those in light water. Thermodynamical consideration based on the data shows that boric acid is the water structure breaker. (author)

  7. Resveratrol cocrystals with enhanced solubility and tabletability.

    Science.gov (United States)

    Zhou, Zhengzheng; Li, Wanying; Sun, Wei-Jhe; Lu, Tongbu; Tong, Henry H Y; Sun, Changquan Calvin; Zheng, Ying

    2016-07-25

    Two new 1:1 cocrystals of resveratrol (RES) with 4-aminobenzamide (RES-4ABZ) and isoniazid (RES-ISN) were synthesized by liquid assisted grinding (LAG) and rapid solvent removal (RSR) methods using ethanol as solvent. Their physiochemical properties were characterized using PXRD, DSC, solid state and solution NMR, FT-IR, and HPLC. Pharmaceutically relevant properties, including tabletability, solubility, intrinsic dissolution rate, and hygroscopicity, were evaluated. Temperature-composition phase diagram for RES-ISN cocrystal system was constructed from DSC data. Both cocrystals show higher solubility than resveratrol over a broad range of pH. They are phase stable and non-hygroscopic even under high humidity conditions. Importantly, both cocrystals exhibit improved solubility and tabletability compared with RES, which make them more suitable candidates for tablet formulation development. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. AW-101 entrained solids - Solubility versus temperature

    International Nuclear Information System (INIS)

    GJ Lumetta; RC Lettau; GF Piepel

    2000-01-01

    This report describes the results of a test conducted by Battelle to assess the solubility of the solids entrained in the diluted AW-101 low-activity waste (LAW) sample. BNFL requested Battelle to dilute the AW-1-1 sample using de-ionized water to mimic expected plant operating conditions. BNFL further requested Battelle to assess the solubility of the solids present in the diluted AW-101 sample versus temperature conditions of 30, 40, and 50 C. BNFL requested these tests to assess the composition of the LAW supernatant and solids versus expected plant-operating conditions. The work was conducted according to test plan BNFL-TP-29953-7, Rev. 0, Determination of the Solubility of LAW Entrained Solids. The test went according to plan, with no deviations from the test plan

  9. Solubility and stability of inorganic carbonates

    International Nuclear Information System (INIS)

    Taylor, P.

    1987-01-01

    The chemistry of inorganic carbonates is reviewed, with emphasis on solubility and hydrolytic stability, in order to identify candidate waste forms for immobilization and disposal of 14 C. At present, CaCO 3 and BaCO 3 are the two most widely favoured wasted forms, primarily because they are the products of proven CO 2 -scrubbing technology. However, they have relatively high solubilities in non-alkaline solutions, necessitating care in selecting and assessing an appropriate disposal environment. Three compounds with better solubility characteristics in near-neutral waters are identified: bismutite, (BiO) 2 CO 3 ; hydrocerussite, Pb 3 (OH) 2 (CO 3 ) 2 ; and rhodochrosite, MnCO 3 . Some of the limitations of each of these alternative waste forms are discussed

  10. A framework for API solubility modelling

    DEFF Research Database (Denmark)

    Conte, Elisa; Gani, Rafiqul; Crafts, Peter

    . In addition, most of the models are not predictive and requires experimental data for the calculation of the needed parameters. This work aims at developing an efficient framework for the solubility modelling of Active Pharmaceutical Ingredients (API) in water and organic solvents. With this framework......-SAFT) are used for solubility calculations when the needed interaction parameters or experimental data are available. The CI-UNIFAC is instead used when the previous models lack interaction parameters or when solubility data are not available. A new GC+ model for APIs solvent selection based...... on the hydrophobicity, hydrophilicity and polarity information of the API and solvent is also developed, for performing fast solvent selection and screening. Eventually, all the previous developments are integrated in a framework for their efficient and integrated use. Two case studies are presented: the first...

  11. Solubility of iron in liquid lead

    International Nuclear Information System (INIS)

    Ali-Khan, I.

    1981-01-01

    The use of liquid lead in high temperature chemical and metallurgical processes is well known. The structural materials applied for the containment of these processes are either iron base alloys or possess iron as an alloying element. Besides that, lead itself is alloyed in some steels to achieve some very useful properties. For understanding the effect of liquid lead in such structural materials, it is important to determine the solubility of iron in liquid lead which would also be indicative of the stability of these alloys. At the institute of reactor materials of KFA Juelich, investigations have been conducted to determine the solubility of iron in liquid lead up to a temperature of about 1000 0 C. In this presentation the data concerning the solubility of iron in liquid lead are brought up to date and discussed including the results of our previous investigations. (orig.)

  12. Equilibrium Solubility of CO2 in Alkanolamines

    DEFF Research Database (Denmark)

    Waseem Arshad, Muhammad; Fosbøl, Philip Loldrup; von Solms, Nicolas

    2014-01-01

    Equilibrium solubility of CO2 were measured in aqueous solutions of Monoethanolamine (MEA) and N,N-diethylethanolamine(DEEA). Equilibrium cells are generally used for these measurements. In this study, the equilibrium data were measured from the calorimetry. For this purpose a reaction calorimeter...... (model CPA 122 from ChemiSens AB, Sweden) was used. The advantage of this method is being the measurement of both heats of absorption and equilibrium solubility data of CO2 at the same time. The measurements were performed for 30 mass % MEA and 5M DEEA solutions as a function of CO2 loading at three...... different temperatures 40, 80 and 120 ºC. The measured 30 mass % MEA and 5M DEEA data were compared with the literature data obtained from different equilibrium cells which validated the use of calorimeters for equilibrium solubility measurements....

  13. Novel Formulations for Antimicrobial Peptides

    Directory of Open Access Journals (Sweden)

    Ana Maria Carmona-Ribeiro

    2014-10-01

    Full Text Available Peptides in general hold much promise as a major ingredient in novel supramolecular assemblies. They may become essential in vaccine design, antimicrobial chemotherapy, cancer immunotherapy, food preservation, organs transplants, design of novel materials for dentistry, formulations against diabetes and other important strategical applications. This review discusses how novel formulations may improve the therapeutic index of antimicrobial peptides by protecting their activity and improving their bioavailability. The diversity of novel formulations using lipids, liposomes, nanoparticles, polymers, micelles, etc., within the limits of nanotechnology may also provide novel applications going beyond antimicrobial chemotherapy.

  14. Peptides and the new endocrinology

    Science.gov (United States)

    Schwyzer, Robert

    1982-01-01

    The discovery of regulatory peptides common to the nervous and the endocrine systems (brain, gut, and skin) has brought about a revolution in our concepts of endocrinology and neurology. We are beginning to understand some of the complex interrelationships between soma and psyche that might, someday, be important for an integrated treatment of diseases. Examples of the actions of certain peptides in the periphery and in the central nervous system are given, and their biosynthesis and molecular anatomy as carriers for information are discussed.

  15. Novel Formulations for Antimicrobial Peptides

    Science.gov (United States)

    Carmona-Ribeiro, Ana Maria; Carrasco, Letícia Dias de Melo

    2014-01-01

    Peptides in general hold much promise as a major ingredient in novel supramolecular assemblies. They may become essential in vaccine design, antimicrobial chemotherapy, cancer immunotherapy, food preservation, organs transplants, design of novel materials for dentistry, formulations against diabetes and other important strategical applications. This review discusses how novel formulations may improve the therapeutic index of antimicrobial peptides by protecting their activity and improving their bioavailability. The diversity of novel formulations using lipids, liposomes, nanoparticles, polymers, micelles, etc., within the limits of nanotechnology may also provide novel applications going beyond antimicrobial chemotherapy. PMID:25302615

  16. Respiratory carcinogenicity assessment of soluble nickel compounds.

    Science.gov (United States)

    Oller, Adriana R

    2002-10-01

    The many chemical forms of nickel differ in physicochemical properties and biological effects. Health assessments for each main category of nickel species are needed. The carcinogenicity assessment of water-soluble nickel compounds has proven particularly difficult. Epidemiologic evidence indicates an association between inhalation exposures to nickel refinery dust containing soluble nickel compounds and increased risk of respiratory cancers. However, the nature of this association is unclear because of limitations of the exposure data, inconsistent results across cohorts, and the presence of mixed exposures to water-insoluble nickel compounds and other confounders that are known or suspected carcinogens. Moreover, well-conducted animal inhalation studies, where exposures were solely to soluble nickel, failed to demonstrate a carcinogenic potential. Similar negative results were seen in animal oral studies. A model exists that relates respiratory carcinogenic potential to the bioavailability of nickel ion at nuclear sites within respiratory target cells. This model helps reconcile human, animal, and mechanistic data for soluble nickel compounds. For inhalation exposures, the predicted lack of bioavailability of nickel ion at target sites suggests that water-soluble nickel compounds, by themselves, will not be complete human carcinogens. However, if inhaled at concentrations high enough to induce chronic lung inflammation, these compounds may enhance carcinogenic risks associated with inhalation exposure to other substances. Overall, the weight of evidence indicates that inhalation exposure to soluble nickel alone will not cause cancer; moreover, if exposures are kept below levels that cause chronic respiratory toxicity, any possible tumor-enhancing effects (particularly in smokers) would be avoided.

  17. SITE-94. Radionuclide solubilities for SITE-94

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, R.; Apted, M. [QuantiSci, Denver, CO (United States)

    1996-12-01

    In this report, solubility constraints are evaluated on radioelement source-term concentrations supporting the SITE-94 performance assessment. Solubility models are based on heterogeneous-equilibrium, mass- and charge-balance constraints incorporated into the EQ3/6 geochemical software package, which is used to calculate the aqueous speciation behavior and solubilities of U, Th, Pu, Np, Am, Ni, Ra, Se, Sn, Sr, Tc and Zr in site groundwaters and near-field solutions. The chemical evolution of the near field is approximated using EQ3/6 in terms of limiting conditions at equilibrium, or steady state, in three closed systems representing fully saturated bentonite, Fe{sup o} corrosion products of the canister, and spent fuel. The calculations consider both low-temperature (15 deg C) and high-temperature (80 deg C) conditions in the near field, and the existence of either reducing or strongly oxidizing conditions in each of the bentonite, canister, and spent-fuel barriers. Heterogeneities in site characteristics are evaluated through consideration of a range of initial groundwaters and their interactions with engineered barriers. Aqueous speciation models for many radioelements are constrained by thermodynamic data that are estimated with varying degrees of accuracy. An important question, however, is how accurate do these models need to be for purposes of estimating source-term concentrations? For example, it is unrealistic to expect a high degree of accuracy in speciation models if such models predict solubilities that are below the analytical detection limit for a given radioelement. From a practical standpoint, such models are irrelevant if calculated solubilities cannot be tested by direct comparison to experimental data. In the absence of models that are both accurate and relevant for conditions of interest, the detection limit could define a pragmatic upper limit on radioelement solubility 56 refs, 25 tabs, 10 figs

  18. SITE-94. Radionuclide solubilities for SITE-94

    International Nuclear Information System (INIS)

    Arthur, R.; Apted, M.

    1996-12-01

    In this report, solubility constraints are evaluated on radioelement source-term concentrations supporting the SITE-94 performance assessment. Solubility models are based on heterogeneous-equilibrium, mass- and charge-balance constraints incorporated into the EQ3/6 geochemical software package, which is used to calculate the aqueous speciation behavior and solubilities of U, Th, Pu, Np, Am, Ni, Ra, Se, Sn, Sr, Tc and Zr in site groundwaters and near-field solutions. The chemical evolution of the near field is approximated using EQ3/6 in terms of limiting conditions at equilibrium, or steady state, in three closed systems representing fully saturated bentonite, Fe o corrosion products of the canister, and spent fuel. The calculations consider both low-temperature (15 deg C) and high-temperature (80 deg C) conditions in the near field, and the existence of either reducing or strongly oxidizing conditions in each of the bentonite, canister, and spent-fuel barriers. Heterogeneities in site characteristics are evaluated through consideration of a range of initial groundwaters and their interactions with engineered barriers. Aqueous speciation models for many radioelements are constrained by thermodynamic data that are estimated with varying degrees of accuracy. An important question, however, is how accurate do these models need to be for purposes of estimating source-term concentrations? For example, it is unrealistic to expect a high degree of accuracy in speciation models if such models predict solubilities that are below the analytical detection limit for a given radioelement. From a practical standpoint, such models are irrelevant if calculated solubilities cannot be tested by direct comparison to experimental data. In the absence of models that are both accurate and relevant for conditions of interest, the detection limit could define a pragmatic upper limit on radioelement solubility

  19. Hydrogen solubility in austenite of Fe-Ni-Cr alloys

    International Nuclear Information System (INIS)

    Zhirnova, V.V.; Mogutnov, B.M.; Tomilin, I.A.

    1981-01-01

    Hydrogen solubility in Fe-Ni-Cr alloys at 600-1000 deg C is determined. Hydrogen solubility in ternary alloys can not be predicted on the basis of the data on its solubility in binary Fe-Ni, Fe-Cr alloys. Chromium and nickel effect on hydrogen solubility in iron is insignificant in comparison with the effect of these elements on carbon or nitrogen solubility [ru

  20. Dendroaspis natriuretic peptide binds to the natriuretic peptide clearance receptor

    International Nuclear Information System (INIS)

    Johns, Douglas G.; Ao, Zhaohui; Heidrich, Bradley J.; Hunsberger, Gerald E.; Graham, Taylor; Payne, Lisa; Elshourbagy, Nabil; Lu, Quinn; Aiyar, Nambi; Douglas, Stephen A.

    2007-01-01

    Dendroaspis natriuretic peptide (DNP) is a newly-described natriuretic peptide which lowers blood pressure via vasodilation. The natriuretic peptide clearance receptor (NPR-C) removes natriuretic peptides from the circulation, but whether DNP interacts with human NPR-C directly is unknown. The purpose of this study was to test the hypothesis that DNP binds to NPR-C. ANP, BNP, CNP, and the NPR-C ligands AP-811 and cANP(4-23) displaced [ 125 I]-ANP from NPR-C with pM-to-nM K i values. DNP displaced [ 125 I]-ANP from NPR-C with nM potency, which represents the first direct demonstration of binding of DNP to human NPR-C. DNP showed high pM affinity for the GC-A receptor and no affinity for GC-B (K i > 1000 nM). DNP was nearly 10-fold more potent than ANP at stimulating cGMP production in GC-A expressing cells. Blockade of NPR-C might represent a novel therapeutic approach in augmenting the known beneficial actions of DNP in cardiovascular diseases such as hypertension and heart failure

  1. Hydrogen terminal solubility in Zircaloy-4

    International Nuclear Information System (INIS)

    Vizcaino, Pablo; Banchik, Abrahan D.

    1999-01-01

    Terminal solubility temperature of hydrogen in zirconium and its alloys is an important parameter because hydrides precipitation embrittled these materials making them susceptible to the phenomenon known as retarded hydrogen cracking. This work continues the study presented in the 25 AATN Meeting. Within this framework, a study focused on determining these curves in recrystallized Zircaloy-4, using scanning differential calorimetric technique. Terminal solubility curves for Zircaloy-4 were constructed within a concentration range from 40 to 640 ppm in hydrogen weight and comparisons with results obtained by other authors were made. (author)

  2. Nitrogen solubility in nickel base multicomponent melts

    International Nuclear Information System (INIS)

    Bol'shov, L.A.; Stomakhin, A.Ya.; Sokolov, V.M.; Teterin, V.G.

    1984-01-01

    Applicability of various methods for calculation of nitrogen solubility in high-alloyed nickel base alloys, containing Cr, Fe, W, Mo, Ti, Nb, has been estimated. A possibility is shown to use the formUla, derived for the calculation of nitrogen solubility in iron on the basis of statistical theory for a grid model of solution which does not require limitations for the content of a solvent component. The calculation method has been used for nickel alloys, with the concentration of solvent, iron, being accepted equal to zero, and employing parameters of nitrogen interaction as determined for iron-base alloys

  3. Effect of amides on lithium tetraborate solubility

    Energy Technology Data Exchange (ETDEWEB)

    Tsekhanskij, R S; Skvortsov, V C; Molodkin, A K; Sadetdi-pov, Sh V [Chuvashskij Gosudarstvennyj Pedagogicheskij Inst., Cheboksary (USSR); Universitet Druzhby Narodov, Moscow (USSR))

    1983-03-01

    Using the methods of solubility, densi- and refractometry at 25 deg C, it has been established that the systems lithium tetraborate-formamide (acetamide, dimethyl-formamide)-water are of a simple eutonic type. Amides decrease the salt solubility. Lyotropic effect, as calculated for molar concentrations (-Lsub(M)) relative to the absolute value, increases from formamide to dimethyl-formamide. The sequence is determined by the fact that, when there is one or two hydrophilic methyl groups in amide molecules which are in contact with tetraborate, they decrease the hydration energy of lithium cations.

  4. Effect of amides on sodium tetraborate solubility

    International Nuclear Information System (INIS)

    Tsekhanskij, R.S.; Skvortsov, V.G.; Molodkin, A.K.; Sadetdinov, Sh.V.

    1986-01-01

    Methods of solubility and refractometry at 25 deg C were applied to investigate sodium tetraborate - formamide (dimethylformamide) - water systems. It is stated that they are of simple eutonic type as well as the earlier described sodium tetraborate-acetamide-water system. Amides reduce solubility of the salt. The effect of contact interaction between dissolved substances on salt cation hydration and thus on the value of liotropic amide effect is confirmed. This value is found to be also depend on the number of molecules of coordination water in the initial crystalline hydrate

  5. Effect of amides on lithium tetraborate solubility

    International Nuclear Information System (INIS)

    Tsekhanskij, R.S.; Skvortsov, V.C.; Molodkin, A.K.; Sadetdi- pov, Sh.V.

    1983-01-01

    Using the methods of solubility, densi- and refractometry at 25 deg C, it has been established that the systemS lithium tetraborate-formamide (acetamide, dimethyl-formamide)-water are of a simple eutonic type. Amides decrease the salt solubility. Lyotropic effect, as calculated for molar concentrations (-Lsub(M)) relative to the absolute value, increases from formamide to dimethylformamide. The sequence is determined by the fact that, when there is one or two hydrophilic methyl groups in amide molecules which are in contact with tetraborate, they decrease the hydration energy of lithium cations

  6. Effect of amides on sodium tetraborate solubility

    Energy Technology Data Exchange (ETDEWEB)

    Tsekhanskij, R S; Skvortsov, V G; Molodkin, A K; Sadetdinov, Sh V

    1986-11-01

    Methods of solubility and refractometry at 25 deg C were applied to investigate sodium tetraborate - formamide (dimethylformamide) - water systems. It is stated that they are of simple eutonic type as well as the earlier described sodium tetraborate-acetamide-water system. Amides reduce solubility of the salt. The effect of contact interaction between dissolved substances on salt cation hydration and thus on the value of liotropic amide effect is confirmed. This value is found to be also depend on the number of molecules of coordination water in the initial crystalline hydrate.

  7. Modeling of Salt Solubilities in Mixed Solvents

    DEFF Research Database (Denmark)

    Chiavone-Filho, O.; Rasmussen, Peter

    2000-01-01

    A method to correlate and predict salt solubilities in mixed solvents using a UNIQUAC+Debye-Huckel model is developed. The UNIQUAC equation is applied in a form with temperature-dependent parameters. The Debye-Huckel model is extended to mixed solvents by properly evaluating the dielectric...... constants and the liquid densities of the solvent media. To normalize the activity coefficients, the symmetric convention is adopted. Thermochemical properties of the salt are used to estimate the solubility product. It is shown that the proposed procedure can describe with good accuracy a series of salt...

  8. Toxins and antimicrobial peptides: interactions with membranes

    Science.gov (United States)

    Schlamadinger, Diana E.; Gable, Jonathan E.; Kim, Judy E.

    2009-08-01

    The innate immunity to pathogenic invasion of organisms in the plant and animal kingdoms relies upon cationic antimicrobial peptides (AMPs) as the first line of defense. In addition to these natural peptide antibiotics, similar cationic peptides, such as the bee venom toxin melittin, act as nonspecific toxins. Molecular details of AMP and peptide toxin action are not known, but the universal function of these peptides to disrupt cell membranes of pathogenic bacteria (AMPs) or a diverse set of eukaryotes and prokaryotes (melittin) is widely accepted. Here, we have utilized spectroscopic techniques to elucidate peptide-membrane interactions of alpha-helical human and mouse AMPs of the cathelicidin family as well as the peptide toxin melittin. The activity of these natural peptides and their engineered analogs was studied on eukaryotic and prokaryotic membrane mimics consisting of resistant pathogens.

  9. Histidine-Containing Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2000-01-01

    Peptide nucleic acids containing histidine moieties are provided. These compounds have applications including diagnostics, research and potential therapeutics.......Peptide nucleic acids containing histidine moieties are provided. These compounds have applications including diagnostics, research and potential therapeutics....

  10. Streptavidin-binding peptides and uses thereof

    Science.gov (United States)

    Szostak, Jack W. (Inventor); Wilson, David S. (Inventor); Keefe, Anthony D. (Inventor)

    2006-01-01

    The invention provides peptides with high affinity for streptavidin. These peptides may be expressed as part of fusion proteins to facilitate the detection, quantitation, and purification of proteins of interest.

  11. Biomedical Applications of Self-Assembling Peptides

    NARCIS (Netherlands)

    Radmalekshahi, Mazda; Lempsink, Ludwijn; Amidi, Maryam; Hennink, Wim E.; Mastrobattista, Enrico

    2016-01-01

    Self-assembling peptides have gained increasing attention as versatile molecules to generate diverse supramolecular structures with tunable functionality. Because of the possibility to integrate a wide range of functional domains into self-assembling peptides including cell attachment sequences,

  12. Computer-Aided Design of Antimicrobial Peptides

    DEFF Research Database (Denmark)

    Fjell, Christopher D.; Hancock, Robert E.W.; Jenssen, Håvard

    2010-01-01

    in antimicrobial activity. Consequently, the majority of peptides put into clinical trials have failed at some point, underlining the importance of a thorough peptide optimization. An important tool in peptide design and optimization is quantitative structure-activity relationship (QSAR) analysis, correlating...... chemical parameters with biological activities of the peptide, using statistical methods. In this review we will discuss two different in silico strategies of computer-aided antibacterial peptide design, a linear correlation model build as an extension of traditional principal component analysis (PCA......) and a non-linear artificial neural network model. Studies on structurally diverse peptides, have concluded that the PCA derived model are able to guide the antibacterial peptide design in a meaningful way, however requiring rather a high homology between the peptides in the test-set and the in silico...

  13. Novel production method of innovative antiangiogenic and antitumor small peptides in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Setrerrahmane S

    2017-11-01

    Full Text Available Sarra Setrerrahmane,1 Jian Yu,1 Jingchao Hao,1,2 Heng Zheng,3 Hanmei Xu1,3 1The Engineering Research Center of Peptide Drug Discovery and Development, China Pharmaceutical University, Nanjing, Jiangsu, 2College of Pharmacy & the Provincial Key Laboratory of Natural Drug and Pharmacology, Kunming, Yunnan, 3State Key Laboratory of Natural Medicines, Ministry of Education, China Pharmaceutical University, Nanjing, Jiangsu, People’s Republic of China Background: Developing innovative drugs with potent efficacy, specificity, and high safety remains an ongoing task in antitumor therapy development. In the last few years, peptide drugs have become attractive agents in cancer therapy. HM-3, mainly with antiangiogenic effect, and AP25, with an additional antiproliferative effect, are two peptides designed in our laboratory targeting αvβ3 and α5β1 integrins, respectively. The low molecular weight of the two peptides renders their recombinant expression very difficult, and the complicated structure of AP25 makes its chemical synthesis restricted, which presents a big challenge for its development.Methods: Bifunctional peptides designed by the ligation of HM-3 and AP25, using linkers with different flexibility, were prepared using recombinant DNA technology in Escherichia coli. The fusion peptides were expressed in a modified auto-induction medium based on a mixture of glucose, glycerol, and lactose as carbon substrates and NH4+ as nitrogen source without any amino acid or other elements. Subsequently, the antiangiogenic, antiproliferative, and cell adhesion assays were conducted to evaluate the bioactivity of the two fusion peptides.Results: The peptides were successfully expressed in a soluble form without any induction, which allows the culture to reach higher cell density before protein expression occurs. Human umbilical vein endothelial cell migration assay and chick embryo chorioallantoic membrane assay showed, at low doses, a significantly

  14. Characterization of cyclic peptides containing disulfide bonds

    OpenAIRE

    Johnson, Mindy; Liu, Mingtao; Struble, Elaine; Hettiarachchi, Kanthi

    2015-01-01

    Unlike linear peptides, analysis of cyclic peptides containing disulfide bonds is not straightforward and demands indirect methods to achieve a rigorous proof of structure. Three peptides that belong to this category, p-Cl-Phe-DPDPE, DPDPE, and CTOP, were analyzed and the results are presented in this paper. The great potential of two dimensional NMR and ESI tandem mass spectrometry was harnessed during the course of peptide characterizations. A new RP-HPLC method for the analysis of trifluor...

  15. Peptides, polypeptides and peptide-polymer hybrids as nucleic acid carriers.

    Science.gov (United States)

    Ahmed, Marya

    2017-10-24

    Cell penetrating peptides (CPPs), and protein transduction domains (PTDs) of viruses and other natural proteins serve as a template for the development of efficient peptide based gene delivery vectors. PTDs are sequences of acidic or basic amphipathic amino acids, with superior membrane trespassing efficacies. Gene delivery vectors derived from these natural, cationic and cationic amphipathic peptides, however, offer little flexibility in tailoring the physicochemical properties of single chain peptide based systems. Owing to significant advances in the field of peptide chemistry, synthetic mimics of natural peptides are often prepared and have been evaluated for their gene expression, as a function of amino acid functionalities, architecture and net cationic content of peptide chains. Moreover, chimeric single polypeptide chains are prepared by a combination of multiple small natural or synthetic peptides, which imparts distinct physiological properties to peptide based gene delivery therapeutics. In order to obtain multivalency and improve the gene delivery efficacies of low molecular weight cationic peptides, bioactive peptides are often incorporated into a polymeric architecture to obtain novel 'polymer-peptide hybrids' with improved gene delivery efficacies. Peptide modified polymers prepared by physical or chemical modifications exhibit enhanced endosomal escape, stimuli responsive degradation and targeting efficacies, as a function of physicochemical and biological activities of peptides attached onto a polymeric scaffold. The focus of this review is to provide comprehensive and step-wise progress in major natural and synthetic peptides, chimeric polypeptides, and peptide-polymer hybrids for nucleic acid delivery applications.

  16. Development and use of engineered peptide deformylase in chemoenzymatic peptide synthesis

    NARCIS (Netherlands)

    Di Toma, Claudia

    2012-01-01

    Deze thesis beschrijft het onderzoek naar potentieel van het gebruik van het peptide deformylase (PDF) in chemo enzymatische peptide synthese. PDF is geschikt voor selective N terminale deformylatie van bepaalde N-formyl-peptides zonder gelijktijdige hydrolyse van de peptide binding. Door de

  17. Modeling of the Ebola Virus Delta Peptide Reveals a Potential Lytic Sequence Motif

    Directory of Open Access Journals (Sweden)

    William R. Gallaher

    2015-01-01

    Full Text Available Filoviruses, such as Ebola and Marburg viruses, cause severe outbreaks of human infection, including the extensive epidemic of Ebola virus disease (EVD in West Africa in 2014. In the course of examining mutations in the glycoprotein gene associated with 2014 Ebola virus (EBOV sequences, a differential level of conservation was noted between the soluble form of glycoprotein (sGP and the full length glycoprotein (GP, which are both encoded by the GP gene via RNA editing. In the region of the proteins encoded after the RNA editing site sGP was more conserved than the overlapping region of GP when compared to a distant outlier species, Tai Forest ebolavirus. Half of the amino acids comprising the “delta peptide”, a 40 amino acid carboxy-terminal fragment of sGP, were identical between otherwise widely divergent species. A lysine-rich amphipathic peptide motif was noted at the carboxyl terminus of delta peptide with high structural relatedness to the cytolytic peptide of the non-structural protein 4 (NSP4 of rotavirus. EBOV delta peptide is a candidate viroporin, a cationic pore-forming peptide, and may contribute to EBOV pathogenesis.

  18. Impact of microencapsulated peptidase (Aspergillus oryzae) on cheddar cheese proteolysis and its biologically active peptide profile.

    Science.gov (United States)

    Seneweera, Saman; Kailasapathy, Kaila

    2011-07-01

    We investigated the delivery of calcium-alginate encapsulated peptidase (Flavourzyme(®), Aspergillus oryzae) on proteolysis of Cheddar cheese. Physical and chemical characteristics such as moisture, pH and fat content were measured, and no differences were found between control and experimental cheese at day 0. SDS-PAGE analysis clearly showed that proteolysis of α and k casein was significantly accelerated after three months of maturity in the experimental cheese. A large number of low molecular weight peptides were found in the water soluble fraction of the experimental cheeses and some of these peptides were new. N-terminal amino acid sequence analysis identified these as P(1), Leu-Thu-Glu; P(3), Asp-Val-Pro-Ser-Glu) and relatively abundant stable peptides P(2), P(4), Arg-Pro-Lys-His-Pro-Ile; P(5), Arg-Pro-Lys-His-Pro-Ile-Lys and P(6). These peptides were mainly originated from αs1-CN and β-CN. Three of the identified peptides (P(1), P(2), P(3) and P(4)) are known to biologically active and P(1) and P(3) were only present in experimental cheese suggesting that experimental cheese has improved health benefits.

  19. Oxidative Modification of Tryptophan-Containing Peptides

    DEFF Research Database (Denmark)

    Petersen, Jonas; Christensen, Pia Katrine; Nielsen, Mathias T

    2018-01-01

    We herein present a broadly useful method for the chemoselective modification of a wide range of tryptophan-containing peptides. Exposing a tryptophan-containing peptide to 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) resulted in a selective cyclodehydration between the peptide backbone...

  20. Synthetic Procedures for Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  1. A novel multidimensional protein identification technology approach combining protein size exclusion prefractionation, peptide zwitterion-ion hydrophilic interaction chromatography, and nano-ultraperformance RP chromatography/nESI-MS2 for the in-depth analysis of the serum proteome and phosphoproteome: application to clinical sera derived from humans with benign prostate hyperplasia.

    Science.gov (United States)

    Garbis, Spiros D; Roumeliotis, Theodoros I; Tyritzis, Stavros I; Zorpas, Kostas M; Pavlakis, Kitty; Constantinides, Constantinos A

    2011-02-01

    The current proof-of-principle study was aimed toward development of a novel multidimensional protein identification technology (MudPIT) approach for the in-depth proteome analysis of human serum derived from patients with benign prostate hyperplasia (BPH) using rational chromatographic design principles. This study constituted an extension of our published work relating to the identification and relative quantification of potential clinical biomarkers in BPH and prostate cancer (PCa) tissue specimens. The proposed MudPIT approach encompassed the use of three distinct yet complementary liquid chromatographic chemistries. High-pressure size-exclusion chromatography (SEC) was used for the prefractionation of serum proteins followed by their dialysis exchange and solution phase trypsin proteolysis. The tryptic peptides were then subjected to offline zwitterion-ion hydrophilic interaction chromatography (ZIC-HILIC) fractionation followed by their online analysis with reversed-phase nano-ultraperformance chromatography (RP-nUPLC) hyphenated to nanoelectrospray ionization-tandem mass spectrometry using an ion trap mass analyzer. For the spectral processing, the sequential use of the SpectrumMill, Scaffold, and InsPecT software tools was applied for the tryptic peptide product ion MS(2) spectral processing, false discovery rate (FDR) assessment, validation, and protein identification. This milestone serum analysis study allowed the confident identification of over 1955 proteins (p ≤ 0.05; FDR ≤ 5%) with a broad spectrum of biological and physicochemical properties including secreted, tissue-specific proteins spanning approximately 12 orders of magnitude as they occur in their native abundance levels in the serum matrix. Also encompassed in this proteome was the confident identification of 375 phosphoproteins (p ≤ 0.05; FDR ≤ 5%) with potential importance to cancer biology. To demonstrate the performance characteristics of this novel MudPIT approach, a comparison

  2. Revisiting Hansen Solubility Parameters by Including Thermodynamics

    NARCIS (Netherlands)

    Louwerse, Manuel J; Fernández-Maldonado, Ana María; Rousseau, Simon; Moreau-Masselon, Chloe; Roux, Bernard; Rothenberg, Gadi

    2017-01-01

    The Hansen solubility parameter approach is revisited by implementing the thermodynamics of dissolution and mixing. Hansen's pragmatic approach has earned its spurs in predicting solvents for polymer solutions, but for molecular solutes improvements are needed. By going into the details of entropy

  3. Solubility of hydrogen in delta iron

    International Nuclear Information System (INIS)

    Shapovalov, V.I.; Trofimenko, V.V.

    1979-01-01

    The solubility of hydrogen in iron (less than 0.002 % impurities) at temperatures of 800-1510 deg C and a pressure of 100 atm was measured. The heat of solution of hydrogen in delta-Fe, equal to 73 kJ/g-atom, is by far greater than the corresponding values for α- and γ-Fe

  4. Solubility of ethylene in methyl propionate

    NARCIS (Netherlands)

    Shariati - Sarabi, A.; Florusse, L.J.; Peters, C.J.

    2015-01-01

    In this work, the solubility of ethylene in methyl propionate was measured within a temperature range of 283.5–464.8 K and pressures up to 10.7 MPa. Experiments were carried out using the Cailletet apparatus, which uses a synthetic method for the experiments. The critical points of several isopleths

  5. Radiculography with water-soluble contraste medium

    International Nuclear Information System (INIS)

    Araujo Pinheiro, R.S. de

    1987-01-01

    The etiologic diagnosis of the lumbar pain is discussed. The radiculography with water-soluble contrast medium is used and 250 cases are studied. Some practical criteria of indication executation and interpretation of the examination are reported. (M.A.C.) [pt

  6. Solubility of heavy metals added to MSW

    International Nuclear Information System (INIS)

    Lo, H.M.; Lin, K.C.; Liu, M.H.; Pai, T.Z.; Lin, C.Y.; Liu, W.F.; Fang, G.C.; Lu, C.; Chiang, C.F.; Wang, S.C.; Chen, P.H.; Chen, J.K.; Chiu, H.Y.; Wu, K.C.

    2009-01-01

    This paper aims to investigate the six heavy metal levels (Cd, Cr, Cu, Pb, Ni and Zn) in municipal solid waste (MSW) at different pHs. It intends to provide the baseline information of metals solubility in MSW co-disposed or co-digested with MSW incinerator ashes in landfill or anaerobic bioreactors or heavy metals contaminated in anaerobic digesters. One milliliter (equal to 1 mg) of each metal was added to the 100 ml MSW and the batch reactor test was carried out. The results showed that higher HNO 3 and NaOH were consumed at extreme pH of 1 and 13 compared to those from pH 2 to 11 due to the comparably higher buffer capacity. Pb was found to have the least soluble level, highest metal adsorption (%) and highest partitioning K d (l g -1 ) between pH 3 and 12. In contrast, Ni showed the highest soluble level, lowest metal adsorption (%) and lowest K d (l g -1 ) between pH 4 and 12. Except Ni and Cr, other four metals seemed to show the amphibious properties as comparative higher solubility was found in the acidic and basic conditions

  7. Solubility of heavy metals added to MSW

    Energy Technology Data Exchange (ETDEWEB)

    Lo, H.M. [Department of Environmental Engineering and Management, Chaoyang University of Technology, 168 Gifong E. Road, Wufong, Taichung County 41349, Taiwan (China)], E-mail: hmlo@cyut.edu.tw; Lin, K.C. [Department of Occupational Safety and Health, Chung Shan Medical University, 110, Sec. 1, Jiangguo N. Rd., Taichung 402, Taiwan (China); Liu, M.H.; Pai, T.Z. [Department of Environmental Engineering and Management, Chaoyang University of Technology, 168 Gifong E. Road, Wufong, Taichung County 41349, Taiwan (China); Lin, C.Y. [Department of Soil and Water Conservation, Chung Hsing University, 250 Kuokuang Road, Taichung 402, Taiwan (China); Liu, W.F. [Department of Electronical Engineering, Feng Chia University, 100 Wenhwa Road, Taichung 407, Taiwan (China); Fang, G.C. [Department of Environmental Engineering, Hungkuang University, 34 Chung-Chie Road, Sha Lu, Taichung 433, Taiwan (China); Lu, C. [Department of Environmental Engineering, Chung Hsing University, 250 Kuokuang Road, Taichung 402, Taiwan (China); Chiang, C.F. [Department of Health Risk Management, China Medical University, No. 91 Hsueh-Shih Road, Taichung 40402, Taiwan (China); Wang, S.C.; Chen, P.H.; Chen, J.K.; Chiu, H.Y.; Wu, K.C. [Department of Environmental Engineering and Management, Chaoyang University of Technology, 168 Gifong E. Road, Wufong, Taichung County 41349, Taiwan (China)

    2009-01-15

    This paper aims to investigate the six heavy metal levels (Cd, Cr, Cu, Pb, Ni and Zn) in municipal solid waste (MSW) at different pHs. It intends to provide the baseline information of metals solubility in MSW co-disposed or co-digested with MSW incinerator ashes in landfill or anaerobic bioreactors or heavy metals contaminated in anaerobic digesters. One milliliter (equal to 1 mg) of each metal was added to the 100 ml MSW and the batch reactor test was carried out. The results showed that higher HNO{sub 3} and NaOH were consumed at extreme pH of 1 and 13 compared to those from pH 2 to 11 due to the comparably higher buffer capacity. Pb was found to have the least soluble level, highest metal adsorption (%) and highest partitioning K{sub d} (l g{sup -1}) between pH 3 and 12. In contrast, Ni showed the highest soluble level, lowest metal adsorption (%) and lowest K{sub d} (l g{sup -1}) between pH 4 and 12. Except Ni and Cr, other four metals seemed to show the amphibious properties as comparative higher solubility was found in the acidic and basic conditions.

  8. Anomalous Solubility Behavior of Several Acidic Drugs

    Directory of Open Access Journals (Sweden)

    Alex Avdeef

    2014-04-01

    Full Text Available The “anomalous solubility behavior at higher pH values” of several acidic drugs originally studied by Higuchi et al. in 1953 [1], but hitherto not fully rationalized, has been re-analyzed using a novel solubility-pH analysis computer program, pDISOL-XTM. The program internally derives implicit solubility equations, given a set of proposed equilibria and constants (iteratively refined by weighted nonlinear regression, and does not require explicit Henderson-Hasselbalch equations. The re-analyzed original barbital, phenobarbital, oxytetracycline, and sulfathiazole solubility-pH data of Higuchi et al. is consistent with the presence of dimers in saturated solutions. In the case of barbital, phenobarbital and sulfathiazole, anionic dimers, reaching peak concentrations near pH 8. However, oxytetracycline indicated a pronounced tendency to form a cationic dimer, peaking near pH 2. Under the conditions of the original study, only barbital indicated a slight tendency to form a salt precipitate at pH > 6.8, with a highly unusual stoichiometry (consistent with a slope of 0.55 in the log S – pH plot: K+ + A2H- + 3HA D KA5H4(s. Thus the “anomaly” in the Higuchi data can be rationalized by invoking specific aggregated species.

  9. Changes in protein solubility, fermentative capacity, viscoelasticity ...

    African Journals Online (AJOL)

    Frozen dough should be stored for fewer than 21 days; time in which the loaf volume of bread made from frozen dough was approximately 40.84% smaller than that of fresh bread dough formulation. Keywords: French type bread, frozen dough, protein solubility, baking quality, viscoelasticity. African Journal of Biotechnology ...

  10. Role of Soluble Innate Effector Molecules in Pulmonary Defense against Fungal Pathogens

    Directory of Open Access Journals (Sweden)

    Soledad R. Ordonez

    2017-10-01

    Full Text Available Fungal infections of the lung are life-threatening but rarely occur in healthy, immunocompetent individuals, indicating efficient clearance by pulmonary defense mechanisms. Upon inhalation, fungi will first encounter the airway surface liquid which contains several soluble effector molecules that form the first barrier of defense against fungal infections. These include host defense peptides, like LL-37 and defensins that can neutralize fungi by direct killing of the pathogen, and collectins, such as surfactant protein A and D, that can aggregate fungi and stimulate phagocytosis. In addition, these molecules have immunomodulatory activities which can aid in fungal clearance from the lung. However, existing observations are based on in vitro studies which do not reflect the complexity of the lung and its airway surface liquid. Ionic strength, pH, and the presence of mucus can have strong detrimental effects on antifungal activity, while the potential synergistic interplay between soluble effector molecules is largely unknown. In this review, we describe the current knowledge on soluble effector molecules that contribute to antifungal activity, the importance of environmental factors and discuss the future directions required to understand the innate antifungal defense in the lung.

  11. Role of Soluble Innate Effector Molecules in Pulmonary Defense against Fungal Pathogens

    Science.gov (United States)

    Ordonez, Soledad R.; Veldhuizen, Edwin J. A.; van Eijk, Martin; Haagsman, Henk P.

    2017-01-01

    Fungal infections of the lung are life-threatening but rarely occur in healthy, immunocompetent individuals, indicating efficient clearance by pulmonary defense mechanisms. Upon inhalation, fungi will first encounter the airway surface liquid which contains several soluble effector molecules that form the first barrier of defense against fungal infections. These include host defense peptides, like LL-37 and defensins that can neutralize fungi by direct killing of the pathogen, and collectins, such as surfactant protein A and D, that can aggregate fungi and stimulate phagocytosis. In addition, these molecules have immunomodulatory activities which can aid in fungal clearance from the lung. However, existing observations are based on in vitro studies which do not reflect the complexity of the lung and its airway surface liquid. Ionic strength, pH, and the presence of mucus can have strong detrimental effects on antifungal activity, while the potential synergistic interplay between soluble effector molecules is largely unknown. In this review, we describe the current knowledge on soluble effector molecules that contribute to antifungal activity, the importance of environmental factors and discuss the future directions required to understand the innate antifungal defense in the lung. PMID:29163395

  12. Solubility of Tc(IV) oxides

    International Nuclear Information System (INIS)

    Liu, D.J.; Fan, X.H.

    2005-01-01

    Full text of publication follows: The deep geological disposal of the high level radioactive wastes is expected to be a safer disposal method in most countries. The long-lived fission product 99 Tc is present in large quantities in nuclear wastes and its chemical behavior in aqueous solution is of considerable interest. Under the reducing conditions, expected to exist in a deep geological repository, it is generally predicted that technetium will be present as TcO 2 .nH 2 O. The solubility of Tc(IV) is used as a source term in performance assessment of radioactive waste repository. Technetium oxide was prepared by reduction of a technetate solution with Sn 2+ . The solubility of Tc(IV) oxide has been determined in simulated groundwater and re-distilled water under aerobic and anaerobic conditions. The effects of pH and CO 3 2- concentration of solution on solubility of Tc(IV) oxide were studied. The concentration of total technetium and Tc(IV) species in the solutions were periodically determined by separating the oxidized and reduced technetium species using a solvent extraction procedure and counting the beta activity of the 99 Tc with a liquid scintillation counter. The experimental results show that the rate of oxidation of Tc(IV) in simulated groundwater and re-distilled water is about (1.49∼1.86) x 10 -9 mol/(L.d) under aerobic conditions, but Tc(IV) in simulated groundwater and re-distilled water is not oxidized under anaerobic conditions. Under aerobic or anaerobic conditions the solubility of Tc(IV) oxide in simulated groundwater and re-distilled water is equal on the whole after centrifugation or ultrafiltration. The solubility of Tc(IV) oxide decreases with the increase of pH at pH 10 and is pH independent in the range 2 -8 to 10 -9 mol/L at 2 3 2- concentration. These data could be used to estimate the Tc(IV) solubility for cases where solubility limits transport of technetium in reducing environments of high-level waste repositories. (authors)

  13. Scoring function to predict solubility mutagenesis

    Directory of Open Access Journals (Sweden)

    Deutsch Christopher

    2010-10-01

    Full Text Available Abstract Background Mutagenesis is commonly used to engineer proteins with desirable properties not present in the wild type (WT protein, such as increased or decreased stability, reactivity, or solubility. Experimentalists often have to choose a small subset of mutations from a large number of candidates to obtain the desired change, and computational techniques are invaluable to make the choices. While several such methods have been proposed to predict stability and reactivity mutagenesis, solubility has not received much attention. Results We use concepts from computational geometry to define a three body scoring function that predicts the change in protein solubility due to mutations. The scoring function captures both sequence and structure information. By exploring the literature, we have assembled a substantial database of 137 single- and multiple-point solubility mutations. Our database is the largest such collection with structural information known so far. We optimize the scoring function using linear programming (LP methods to derive its weights based on training. Starting with default values of 1, we find weights in the range [0,2] so that predictions of increase or decrease in solubility are optimized. We compare the LP method to the standard machine learning techniques of support vector machines (SVM and the Lasso. Using statistics for leave-one-out (LOO, 10-fold, and 3-fold cross validations (CV for training and prediction, we demonstrate that the LP method performs the best overall. For the LOOCV, the LP method has an overall accuracy of 81%. Availability Executables of programs, tables of weights, and datasets of mutants are available from the following web page: http://www.wsu.edu/~kbala/OptSolMut.html.

  14. Molybdenum solubility in aluminium nitrate solutions

    Energy Technology Data Exchange (ETDEWEB)

    Heres, X.; Sans, D.; Bertrand, M.; Eysseric, C. [CEA, Centre de Marcoule, Nuclear Energy Division, DRCP, BP 17171, 30207 Bagnols-sur-Ceze Cedex (France); Brackx, E.; Domenger, R.; Excoffier, E. [CEA, Centre de Marcoule, Nuclear Energy Division, DTEC, BP 17171, 30207 Bagnols-sur-Ceze Cedex (France); Valery, J.F. [AREVA-NC, DOR/RDP, Paris - La Defense (France)

    2016-07-01

    For over 60 years, research reactors (RR or RTR for research testing reactors) have been used as neutron sources for research, radioisotope production ({sup 99}Mo/{sup 99m}Tc), nuclear medicine, materials characterization, etc... Currently, over 240 of these reactors are in operation in 56 countries. They are simpler than power reactors and operate at lower temperature (cooled to below 100 C. degrees). The fuel assemblies are typically plates or cylinders of uranium alloy and aluminium (U-Al) coated with pure aluminium. These fuels can be processed in AREVA La Hague plant after batch dissolution in concentrated nitric acid and mixing with UOX fuel streams. The aim of this study is to accurately measure the solubility of molybdenum in nitric acid solution containing high concentrations of aluminium. The higher the molybdenum solubility is, the more flexible reprocessing operations are, especially when the spent fuels contain high amounts of molybdenum. To be most representative of the dissolution process, uranium-molybdenum alloy and molybdenum metal powder were dissolved in solutions of aluminium nitrate at the nominal dissolution temperature. The experiments showed complete dissolution of metallic elements after 30 minutes long stirring, even if molybdenum metal was added in excess. After an induction period, a slow precipitation of molybdic acid occurs for about 15 hours. The data obtained show the molybdenum solubility decreases with increasing aluminium concentration. The solubility law follows an exponential relation around 40 g/L of aluminium with a high determination coefficient. Molybdenum solubility is not impacted by the presence of gadolinium, or by an increasing concentration of uranium. (authors)

  15. Insect Peptides - Perspectives in Human Diseases Treatment.

    Science.gov (United States)

    Chowanski, Szymon; Adamski, Zbigniew; Lubawy, Jan; Marciniak, Pawel; Pacholska-Bogalska, Joanna; Slocinska, Malgorzata; Spochacz, Marta; Szymczak, Monika; Urbanski, Arkadiusz; Walkowiak-Nowicka, Karolina; Rosinski, Grzegorz

    2017-01-01

    Insects are the largest and the most widely distributed group of animals in the world. Their diversity is a source of incredible variety of different mechanisms of life processes regulation. There are many agents that regulate immunology, reproduction, growth and development or metabolism. Hence, it seems that insects may be a source of numerous substances useful in human diseases treatment. Especially important in the regulation of insect physiology are peptides, like neuropeptides, peptide hormones or antimicrobial peptides. There are two main aspects where they can be helpful, 1) Peptides isolated from insects may become potential drugs in therapy of different diseases, 2) A lot of insect peptide hormones show structural or functional homology to mammalian peptide hormones and the comparative studies may give a new look on human disorders. In our review we focused on three group of insect derived peptides: 1) immune-active peptides, 2) peptide hormones and 3) peptides present in venoms. In our review we try to show the considerable potential of insect peptides in searching for new solutions for mammalian diseases treatment. We summarise the knowledge about properties of insect peptides against different virulent agents, anti-inflammatory or anti-nociceptive properties as well as compare insect and mammalian/vertebrate peptide endocrine system to indicate usefulness of knowledge about insect peptide hormones in drug design. The field of possible using of insect delivered peptide to therapy of various human diseases is still not sufficiently explored. Undoubtedly, more attention should be paid to insects due to searching new drugs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  16. Beta-endorphin chimeric peptides: Transport through the blood-brain barrier in vivo and cleavage of disulfide linkage by brain

    International Nuclear Information System (INIS)

    Pardridge, W.M.; Triguero, D.; Buciak, J.L.

    1990-01-01

    Water soluble peptides are normally not transported through the blood-brain barrier (BBB). Chimeric peptides may be transportable through the BBB and are formed by the covalent coupling of a nontransportable peptide to a transportable peptide vector, e.g. cationized albumin, using disulfide-based coupling reagents such as N-succinimidyl 3-[2-pyridyldithio(propionate)] (SPDP). The transcytosis of peptide into brain parenchyma, as opposed to vascular sequestration of blood-borne peptide, was quantified using an internal carotid artery perfusion/capillary depletion method. It is shown that [125I]beta-endorphin is not transported through the BBB, but is rapidly cleaved to free [125I] tyrosine via capillary peptidase. Therefore, chimeric peptide was prepared using [125I] [D-Ala2]beta-endorphin (DABE), owing to the resistance of this analogue to peptidase degradation. The [125I] DABE-cationized albumin chimeric peptide is shown to enter brain parenchyma at a rate comparable to that reported previously for unconjugated cationized albumin. When the [125I] DABE-cationized albumin chimeric peptide was incubated with rat brain homogenate at 37 C, the free [125I] DABE was liberated from the cationized albumin conjugate prior to its subsequent degradation into free [125I] tyrosine. Approximately 50% of the chimeric peptide was cleaved within 60 sec of incubation at 37 C. These studies demonstrate that (1) [125I]beta-endorphin is not transported through the BBB in its unconjugated form, (2) a [125I] DABE-cationized albumin chimeric peptide is transported through the BBB into brain parenchyma at a rate comparable to the unconjugated cationized albumin, and (3) brain contains the necessary disulfide reductases for rapid cleavage of the chimeric peptide into free beta-endorphin and this cleavage occurs before degradation of the [125I] DABE into [125I] tyrosine

  17. Beta-endorphin chimeric peptides: Transport through the blood-brain barrier in vivo and cleavage of disulfide linkage by brain

    Energy Technology Data Exchange (ETDEWEB)

    Pardridge, W.M.; Triguero, D.; Buciak, J.L. (UCLA School of Medicine (USA))

    1990-02-01

    Water soluble peptides are normally not transported through the blood-brain barrier (BBB). Chimeric peptides may be transportable through the BBB and are formed by the covalent coupling of a nontransportable peptide to a transportable peptide vector, e.g. cationized albumin, using disulfide-based coupling reagents such as N-succinimidyl 3-(2-pyridyldithio(propionate)) (SPDP). The transcytosis of peptide into brain parenchyma, as opposed to vascular sequestration of blood-borne peptide, was quantified using an internal carotid artery perfusion/capillary depletion method. It is shown that (125I)beta-endorphin is not transported through the BBB, but is rapidly cleaved to free (125I) tyrosine via capillary peptidase. Therefore, chimeric peptide was prepared using (125I) (D-Ala2)beta-endorphin (DABE), owing to the resistance of this analogue to peptidase degradation. The (125I) DABE-cationized albumin chimeric peptide is shown to enter brain parenchyma at a rate comparable to that reported previously for unconjugated cationized albumin. When the (125I) DABE-cationized albumin chimeric peptide was incubated with rat brain homogenate at 37 C, the free (125I) DABE was liberated from the cationized albumin conjugate prior to its subsequent degradation into free (125I) tyrosine. Approximately 50% of the chimeric peptide was cleaved within 60 sec of incubation at 37 C. These studies demonstrate that (1) (125I)beta-endorphin is not transported through the BBB in its unconjugated form, (2) a (125I) DABE-cationized albumin chimeric peptide is transported through the BBB into brain parenchyma at a rate comparable to the unconjugated cationized albumin, and (3) brain contains the necessary disulfide reductases for rapid cleavage of the chimeric peptide into free beta-endorphin and this cleavage occurs before degradation of the (125I) DABE into (125I) tyrosine.

  18. Peptides: Production, bioactivity, functionality, and applications

    DEFF Research Database (Denmark)

    Hajfathalian, Mona; Ghelichi, Sakhi; García Moreno, Pedro Jesús

    2017-01-01

    Production of peptides with various effects from proteins of different sources continues to receive academic attention. Researchers of different disciplines are putting increasing efforts to produce bioactive and functional peptides from different sources such as plants, animals, and food industry...... by-products. The aim of this review is to introduce production methods of hydrolysates and peptides and provide a comprehensive overview of their bioactivity in terms of their effects on immune, cardiovascular, nervous, and gastrointestinal systems. Moreover, functional and antioxidant properties...... of hydrolysates and isolated peptides are reviewed. Finally, industrial and commercial applications of bioactive peptides including their use in nutrition and production of pharmaceuticals and nutraceuticals are discussed....

  19. Natriuretic peptides in cardiometabolic regulation and disease

    DEFF Research Database (Denmark)

    Zois, Nora E; Bartels, Emil D; Hunter, Ingrid

    2014-01-01

    decade. Dysregulation of the natriuretic peptide system has been associated with obesity, glucose intolerance, type 2 diabetes mellitus, and essential hypertension. Moreover, the natriuretic peptides have been implicated in the protection against atherosclerosis, thrombosis, and myocardial ischaemia. All...... these conditions can coexist and potentially lead to heart failure, a syndrome associated with a functional natriuretic peptide deficiency despite high circulating concentrations of immunoreactive peptides. Therefore, dysregulation of the natriuretic peptide system, a 'natriuretic handicap', might be an important...... factor in the initiation and progression of metabolic dysfunction and its accompanying cardiovascular complications. This Review provides a summary of the natriuretic peptide system and its involvement in these cardiometabolic conditions. We propose that these peptides might have an integrating role...

  20. Determination of radionuclide solubility limits to be used in SR 97. Uncertainties associated to calculated solubilities

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, J.; Cera, E.; Duro, L.; Jordana, S. [QuantiSci S.L., Barcelona (Spain); Pablo, J. de [DEQ-UPC, Barcelona (Spain); Savage, D. [QuantiSci Ltd., Henley-on-Thames (United Kingdom)

    1997-12-01

    The thermochemical behaviour of 24 critical radionuclides for the forthcoming SR97 PA exercise is discussed. The available databases are reviewed and updated with new data and an extended database for aqueous and solid species of the radionuclides of interest is proposed. We have calculated solubility limits for the radionuclides of interest under different groundwater compositions. A sensitivity analysis of the calculated solubilities with the composition of the groundwater is presented. Besides selecting the most likely solubility limiting phases, in this work we have used coprecipitation approaches in order to calculate more realistic solubility limits for minor radionuclides, such as Ra, Am and Cm. The comparison between the calculated solubilities and the concentrations measured in relevant natural systems (NA) and in spent fuel leaching experiments helps to assess the validity of the methodology used and to derive source term concentrations for the radionuclides studied. The uncertainties associated to the solubilities of the main radionuclides involved in the spent nuclear fuel have also been discussed in this work. The variability of the groundwater chemistry; redox conditions and temperature of the system have been considered the main factors affecting the solubilities. In this case, a sensitivity analysis has been performed in order to study solubility changes as a function of these parameters. The uncertainties have been calculated by including the values found in a major extent in typical granitic groundwaters. The results obtained from this analysis indicate that there are some radionuclides which are not affected by these parameters, i.e. Ag, Cm, Ho, Nb, Ni, Np, Pu, Se, Sm, Sn, Sr, Tc and U

  1. Solubility behavior and biopharmaceutical classification of novel high-solubility ciprofloxacin and norfloxacin pharmaceutical derivatives.

    Science.gov (United States)

    Breda, Susana A; Jimenez-Kairuz, Alvaro F; Manzo, Ruben H; Olivera, María E

    2009-04-17

    The hydrochlorides of the 1:3 aluminum:norfloxacin and aluminum:ciprofloxacin complexes were characterized according to the Biopharmaceutics Classification System (BCS) premises in comparison with their parent compounds. The pH-solubility profiles of the complexes were experimentally determined at 25 and 37 degrees C in the range of pH 1-8 and compared to that of uncomplexed norfloxacin and ciprofloxacin. Both complexes are clearly more soluble than the antibiotics themselves, even at the lowest solubility pHs. The increase in solubility was ascribed to the species controlling solubility, which were analyzed in the solid phases at equilibrium at selected pHs. Additionally, permeability was set as low, based on data reported in the scientific literature regarding oral bioavailability, intestinal and cell cultures permeabilities and also considering the influence of stoichiometric amounts of aluminum. The complexes fulfill the BCS criterion to be classified as class 3 compounds (high solubility/low permeability). Instead, the active pharmaceutical ingredients (APIs) currently used in solid dosage forms, norfloxacin and ciprofloxacin hydrochloride, proved to be BCS class 4 (low solubility/low permeability). The solubility improvement turns the complexes as potential biowaiver candidates from the scientific point of view and may be a good way for developing more dose-efficient formulations. An immediate release tablet showing very rapid dissolution was obtained. Its dissolution profile was compared to that of the commercial ciprofloxacin hydrochloride tablets allowing to dissolution of the complete dose at a critical pH such as 6.8.

  2. Effect of Cyclodextrin Complexation on the Aqueous Solubility and Solubility/Dose Ratio of Praziquantel

    OpenAIRE

    Maragos, Stratos; Archontaki, Helen; Macheras, Panos; Valsami, Georgia

    2009-01-01

    Praziquantel (PZQ), the primary drug of choice in the treatment of schistosomiasis, is a highly lipophilic drug that possesses high permeability and low aqueous solubility and is, therefore, classified as a Class II drug according to the Biopharmaceutics Classification System (BCS). In this work, β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) were used in order to determine whether increasing the aqueous solubility of a drug by complexation with CDs, a BCS-Class II compound ...

  3. Novel electrosprayed nanospherules for enhanced aqueous solubility and oral bioavailability of poorly water-soluble fenofibrate.

    Science.gov (United States)

    Yousaf, Abid Mehmood; Mustapha, Omer; Kim, Dong Wuk; Kim, Dong Shik; Kim, Kyeong Soo; Jin, Sung Giu; Yong, Chul Soon; Youn, Yu Seok; Oh, Yu-Kyoung; Kim, Jong Oh; Choi, Han-Gon

    2016-01-01

    The purpose of the present research was to develop a novel electrosprayed nanospherule providing the most optimized aqueous solubility and oral bioavailability for poorly water-soluble fenofibrate. Numerous fenofibrate-loaded electrosprayed nanospherules were prepared with polyvinylpyrrolidone (PVP) and Labrafil(®) M 2125 as carriers using the electrospray technique, and the effect of the carriers on drug solubility and solvation was assessed. The solid state characterization of an optimized formulation was conducted by scanning electron microscopy, powder X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopic analyses. Oral bioavailability in rats was also evaluated for the formulation of an optimized nanospherule in comparison with free drug and a conventional fenofibrate-loaded solid dispersion. All of the electrosprayed nanospherule formulations had remarkably enhanced aqueous solubility and dissolution compared with free drug. Moreover, Labrafil M 2125, a surfactant, had a positive influence on the solubility and dissolution of the drug in the electrosprayed nanospherule. Increases were observed as the PVP/drug ratio increased to 4:1, but higher ratios gave no significant increases. In particular, an electrosprayed nanospherule composed of fenofibrate, PVP, and Labrafil M 2125 at the weight ratio of 1:4:0.5 resulted in a particle size of water-soluble fenofibrate.

  4. Two novel solvent system compositions for protected synthetic peptide purification by centrifugal partition chromatography.

    Science.gov (United States)

    Amarouche, Nassima; Giraud, Matthieu; Forni, Luciano; Butte, Alessandro; Edwards, F; Borie, Nicolas; Renault, Jean-Hugues

    2014-04-11

    Protected synthetic peptide intermediates are often hydrophobic and not soluble in most common solvents. They are thus difficult to purify by preparative reversed-phase high-performance liquid chromatography (RP-HPLC), usually used for industrial production. It is then challenging to develop alternative chromatographic purification processes. Support-free liquid-liquid chromatographic techniques, including both hydrostatic (centrifugal partition chromatography or CPC) and hydrodynamic (counter-current chromatography or CCC) devices, are mainly involved in phytochemical studies but have also been applied to synthetic peptide purification. In this framework, two new biphasic solvent system compositions covering a wide range of polarity were developed to overcome solubility problems mentioned above. The new systems composed of heptane/tetrahydrofuran/acetonitrile/dimethylsulfoxide/water and heptane/methyl-tetrahydrofuran/N-methylpyrrolidone/water were efficiently used for the CPC purification of a 39-mer protected exenatide (Byetta®) and a 8-mer protected peptide intermediate of bivalirudin (Angiox®) synthesis. Phase compositions of the different biphasic solvent systems were determined by (1)H nuclear magnetic resonance. Physico-chemical properties including viscosity, density and interfacial tension of these biphasic systems are also described. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Alzheimer's disease against peptides products of enzymatic cleavage APP protein: Biological, pathobiological and physico-chemical properties of fibrillating peptides.

    Science.gov (United States)

    Marszałek, Małgorzata

    2017-05-17

    Various peptides products of enzymatic cleavage of key for Alzheimer's disease Amyloid Precursor Protein (APP) are well known, but still are matter of scientific debate. The Aβ type products are especially challenging for experimental and medical research. This paper outlines several, still poorly known, biological and medical processes such as peptides biology, i.e., formation, biodistribution, translocation, transport and finally removal from brain compartments and body fluids like Intracellular Fluid (ICF), Cerebrospinal Fluid (CSF), Interstitial Fluid (ISF), blood serum or urine. In addition, the following studies concerning AD patients might prove challenging and simultaneously promising: peptides translocation through Blood-Brain - Barrier (BBB) and Blood-Cerebrospinal Fluid Barrier (BCSFB) and their removal from the brain according to a new concept of glymphatic system; - diagnostic difficulties that stem from physico-chemical properties and the nature of proteins or fibrillating peptides itself like low concentration, short half-live and from experimental-technical problems as well like high adsorption or low solubility of Aβ, tau or amylin. The study of diagnostic parameters is very important, as it may better reflect early changes before the disease develops; one such parameter is the Aβ42/Aβ40 ratio, or the ratio with the total tau concentration combination and other new biomarkers like Aβ1-38; other factors include oxidative stress and inflammation process proteins, complement factor H, alpha-2-macroglobulin, or clusterin. The study of various forms of pathological amyloid deposits that emerge in different but specific brain regions AD patients seems to be crucial as well. The composition of the first initial pathological, pre-fibrillating monomers of fibrillating peptides and their role in AD development and disease progression have been described as well. They are even more challenging for science and simultaneously might be more promising in

  6. Complex formation and vectorization of a phosphorothioate oligonucleotide with an amphipathic leucine- and lysine-rich peptide: study at molecular and cellular levels.

    Science.gov (United States)

    Boukhalfa-Heniche, Fatima-Zohra; Hernández, Belén; Gaillard, Stéphane; Coïc, Yves-Marie; Huynh-Dinh, Tam; Lecouvey, Marc; Seksek, Olivier; Ghomi, Mahmoud

    2004-04-15

    Optical spectroscopic techniques such as CD, Raman scattering, and fluorescence imaging allowed us to analyze the complex formation and vectorization of a single-stranded 20-mer phosphorothioate oligodeoxynucleotide with a 15-mer amphipathic peptide at molecular and cellular levels. Different solvent mixtures (methanol and water) and molecular ratios of peptide/oligodeoxynucleotide complexes were tested in order to overcome the problems related to solubility. Optimal conditions for both spectroscopic and cellular experiments were obtained with the molecular ratio peptide/oligodeoxynucleotide equal to 21:4, corresponding to a 7:5 ratio for their respective +/- charge ratio. At the molecular level, CD and Raman spectra were consistent with a alpha-helix conformation of the peptide in water or in a methanol-water mixture. The presence of methanol increased considerably the solubility of the peptide without altering its alpha-helix conformation, as evidenced by CD and Raman spectroscopies. UV absorption melting profile of the oligodeoxynucleotide gave rise to a flat melting profile, corresponding to its random structure in solution. Raman spectra of oligodeoxynucleotide/peptide complexes could only be studied in methanol/water mixture solutions. Drastic changes observed in Raman spectra have undoubtedly shown: (a) the perturbation occurred in the peptide secondary structure, and (b) possible interaction between the lysine residues of the peptide and the oligodeoxynucleotide. At the cellular level, the complex was prepared in a mixture of 10% methanol and 90% cell medium. Cellular uptake in optimal conditions for the oligodeoxynucleotide delivery with low cytotoxicity was controlled by fluorescence imaging allowing to specifically locate the compacted oligonucleotide labeled with fluorescein at its 5'-terminus with the peptide into human glioma cells after 1 h of incubation at 37 degrees C. Copyright 2004 Wiley Periodicals, Inc.

  7. Analysis of peptide uptake and location of root hair-promoting peptide accumulation in plant roots.

    Science.gov (United States)

    Matsumiya, Yoshiki; Taniguchi, Rikiya; Kubo, Motoki

    2012-03-01

    Peptide uptake by plant roots from degraded soybean-meal products was analyzed in Brassica rapa and Solanum lycopersicum. B. rapa absorbed about 40% of the initial water volume, whereas peptide concentration was decreased by 75% after 24 h. Analysis by reversed-phase HPLC showed that number of peptides was absorbed by the roots during soaking in degraded soybean-meal products for 24 h. Carboxyfluorescein-labeled root hair-promoting peptide was synthesized, and its localization, movement, and accumulation in roots were investigated. The peptide appeared to be absorbed by root hairs and then moved to trichoblasts. Furthermore, the peptide was moved from trichoblasts to atrichoblasts after 24 h. The peptide was accumulated in epidermal cells, suggesting that the peptide may have a function in both trichoblasts and atrichoblasts. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.

  8. Taylor Dispersion Analysis as a promising tool for assessment of peptide-peptide interactions.

    Science.gov (United States)

    Høgstedt, Ulrich B; Schwach, Grégoire; van de Weert, Marco; Østergaard, Jesper

    2016-10-10

    Protein-protein and peptide-peptide (self-)interactions are of key importance in understanding the physiochemical behavior of proteins and peptides in solution. However, due to the small size of peptide molecules, characterization of these interactions is more challenging than for proteins. In this work, we show that protein-protein and peptide-peptide interactions can advantageously be investigated by measurement of the diffusion coefficient using Taylor Dispersion Analysis. Through comparison to Dynamic Light Scattering it was shown that Taylor Dispersion Analysis is well suited for the characterization of protein-protein interactions of solutions of α-lactalbumin and human serum albumin. The peptide-peptide interactions of three selected peptides were then investigated in a concentration range spanning from 0.5mg/ml up to 80mg/ml using Taylor Dispersion Analysis. The peptide-peptide interactions determination indicated that multibody interactions significantly affect the PPIs at concentration levels above 25mg/ml for the two charged peptides. Relative viscosity measurements, performed using the capillary based setup applied for Taylor Dispersion Analysis, showed that the viscosity of the peptide solutions increased with concentration. Our results indicate that a viscosity difference between run buffer and sample in Taylor Dispersion Analysis may result in overestimation of the measured diffusion coefficient. Thus, Taylor Dispersion Analysis provides a practical, but as yet primarily qualitative, approach to assessment of the colloidal stability of both peptide and protein formulations. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Radio peptide imaging and therapy

    International Nuclear Information System (INIS)

    Buscombe, Jonh

    1997-01-01

    Full text. The concept of the magic bullet retains its attraction to us. If only we could take a drug or radioisotope and inject this intravenously and then will attach to the target cancer. This may allow imaging if labelled with a radio pharmaceutical or possibly even effective therapy. Initially work was started using antibodies of mouse origin. These have shown some utility in targeting tumors but there are problems in that these are essentially non-human proteins, often derived from mice. This leads to the formation of antibodies against that antibody so that repeat administrations lead to reduced efficacy and possibly may carry a risk anaphylaxis for the patient. Two different methods have evolved to deal with this situation. Either make antibodies more human or use smaller fragments, so that they are less likely to cause allergic reactions. The second method is to try and use a synthetic peptide. This will contain a series of amino acids which recognize a certain cell receptor. For example the somatostatin analogue Octreotide is an 8 amino acid peptide which has the same biological actions as natural somatostatin but an increased plasma half life. To this is added a linker a good example being DTPA and then radioisotope for example In-111. There we can have the complex In-111-DTPA-Octreotide which can be used to image somatostatin receptors in vivo. The main advantage over antibodies is that the cost production is less and many different variation of peptides for a particular receptor can be manufactured and assessed to find which is the optimal agent tumour imaging at a fraction of the cost of antibody production. There are two main approaches. Firstly to take a natural peptide hormone such as insulin or VIP and label by a simple method such as iodination with I-123. A group in Vienna have done it and shown good uptake of I-123 Insulin in primary hepatomas and of I-123 VIP in pancreatic cancers. Many natural peptide hormones however have a short plasma half

  10. Solubility of cobalt in primary circuit solutions

    International Nuclear Information System (INIS)

    Lambert, I.; Joyer, F.

    1992-01-01

    The solubility of cobalt ferrite (CoFe 2 O 4 ) was measured in PWR primary circuit conditions, in the temperature range 250-350 deg C, and the results were compared with the ones obtained on magnetite and nickel ferrite. As in the former cases, it was found that, in the prevailing primary circuit conditions, the solubility of the cobalt ferrite was minimum at temperatures around 300 deg C, for cobalt as well as for iron. The equilibrium iron concentration is significantly lower than in the case of magnetite. The results are discussed in relation with the POTHY code, based only on thermodynamic laws and data, used for the prediction of the primary circuit chemistry

  11. Biochemical synthesis of water soluble conducting polymers

    Science.gov (United States)

    Bruno, Ferdinando F.; Bernabei, Manuele

    2016-05-01

    An efficient biomimetic route for the synthesis of conducting polymers/copolymers complexed with lignin sulfonate and sodium (polystyrenesulfonate) (SPS) will be presented. This polyelectrolyte assisted PEG-hematin or horseradish peroxidase catalyzed polymerization of pyrrole (PYR), 3,4 ethyldioxithiophene (EDOT) and aniline has provided a route to synthesize water-soluble conducting polymers/copolymers under acidic conditions. The UV-vis, FTIR, conductivity and cyclic voltammetry studies for the polymers/copolymer complex indicated the presence of a thermally stable and electroactive polymers. Moreover, the use of water-soluble templates, used as well as dopants, provided a unique combination of properties such as high electronic conductivity, and processability. These polymers/copolymers are nowadays tested/evaluated for antirust features on airplanes and helicopters. However, other electronic applications, such as photovoltaics, for transparent conductive polyaniline, actuators, for polypyrrole, and antistatic films, for polyEDOT, will be proposed.

  12. Biochemical synthesis of water soluble conducting polymers

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, Ferdinando F., E-mail: Ferdinando-Bruno@uml.edu [US Army Natick Soldier Research, Development and Engineering Center, Natick, MA 01760 (United States); Bernabei, Manuele [ITAF, Test Flight Centre, Chemistry Dept. Pratica di Mare AFB, 00071 Pomezia (Rome), Italy (UE) (Italy)

    2016-05-18

    An efficient biomimetic route for the synthesis of conducting polymers/copolymers complexed with lignin sulfonate and sodium (polystyrenesulfonate) (SPS) will be presented. This polyelectrolyte assisted PEG-hematin or horseradish peroxidase catalyzed polymerization of pyrrole (PYR), 3,4 ethyldioxithiophene (EDOT) and aniline has provided a route to synthesize water-soluble conducting polymers/copolymers under acidic conditions. The UV-vis, FTIR, conductivity and cyclic voltammetry studies for the polymers/copolymer complex indicated the presence of a thermally stable and electroactive polymers. Moreover, the use of water-soluble templates, used as well as dopants, provided a unique combination of properties such as high electronic conductivity, and processability. These polymers/copolymers are nowadays tested/evaluated for antirust features on airplanes and helicopters. However, other electronic applications, such as photovoltaics, for transparent conductive polyaniline, actuators, for polypyrrole, and antistatic films, for polyEDOT, will be proposed.

  13. Biochemical synthesis of water soluble conducting polymers

    International Nuclear Information System (INIS)

    Bruno, Ferdinando F.; Bernabei, Manuele

    2016-01-01

    An efficient biomimetic route for the synthesis of conducting polymers/copolymers complexed with lignin sulfonate and sodium (polystyrenesulfonate) (SPS) will be presented. This polyelectrolyte assisted PEG-hematin or horseradish peroxidase catalyzed polymerization of pyrrole (PYR), 3,4 ethyldioxithiophene (EDOT) and aniline has provided a route to synthesize water-soluble conducting polymers/copolymers under acidic conditions. The UV-vis, FTIR, conductivity and cyclic voltammetry studies for the polymers/copolymer complex indicated the presence of a thermally stable and electroactive polymers. Moreover, the use of water-soluble templates, used as well as dopants, provided a unique combination of properties such as high electronic conductivity, and processability. These polymers/copolymers are nowadays tested/evaluated for antirust features on airplanes and helicopters. However, other electronic applications, such as photovoltaics, for transparent conductive polyaniline, actuators, for polypyrrole, and antistatic films, for polyEDOT, will be proposed.

  14. Soluble organic nanotubes for catalytic systems

    Science.gov (United States)

    Xiong, Linfeng; Yang, Kunran; Zhang, Hui; Liao, Xiaojuan; Huang, Kun

    2016-03-01

    In this paper, we report a novel method for constructing a soluble organic nanotube supported catalyst system based on single-molecule templating of core-shell bottlebrush copolymers. Various organic or metal catalysts, such as sodium prop-2-yne-1-sulfonate (SPS), 1-(2-(prop-2-yn-1-yloxy)ethyl)-1H-imidazole (PEI) and Pd(OAc)2 were anchored onto the tube walls to functionalize the organic nanotubes via copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. Depending on the ‘confined effect’ and the accessible cavity microenvironments of tubular structures, the organic nanotube catalysts showed high catalytic efficiency and site-isolation features. We believe that the soluble organic nanotubes will be very useful for the development of high performance catalyst systems due to their high stability of support, facile functionalization and attractive textural properties.

  15. Soluble organic nanotubes for catalytic systems.

    Science.gov (United States)

    Xiong, Linfeng; Yang, Kunran; Zhang, Hui; Liao, Xiaojuan; Huang, Kun

    2016-03-18

    In this paper, we report a novel method for constructing a soluble organic nanotube supported catalyst system based on single-molecule templating of core–shell bottlebrush copolymers. Various organic or metal catalysts, such as sodium prop-2-yne-1-sulfonate (SPS), 1-(2-(prop-2-yn-1-yloxy)ethyl)-1H-imidazole (PEI) and Pd(OAc)2 were anchored onto the tube walls to functionalize the organic nanotubes via copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. Depending on the 'confined effect' and the accessible cavity microenvironments of tubular structures, the organic nanotube catalysts showed high catalytic efficiency and site-isolation features. We believe that the soluble organic nanotubes will be very useful for the development of high performance catalyst systems due to their high stability of support, facile functionalization and attractive textural properties.

  16. Peptide-targeted polymer cancerostatics

    Czech Academy of Sciences Publication Activity Database

    Böhmová, Eliška; Pola, Robert

    2016-01-01

    Roč. 65, Suppl. 2 (2016), S153-S164 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : HPMA copolymers * tumor targeting * peptides Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.461, year: 2016 http://www.biomed.cas.cz/physiolres/pdf/65%20Suppl%202/65_S153.pdf

  17. Photosystem Inspired Peptide Hybrid Catalysts

    Science.gov (United States)

    2017-06-07

    materials defined at the molecular level. We propose a novel way to make hybrid catalyst composed of inorganic nanomaterials and peptides. The...Distribution approved for public release. AF Office Of Scientific Research (AFOSR)/ IOA Arlington, Virginia 22203 Air Force Research Laboratory Air...ORGANIZATION NAME(S) AND ADDRESS(ES) SEOUL NATIONAL UNIVERSITY SNUR&DB FOUNDATION RESEARCH PARK CENTER SEOUL, 151742 KR 8. PERFORMING ORGANIZATION REPORT

  18. Peptide stabilized amphotericin B nanodisks

    Science.gov (United States)

    Tufteland, Megan; Pesavento, Joseph B.; Bermingham, Rachelle L.; Hoeprich, Paul D.; Ryan, Robert O.

    2007-01-01

    Nanometer scale apolipoprotein A-I stabilized phospholipid disk complexes (nanodisks; ND) have been formulated with the polyene antibiotic amphotericin B (AMB). The present studies were designed to evaluate if a peptide can substitute for the function of the apolipoprotein component of ND with respect to particle formation and stability. An 18-residue synthetic amphipathic α-helical peptide, termed 4F (Ac-D-W-F-K-A-F-Y-D-K-V-A-E-K-F-K-E-A-F-NH2), solubilized vesicles comprised of egg phosphatidylcholine (egg PC), dipentadecanoyl PC or dimyristoylphosphatidylcholine (DMPC) at rates greater than or equal to solubilization rates observed with human apolipoprotein A-I (apoA-I; 243 amino acids). Characterization studies revealed that interaction with DMPC induced a near doubling of 4F tryptophan fluorescence emission quantum yield (excitation 280 nm) and a ~7 nm blue shift in emission wavelength maximum. Inclusion of AMB in the vesicle substrate resulted in formation of 4F AMB-ND. Spectra of AMB containing particles revealed the antibiotic is a highly effective quencher of 4F tryptophan fluorescence emission, giving rise to a Ksv = 7.7 × 104. Negative stain electron microscopy revealed that AMB-ND prepared with 4F possessed a disk shaped morphology similar to ND prepared without AMB or prepared with apoA-I. In yeast and pathogenic fungi growth inhibition assays, 4F AMB-ND was as effective as apoA-I AMB-ND. The data indicate that AMB-ND generated using an amphipathic peptide in lieu of apoA-I form a discrete population of particles that possess potent biological activity. Given their intrinsic versatility, peptides may be preferred for scale up and clinical application of AMB-ND. PMID:17293004

  19. Hydrogen solubility measurements of analyzed tall oil fractions and a solubility model

    International Nuclear Information System (INIS)

    Uusi-Kyyny, Petri; Pakkanen, Minna; Linnekoski, Juha; Alopaeus, Ville

    2017-01-01

    Highlights: • Hydrogen solubility was measured in four tall oil fractions between 373 and 597 K. • Continuous flow synthetic isothermal and isobaric method was used. • A Henry’s law model was developed for the distilled tall oil fractions. • The complex composition of the samples was analyzed and is presented. - Abstract: Knowledge of hydrogen solubility in tall oil fractions is important for designing hydrotreatment processes of these complex nonedible biobased materials. Unfortunately measurements of hydrogen solubility into these fractions are missing in the literature. This work reports hydrogen solubility measured in four tall oil fractions between 373 and 597 K and at pressures from 5 to 10 MPa. Three of the fractions were distilled tall oil fractions their resin acids contents are respectively 2, 20 and 23 in mass-%. Additionally one fraction was a crude tall oil (CTO) sample containing sterols as the main neutral fraction. Measurements were performed using a continuous flow synthetic isothermal and isobaric method based on the visual observation of the bubble point. Composition of the flow was changed step-wise for the bubble point composition determination. We assume that the tall oil fractions did not react during measurements, based on the composition analysis performed before and after the measurements. Additionally the densities of the fractions were measured at atmospheric pressure from 293.15 to 323.15 K. A Henry’s law model was developed for the distilled tall oil fractions describing the solubility with an absolute average deviation of 2.1%. Inputs of the solubility model are temperature, total pressure and the density of the oil at 323.15 K. The solubility of hydrogen in the CTO sample can be described with the developed model with an absolute average deviation of 3.4%. The solubility of hydrogen increases both with increasing pressure and/or increasing temperature. The more dense fractions of the tall oil exhibit lower hydrogen

  20. Solubility and Permeability Studies of Aceclofenac in Different Oils

    African Journals Online (AJOL)

    The solubility and permeability of aceclofenac were compared with the hydroalcoholic solution of ... the use of lipid based systems such as micro- or .... carriers/vehicles for enhanced solubility and permeability ... modifications: A recent review.

  1. Soluble L-selectin levels predict survival in sepsis

    DEFF Research Database (Denmark)

    Seidelin, Jakob B; Nielsen, Ole H; Strøm, Jens

    2002-01-01

    To evaluate serum soluble L-selectin as a prognostic factor for survival in patients with sepsis.......To evaluate serum soluble L-selectin as a prognostic factor for survival in patients with sepsis....

  2. Soluble polymer conjugates for drug delivery.

    Science.gov (United States)

    Minko, Tamara

    2005-01-01

    The use of water-soluble polymeric conjugates as drug carriers offers several possible advantages. These advantages include: (1) improved drug pharmacokinetics; (2) decreased toxicity to healthy organs; (3) possible facilitation of accumulation and preferential uptake by targeted cells; (4) programmed profile of drug release. In this review, we will consider the main types of useful polymeric conjugates and their role and effectiveness as carriers in drug delivery systems.: © 2005 Elsevier Ltd . All rights reserved.

  3. Thermal degradation of organo-soluble polyimides

    Institute of Scientific and Technical Information of China (English)

    黄俐研; 史燚; 金熹高

    1999-01-01

    The thermal degradation behavior of two organo-soluble polyimides was investigated by high resolution pyrolysis-gas chromatography/mass spectrometry. The pyrolyzates of the polymers at various temperatures were identified and characterized quantitatively. The relationship between the polymer structure and pyrolyzate distribution was discussed. The kinetic parameters of the thermal degradation were calculated based on thermogravimetric measurements. Finally, the thermal degradation mechanism for the polymers was suggested.

  4. Measurement of Soluble Biomarkers by Flow Cytometry

    OpenAIRE

    Antal-Szalm?s, P?ter; Nagy, B?la; Debreceni, Ildik? Beke; Kappelmayer, J?nos

    2013-01-01

    Microparticle based flow cytometric assays for determination of the level of soluble biomarkers are widely used in several research applications and in some diagnostic setups. The major advantages of these multiplex systems are that they can measure a large number of analytes (up to 500) at the same time reducing assay time, costs and sample volume. Most of these assays are based on antigen-antibody interactions and work as traditional immunoassays, but nucleic acid alterations ? by using spe...

  5. Water Soluble Polymers for Pharmaceutical Applications

    OpenAIRE

    Veeran Gowda Kadajji; Guru V. Betageri

    2011-01-01

    Advances in polymer science have led to the development of novel drug delivery systems. Some polymers are obtained from natural resources and then chemically modified for various applications, while others are chemically synthesized and used. A large number of natural and synthetic polymers are available. In the present paper, only water soluble polymers are described. They have been explained in two categories (1) synthetic and (2) natural. Drug polymer conjugates, block copolymers, hydrogel...

  6. Solubility of plutonium and waste evaporation

    International Nuclear Information System (INIS)

    Karraker, D.G.

    1993-01-01

    Chemical processing of irradiated reactor elements at the Savannah River Site separates uranium, plutonium and fission products; fission products and process-added chemicals are mixed with an excess of NaOH and discharged as a basic slurry into large underground tanks for temporary storage. The slurry is composed of base-insoluble solids that settle to the bottom of the tank; the liquid supemate contains a mixture of base-soluble chemicals--nitrates, nitrites aluminate, sulfate, etc. To conserve space in the waste tanks, the supemate is concentrated by evaporation. As the evaporation proceeds, the solubilities of some components are exceeded, and these species crystallize from solution. Normally, these components are soluble in the hot solution discharged from the waste tank evaporator and do not crystallize until the solution cools. However, concern was aroused at West Valley over the possibility that plutonium would precipitate and accumulate in the evaporator, conceivably to the point that a nuclear accident was possible. There is also a concern at SRS from evaporation of sludge washes, which arise from washing the base-insoluble solids (open-quote sludge close-quote) with ca. 1M NaOH to reduce the Al and S0 4 -2 content. The sludge washes of necessity extract a low level of Pu from the sludge and are evaporated to reduce their volume, presenting the possibility of precipitating Pu. Measurements of the solubility of Pu in synthetic solutions of similar composition to waste supernate and sludge washes are described in this report

  7. Biopharmaceuticals: From peptide to drug

    Science.gov (United States)

    Hannappel, Margarete

    2017-08-01

    Biologics are therapeutic proteins or peptides that are produced by means of biological processes within living organisms and cells. They are highly specific molecules and play a crucial role as therapeutics for the treatment of severe and chronic diseases (e.g. cancer, rheumatoid arthritis, diabetes, autoimmune disorders). The development of new biologics and biologics-based drugs gains more and more importance in the fight against various diseases. A short overview on biotherapeutical drug development is given. Cone snails are a large group of poisonous, predatory sea snails with more than 700 species. They use a very powerful venom which rapidly inactivates and paralyzes their prey. Most bioactive venom components are small peptides (conotoxins, conopeptides) which are precisely directed towards a specific target (e.g. ion channel, receptors). Due to their small size, their precision and speed of action, naturally occurring cone snail venom peptides represent an attractive source for the identification and design of novel biological drug entities. The Jagna cone snail project is an encouraging initiative to map the ecological variety of cone snails around the island of Bohol (Philippines) and to conserve the biological information for potential future application.

  8. Coffee, hunger, and peptide YY.

    Science.gov (United States)

    Greenberg, James A; Geliebter, Allan

    2012-06-01

    There is evidence from several empirical studies suggesting that coffee may help people control body weight. Our objective was to assess the effects of caffeine, caffeinated coffee, and decaffeinated coffee, both alone and in combination with 75 g of glucose, on perceived hunger and satiety and related peptides. We conducted a placebo-controlled single-blinded randomized 4-way crossover trial. Eleven healthy male volunteers (mean age, 23.5 ± 5.7 years; mean BMI, 23.6 ± 4.2 kg/m(2)) ingested 1 of 3 test beverages (caffeine in water, caffeinated coffee, or decaffeinated coffee) or placebo (water), and 60 minutes later they ingested the glucose. Eight times during each laboratory visit, hunger and satiety were assessed by visual analog scales, and blood samples were drawn to measure 3 endogenous peptides associated with hunger and satiety: ghrelin, peptide YY (PYY), and leptin. Compared to placebo, decaffeinated coffee yielded significantly lower hunger during the whole 180-minute study period and higher plasma PYY for the first 90 minutes (p hunger or PYY. Caffeinated coffee showed a pattern between that of decaffeinated coffee and caffeine in water. These findings suggest that one or more noncaffeine ingredients in coffee may have the potential to decrease body weight. Glucose ingestion did not change the effects of the beverages. Our randomized human trial showed that decaffeinated coffee can acutely decrease hunger and increase the satiety hormone PYY.

  9. Aluminum Solubility in Complex Electrolytes - 13011

    Energy Technology Data Exchange (ETDEWEB)

    Agnew, S.F. [Columbia Energy and Environmental Services, Inc., 1806 Terminal Dr., Richland, WA 99354 (United States); Johnston, C.T. [Dept. of Crop, Soil, and Environmental Sciences, Purdue University, West Lafayette, IN 47907 (United States)

    2013-07-01

    Predicting aluminum solubility for Hanford and Savannah River waste liquids is very important for their disposition. It is a key mission goal at each Site to leach as much aluminum as practical from sludges in order to minimize the amount of vitrified high level waste. And it is correspondingly important to assure that any soluble aluminum does not precipitate during subsequent decontamination of the liquid leachates with ion exchange. This report shows a very simple and yet thermodynamic model for aluminum solubility that is consistent with a wide range of Al liquors, from simple mixtures of hydroxide and aluminate to over 300 Hanford concentrates and to a set of 19 Bayer liquors for temperatures from 20-100 deg. C. This dimer-dS{sub mix} (DDS) model incorporates an ideal entropy of mixing along with previous reports for the Al dimer, water activities, gibbsite, and bayerite thermodynamics. We expect this model will have broad application for nuclear wastes as well as the Bayer gibbsite process industry. (authors)

  10. Hydrogen adsorption on and solubility in graphites

    International Nuclear Information System (INIS)

    Kanashenko, S.L.; Wampler, W.R.

    1996-01-01

    The experimental data on adsorption and solubility of hydrogen isotopes in graphite over a wide range of temperatures and pressures are reviewed. Langmuir adsorption isotherms are proposed for the hydrogen-graphite interaction. The entropy and enthalpy of adsorption are estimated, allowing for effects of relaxation of dangling sp 2 bonds. Three kinds of traps are proposed: edge carbon atoms of interstitial loops with an adsorption enthalpy relative to H 2 gas of -4.4 eV/H 2 (unrelaxed, Trap 1), edge carbon atoms at grain surfaces with an adsorption enthalpy of -2.3 eV/H 2 (relaxed, Trap 2), and basal plane adsorption sites with an enthalpy of +2.43 eV/H 2 (Trap 3). The adsorption capacity of different types of graphite depends on the concentration of traps which depends on the crystalline microstructure of the material. The number of potential sites for the 'true solubility' (Trap 3) is assumed to be about one site per carbon atom in all types of graphite, but the endothermic character of this solubility leads to a negligible H inventory compared to the concentration of hydrogen in type 1 and type 2 traps for temperatures and gas pressures used in the experiments. Irradiation with neutrons or carbon atoms increases the concentration of type 1 and type 2 traps from about 20 and 200 appm respectively for unirradiated (POCO AXF-5Q) graphite to about 1500 and 5000 appm, respectively, at damage levels above 1 dpa. (orig.)

  11. Soluble Aβ aggregates can inhibit prion propagation.

    Science.gov (United States)

    Sarell, Claire J; Quarterman, Emma; Yip, Daniel C-M; Terry, Cassandra; Nicoll, Andrew J; Wadsworth, Jonathan D F; Farrow, Mark A; Walsh, Dominic M; Collinge, John

    2017-11-01

    Mammalian prions cause lethal neurodegenerative diseases such as Creutzfeldt-Jakob disease (CJD) and consist of multi-chain assemblies of misfolded cellular prion protein (PrP C ). Ligands that bind to PrP C can inhibit prion propagation and neurotoxicity. Extensive prior work established that certain soluble assemblies of the Alzheimer's disease (AD)-associated amyloid β-protein (Aβ) can tightly bind to PrP C , and that this interaction may be relevant to their toxicity in AD. Here, we investigated whether such soluble Aβ assemblies might, conversely, have an inhibitory effect on prion propagation. Using cellular models of prion infection and propagation and distinct Aβ preparations, we found that the form of Aβ assemblies which most avidly bound to PrP in vitro also inhibited prion infection and propagation. By contrast, forms of Aβ which exhibit little or no binding to PrP were unable to attenuate prion propagation. These data suggest that soluble aggregates of Aβ can compete with prions for binding to PrP C and emphasize the bidirectional nature of the interplay between Aβ and PrP C in Alzheimer's and prion diseases. Such inhibitory effects of Aβ on prion propagation may contribute to the apparent fall-off in the incidence of sporadic CJD at advanced age where cerebral Aβ deposition is common. © 2017 The Authors.

  12. Solubility of plutonium dioxide aerosols, in vitro

    International Nuclear Information System (INIS)

    Newton, G.J.; Kanapilly, G.M.

    1976-01-01

    Solubility of plutonium aerosols is an important parameter in establishing risk estimates for industrial workers who might accidentally inhale these materials and in evaluating environmental health impacts associated with Pu. In vitro solubility of industrial plutonium aerosols in a simulated lung fluid is compared to similar studies with ultrafine aerosols from laser ignition of delta phase plutonium metal and laboratory-produced spherical particles of 238 PuO 2 and 239 PuO 2 . Although relatively insoluble, industrial plutonium-mixed oxide aerosols were much more soluble than laboratory-produced plutonium dioxide particles. Chain agglomerate aerosols from laser ignition of metallic Pu indicated in vitro dissolution half-times of 10 and 50 days for activity median aerodynamic diameter (AMAD) of 0.7 and 2.3 μm, respectively. Plutonium-containing mixed oxide aerosols indicated dissolution half-times of 40 to 500 days for particles formed by industrial powder comminution and blending. Centerless grinding of fuel pellets yielded plutonium-containing aerosols with dissolution half-times of 1200 to 8000 days. All mixed oxide particles were in the size range 1.0 μm to 2.5 μm AMAD

  13. Synthetic peptide vaccines: palmitoylation of peptide antigens by a thioester bond increases immunogenicity

    DEFF Research Database (Denmark)

    Beekman, N.J.C.M.; Schaaper, W.M.M.; Tesser, G.I.

    1997-01-01

    Synthetic peptides have frequently been used to immunize animals. However, peptides less than about 20 to 30 amino acids long are poor immunogens. In general, to increase its immunogenicity, the presentation of the peptide should be improved, and molecular weight needs to be increased. Many...... or an amide bond. It was found that these S-palmitoylated peptides were much more immunogenic than N-palmitoylated peptides and at least similar to KLH-conjugated peptides with respect to appearance and magnitude of induced antibodies (canine parvovirus) or immunocastration effect (gonadotropin...

  14. Chemical Methods for Peptide and Protein Production

    Directory of Open Access Journals (Sweden)

    Istvan Toth

    2013-04-01

    Full Text Available Since the invention of solid phase synthetic methods by Merrifield in 1963, the number of research groups focusing on peptide synthesis has grown exponentially. However, the original step-by-step synthesis had limitations: the purity of the final product decreased with the number of coupling steps. After the development of Boc and Fmoc protecting groups, novel amino acid protecting groups and new techniques were introduced to provide high quality and quantity peptide products. Fragment condensation was a popular method for peptide production in the 1980s, but unfortunately the rate of racemization and reaction difficulties proved less than ideal. Kent and co-workers revolutionized peptide coupling by introducing the chemoselective reaction of unprotected peptides, called native chemical ligation. Subsequently, research has focused on the development of novel ligating techniques including the famous click reaction, ligation of peptide hydrazides, and the recently reported a-ketoacid-hydroxylamine ligations with 5-oxaproline. Several companies have been formed all over the world to prepare high quality Good Manufacturing Practice peptide products on a multi-kilogram scale. This review describes the advances in peptide chemistry including the variety of synthetic peptide methods currently available and the broad application of peptides in medicinal chemistry.

  15. Chemical methods for peptide and protein production.

    Science.gov (United States)

    Chandrudu, Saranya; Simerska, Pavla; Toth, Istvan

    2013-04-12

    Since the invention of solid phase synthetic methods by Merrifield in 1963, the number of research groups focusing on peptide synthesis has grown exponentially. However, the original step-by-step synthesis had limitations: the purity of the final product decreased with the number of coupling steps. After the development of Boc and Fmoc protecting groups, novel amino acid protecting groups and new techniques were introduced to provide high quality and quantity peptide products. Fragment condensation was a popular method for peptide production in the 1980s, but unfortunately the rate of racemization and reaction difficulties proved less than ideal. Kent and co-workers revolutionized peptide coupling by introducing the chemoselective reaction of unprotected peptides, called native chemical ligation. Subsequently, research has focused on the development of novel ligating techniques including the famous click reaction, ligation of peptide hydrazides, and the recently reported α-ketoacid-hydroxylamine ligations with 5-oxaproline. Several companies have been formed all over the world to prepare high quality Good Manufacturing Practice peptide products on a multi-kilogram scale. This review describes the advances in peptide chemistry including the variety of synthetic peptide methods currently available and the broad application of peptides in medicinal chemistry.

  16. Human Antimicrobial Peptides and Proteins

    Directory of Open Access Journals (Sweden)

    Guangshun Wang

    2014-05-01

    Full Text Available As the key components of innate immunity, human host defense antimicrobial peptides and proteins (AMPs play a critical role in warding off invading microbial pathogens. In addition, AMPs can possess other biological functions such as apoptosis, wound healing, and immune modulation. This article provides an overview on the identification, activity, 3D structure, and mechanism of action of human AMPs selected from the antimicrobial peptide database. Over 100 such peptides have been identified from a variety of tissues and epithelial surfaces, including skin, eyes, ears, mouths, gut, immune, nervous and urinary systems. These peptides vary from 10 to 150 amino acids with a net charge between −3 and +20 and a hydrophobic content below 60%. The sequence diversity enables human AMPs to adopt various 3D structures and to attack pathogens by different mechanisms. While α-defensin HD-6 can self-assemble on the bacterial surface into nanonets to entangle bacteria, both HNP-1 and β-defensin hBD-3 are able to block cell wall biosynthesis by binding to lipid II. Lysozyme is well-characterized to cleave bacterial cell wall polysaccharides but can also kill bacteria by a non-catalytic mechanism. The two hydrophobic domains in the long amphipathic α-helix of human cathelicidin LL-37 lays the basis for binding and disrupting the curved anionic bacterial membrane surfaces by forming pores or via the carpet model. Furthermore, dermcidin may serve as ion channel by forming a long helix-bundle structure. In addition, the C-type lectin RegIIIα can initially recognize bacterial peptidoglycans followed by pore formation in the membrane. Finally, histatin 5 and GAPDH(2-32 can enter microbial cells to exert their effects. It appears that granulysin enters cells and kills intracellular pathogens with the aid of pore-forming perforin. This arsenal of human defense proteins not only keeps us healthy but also inspires the development of a new generation of personalized

  17. Solubility of Meloxicam in Mixed Solvent Systems | Babu | Ethiopian ...

    African Journals Online (AJOL)

    The solubility of meloxicam is higher in phosphate buffer (pH 7.4) compared to water, probably due to ionization of the drug. The solubility of meloxicam is marginally enhanced in surfactant systems (Tween 80 and Brij 35) at concentrations higher than cmc, proving the micellar solubilization. Meloxicam solubility studies in ...

  18. The Hildebrand Solubility Parameters of Ionic Liquids—Part 2

    Science.gov (United States)

    Marciniak, Andrzej

    2011-01-01

    The Hildebrand solubility parameters have been calculated for eight ionic liquids. Retention data from the inverse gas chromatography measurements of the activity coefficients at infinite dilution were used for the calculation. From the solubility parameters, the enthalpies of vaporization of ionic liquids were estimated. Results are compared with solubility parameters estimated by different methods. PMID:21747694

  19. The Hildebrand solubility parameters of ionic liquids-part 2.

    Science.gov (United States)

    Marciniak, Andrzej

    2011-01-01

    The Hildebrand solubility parameters have been calculated for eight ionic liquids. Retention data from the inverse gas chromatography measurements of the activity coefficients at infinite dilution were used for the calculation. From the solubility parameters, the enthalpies of vaporization of ionic liquids were estimated. Results are compared with solubility parameters estimated by different methods.

  20. The Hildebrand Solubility Parameters of Ionic Liquids—Part 2

    Directory of Open Access Journals (Sweden)

    Andrzej Marciniak

    2011-06-01

    Full Text Available The Hildebrand solubility parameters have been calculated for eight ionic liquids. Retention data from the inverse gas chromatography measurements of the activity coefficients at infinite dilution were used for the calculation. From the solubility parameters, the enthalpies of vaporization of ionic liquids were estimated. Results are compared with solubility parameters estimated by different methods.

  1. Aqueous solubility, dispersibility and toxicity of biodiesels

    International Nuclear Information System (INIS)

    Hollebone, B.P.; Fieldhouse, B.; Lumley, T.C.; Landriault, M.; Doe, K.; Jackman, P.

    2007-01-01

    The renewed interest in the use of biological fuels can be attributed to that fact that feedstocks for fatty-acid ester biodiesels are renewable and can be reclaimed from waste. Although there are significant benefits to using biodiesels, their increased use leaves potential for accidental release to the environment. Therefore, their environmental behaviours and impacts must be evaluated along with the risk associated with their use. Biodiesel fuels may be made from soy oil, canola oil, reclaimed restaurant grease, fish oil and animal fat. The toxicological fate of biofuel depends on the variability of its chemical composition. This study provided an initial assessment of the aqueous fate and effects of biodiesel from a broad range of commonly available feedstocks and their blends with petroleum diesels. The study focused primarily on the fate and impact of these fuels in fresh-water. The use of chemical dispersion as a countermeasure for saltwater was also investigated. The exposure of aquatic ecosystems to biodiesels and petroleum diesel occurs via the transfer of material from the non-aqueous phase liquid (NAPL) into the aqueous phase, as both soluble and dispersed components. The aqueous solubilities of the fuels were determined from the equilibrium water-accommodated fraction concentrations. The acute toxicities of many biodiesels were reported for 3 test species used by Environment Canada for toxicological evaluation, namely rainbow trout, the water flea and a luminescent bacterium. This study also evaluated the natural potential for dispersion of the fuels in the water column in both low and high-energy wave conditions. Chemical dispersion as a potential countermeasure for biodiesel spills was also evaluated using solubility testing, acute toxicity testing, and dispersibility testing. It was shown that biodiesels have much different fates and impacts from petroleum diesels. The compounds partitioning into the water column are also very different for each

  2. Self-assembly of cationic multidomain peptide hydrogels: supramolecular nanostructure and rheological properties dictate antimicrobial activity

    Science.gov (United States)

    Jiang, Linhai; Xu, Dawei; Sellati, Timothy J.; Dong, He

    2015-11-01

    Hydrogels are an important class of biomaterials that have been widely utilized for a variety of biomedical/medical applications. The biological performance of hydrogels, particularly those used as wound dressing could be greatly advanced if imbued with inherent antimicrobial activity capable of staving off colonization of the wound site by opportunistic bacterial pathogens. Possessing such antimicrobial properties would also protect the hydrogel itself from being adversely affected by microbial attachment to its surface. We have previously demonstrated the broad-spectrum antimicrobial activity of supramolecular assemblies of cationic multi-domain peptides (MDPs) in solution. Here, we extend the 1-D soluble supramolecular assembly to 3-D hydrogels to investigate the effect of the supramolecular nanostructure and its rheological properties on the antimicrobial activity of self-assembled hydrogels. Among designed MDPs, the bactericidal activity of peptide hydrogels was found to follow an opposite trend to that in solution. Improved antimicrobial activity of self-assembled peptide hydrogels is dictated by the combined effect of supramolecular surface chemistry and storage modulus of the bulk materials, rather than the ability of individual peptides/peptide assemblies to penetrate bacterial cell membrane as observed in solution. The structure-property-activity relationship developed through this study will provide important guidelines for designing biocompatible peptide hydrogels with built-in antimicrobial activity for various biomedical applications.Hydrogels are an important class of biomaterials that have been widely utilized for a variety of biomedical/medical applications. The biological performance of hydrogels, particularly those used as wound dressing could be greatly advanced if imbued with inherent antimicrobial activity capable of staving off colonization of the wound site by opportunistic bacterial pathogens. Possessing such antimicrobial properties would

  3. Cellular and soluble components decrease the viable pathogen counts in milk from dairy cows with subclinical mastitis.

    Science.gov (United States)

    Koshiishi, Tomoko; Watanabe, Masako; Miyake, Hajime; Hisaeda, Keiichi; Isobe, Naoki

    2017-08-10

    The present study was undertaken to clarify the factors that reduce the viable pathogen count in milk collected from the udders of subclinical mastitic cows during preservation. Milk was centrifuged to divide somatic cells (cellular components, precipitates) and antimicrobial peptides (soluble components, supernatants without fat layer); each fraction was cultured with bacteria, and the number of viable bacteria was assessed prior to and after culture. In 28.8% of milk samples, we noted no viable bacteria immediately after collection; this value increased significantly after a 5-hr incubation of milk with cellular components but not with soluble components (48.1 and 28.8%, respectively). After culture with cellular components, the numbers of bacteria (excluding Staphylococcus aureus and Streptococcus uberis) and yeast decreased dramatically, although the differences were not statistically significant. After cultivation with soluble components, only yeasts showed a tendency toward decreased mean viability, whereas the mean bacterial counts of S. uberis and T. pyogenes tended to increase after 5-hr preservation with soluble components. These results suggest that most pathogens in high somatic cell count (SCC) milk decreased during preservation at 15 to 25°C, due to both the cellular components and antimicrobial components in the milk. Particularly, the cellular components more potently reduced bacterial counts during preservation.

  4. Effect of composition of simulated intestinal media on the solubility of poorly soluble compounds investigated by design of experiments

    DEFF Research Database (Denmark)

    Madsen, Cecilie Maria; Feng, Kung-I; Leithead, Andrew

    2018-01-01

    The composition of the human intestinal fluids varies both intra- and inter-individually. This will influence the solubility of orally administered drug compounds, and hence, the absorption and efficacy of compounds displaying solubility limited absorption. The purpose of this study was to assess...... studies feasible compared to single SIF solubility studies. Applying this DoE approach will lead to a better understanding of the impact of intestinal fluid composition on the solubility of a given drug compound....

  5. Phosphorylated peptides occur in a non-helical portion of the tail of a catch muscle myosin

    International Nuclear Information System (INIS)

    Castellani, L.; Elliott, B.W. Jr.; Cohen, C.

    1987-01-01

    Myosin from a molluscan catch muscle (the Anterior Byssus Retractor (ABRM) of Mytilus edulis) is unusual in being phosphorylated in the rod by an endogenous heavy-chain kinase. This phosphorylation enhances myosin solubility at low ionic strength and induces molecular folding of the myosin tail. Papain and chymotryptic cleavage of this myosin, phosphorylated with [γ- 32 P]ATP, indicates that the phosphorylated residues are associated with the carboxy-terminal end of the light meromyosin. Ion-exchange and reverse-phase HPLC of radiolabeled chymotryptic peptides allow the isolation of two different peptides with high specific activity. One of these peptides is rich in lysine and arginine residues, a finding consistent with the observation that basic residues often determine the substrate specificity of protein kinases. The second peptide contains proline residues. Taken together, these results suggest that, as in the case of Acanthamoeba myosin, phosphorylation occurs in a nonhelical portion of the rod that may also control solubility. Identification of the residues that are phosphorylated and their location in the rod may reveal how the phosphorylation-dependent changes observed in the myosin in vitro are related to changes in intermolecular interactions in the thick filaments in vivo

  6. Oral formulation strategies to improve solubility of poorly water-soluble drugs.

    Science.gov (United States)

    Singh, Abhishek; Worku, Zelalem Ayenew; Van den Mooter, Guy

    2011-10-01

    In the past two decades, there has been a spiraling increase in the complexity and specificity of drug-receptor targets. It is possible to design drugs for these diverse targets with advances in combinatorial chemistry and high throughput screening. Unfortunately, but not entirely unexpectedly, these advances have been accompanied by an increase in the structural complexity and a decrease in the solubility of the active pharmaceutical ingredient. Therefore, the importance of formulation strategies to improve the solubility of poorly water-soluble drugs is inevitable, thus making it crucial to understand and explore the recent trends. Drug delivery systems (DDS), such as solid dispersions, soluble complexes, self-emulsifying drug delivery systems (SEDDS), nanocrystals and mesoporous inorganic carriers, are discussed briefly in this review, along with examples of marketed products. This article provides the reader with a concise overview of currently relevant formulation strategies and proposes anticipated future trends. Today, the pharmaceutical industry has at its disposal a series of reliable and scalable formulation strategies for poorly soluble drugs. However, due to a lack of understanding of the basic physical chemistry behind these strategies, formulation development is still driven by trial and error.

  7. Synthesis of peptide .alpha.-thioesters

    Science.gov (United States)

    Camarero, Julio A [Livermore, CA; Mitchell, Alexander R [Livermore, CA; De Yoreo, James J [Clayton, CA

    2008-08-19

    Disclosed herein is a new method for the solid phase peptide synthesis (SPPS) of C-terminal peptide .alpha. thioesters using Fmoc/t-Bu chemistry. This method is based on the use of an aryl hydrazine linker, which is totally stable to conditions required for Fmoc-SPPS. When the peptide synthesis has been completed, activation of the linker is achieved by mild oxidation. The oxidation step converts the acyl-hydrazine group into a highly reactive acyl-diazene intermediate which reacts with an .alpha.-amino acid alkylthioester (H-AA-SR) to yield the corresponding peptide .alpha.-thioester in good yield. A variety of peptide thioesters, cyclic peptides and a fully functional Src homology 3 (SH3) protein domain have been successfully prepared.

  8. Peptide YY receptors in the brain

    International Nuclear Information System (INIS)

    Inui, A.; Oya, M.; Okita, M.

    1988-01-01

    Radiolabelled ligand binding studies demonstrated that specific receptors for peptide YY are present in the porcine as well as the canine brains. Peptide YY was bound to brain tissue membranes via high-affinity (dissociation constant, 1.39 X 10(-10)M) and low-affinity (dissociation constant, 3.72 X 10(-8)M) components. The binding sites showed a high specificity for peptide YY and neuropeptide Y, but not for pancreatic polypeptide or structurally unrelated peptides. The specific activity of peptide YY binding was highest in the hippocampus, followed by the pituitary gland, the hypothalamus, and the amygdala of the porcine brain, this pattern being similarly observed in the canine brain. The results suggest that peptide YY and neuropeptide Y may regulate the function of these regions of the brain through interaction with a common receptor site

  9. The human endolymphatic sac expresses natriuretic peptides

    DEFF Research Database (Denmark)

    Møller, Martin Nue; Kirkeby, Svend; Vikeså, Jonas

    2017-01-01

    : Several natriuretic peptides were found expressed significantly in the ES, including uroguanylin and brain natriuretic peptide, but also peptides regulating vascular tone, including adrenomedullin 2. In addition, both neurophysin and oxytocin (OXT) were found significantly expressed. All peptides were...... verified by immunohistochemistry. CONCLUSION: The present data support the hypothesis that the human ES may have an endocrine/paracrine capacity through expression of several peptides with potent natriuretic activity. Furthermore, the ES may influence the hypothalamo-pituitary-adrenal axis and may regulate...... vasopressin receptors and aquaporin-2 channels in the inner ear via OXT expression. We hypothesize that the ES is likely to regulate inner ear endolymphatic homeostasis, possibly through secretion of several peptides, but it may also influence systemic and/or intracranial blood pressure through direct...

  10. Potent peptidic fusion inhibitors of influenza virus

    Energy Technology Data Exchange (ETDEWEB)

    Kadam, Rameshwar U.; Juraszek, Jarek; Brandenburg, Boerries; Buyck, Christophe; Schepens, Wim B. G.; Kesteleyn, Bart; Stoops, Bart; Vreeken, Rob J.; Vermond, Jan; Goutier, Wouter; Tang, Chan; Vogels, Ronald; Friesen, Robert H. E.; Goudsmit, Jaap; van Dongen, Maria J. P.; Wilson, Ian A.

    2017-09-28

    Influenza therapeutics with new targets and mechanisms of action are urgently needed to combat potential pandemics, emerging viruses, and constantly mutating strains in circulation. We report here on the design and structural characterization of potent peptidic inhibitors of influenza hemagglutinin. The peptide design was based on complementarity-determining region loops of human broadly neutralizing antibodies against the hemagglutinin (FI6v3 and CR9114). The optimized peptides exhibit nanomolar affinity and neutralization against influenza A group 1 viruses, including the 2009 H1N1 pandemic and avian H5N1 strains. The peptide inhibitors bind to the highly conserved stem epitope and block the low pH–induced conformational rearrangements associated with membrane fusion. These peptidic compounds and their advantageous biological properties should accelerate the development of new small molecule– and peptide-based therapeutics against influenza virus.

  11. Designing anticancer peptides by constructive machine learning.

    Science.gov (United States)

    Grisoni, Francesca; Neuhaus, Claudia; Gabernet, Gisela; Müller, Alex; Hiss, Jan; Schneider, Gisbert

    2018-04-21

    Constructive machine learning enables the automated generation of novel chemical structures without the need for explicit molecular design rules. This study presents the experimental application of such a generative model to design membranolytic anticancer peptides (ACPs) de novo. A recurrent neural network with long short-term memory cells was trained on alpha-helical cationic amphipathic peptide sequences and then fine-tuned with 26 known ACPs. This optimized model was used to generate unique and novel amino acid sequences. Twelve of the peptides were synthesized and tested for their activity on MCF7 human breast adenocarcinoma cells and selectivity against human erythrocytes. Ten of these peptides were active against cancer cells. Six of the active peptides killed MCF7 cancer cells without affecting human erythrocytes with at least threefold selectivity. These results advocate constructive machine learning for the automated design of peptides with desired biological activities. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Production of a water-soluble fertilizer containing amino acids by solid-state fermentation of soybean meal and evaluation of its efficacy on the rapeseed growth.

    Science.gov (United States)

    Wang, Jianlei; Liu, Zhemin; Wang, Yue; Cheng, Wen; Mou, Haijin

    2014-10-10

    Soybean meal is a by-product of soybean oil extraction and contains approximately 44% protein. We performed solid-state fermentation by using Bacillus subtilis strain N-2 to produce a water-soluble fertilizer containing amino acids. Strain N-2 produced a high yield of protease, which transformed the proteins in soybean meal into peptide and free amino acids that were dissolved in the fermentation products. Based on the Plackett-Burman design, the initial pH of the fermentation substrate, number of days of fermentation, and the ratio of liquid to soybean meal exhibited significant effects on the recovery of proteins in the resulting water-soluble solution. According to the predicted results of the central composite design, the highest recovery of soluble proteins (99.072%) was achieved at the optimum conditions. Under these conditions, the resulting solution contained 50.42% small peptides and 7.9% poly-γ-glutamic acid (γ-PGA). The water-soluble fertilizer robustly increased the activity of the rapeseed root system, chlorophyll content, leaf area, shoot dry weight, root length, and root weight at a concentration of 0.25% (w/v). This methodology offers a value-added use of soybean meal. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Determination of antioxidant activity of bioactive peptide fractions obtained from yogurt.

    Science.gov (United States)

    Aloğlu, H Sanlıdere; Oner, Z

    2011-11-01

    In this study, physicochemical and microbiological properties of traditional and commercial yogurt samples were determined during 4 wk of storage. Proteolytic activity, which occurs during the storage period of yogurt samples, was also determined. Peptide fractions obtained from yogurts were investigated and the effect of proteolysis on peptide release during storage was determined. The antioxidant activities of peptides released from yogurt water-soluble extracts (WSE) and from HPLC fractions were determined by 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. The antioxidant activity of WSE from traditional yogurt was greater than that of WSE from commercial yogurts. In analysis by the ABTS method, mean values increased from 7.697 to 8.739 mM Trolox/g in commercial yogurts, and from 10.115 to 13.182 mM Trolox/g in traditional yogurts during storage. Antioxidant activities of peptides released from HPLC fractions of selected yogurt samples increased 10 to 200 times. In all yogurt samples, the greatest antioxidant activity was shown in the F2 fraction. After further fractionation of yogurt samples, the fractions coded as F2.2, F2.3, F4.3, and F4.4 had the highest antioxidant activity values. Total antioxidant activity of yogurts was low but after purification of peptides by fractionation in HPLC, peptide fractions with high antioxidant activity were obtained. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  14. The solubility-permeability interplay and its implications in formulation design and development for poorly soluble drugs.

    Science.gov (United States)

    Dahan, Arik; Miller, Jonathan M

    2012-06-01

    While each of the two key parameters of oral drug absorption, the solubility and the permeability, has been comprehensively studied separately, the relationship and interplay between the two have been largely ignored. For instance, when formulating a low-solubility drug using various solubilization techniques: what are we doing to the apparent permeability when we increase the solubility? Permeability is equal to the drug's diffusion coefficient through the membrane times the membrane/aqueous partition coefficient divided by the membrane thickness. The direct correlation between the intestinal permeability and the membrane/aqueous partitioning, which in turn is dependent on the drug's apparent solubility in the GI milieu, suggests that the solubility and the permeability are closely associated, exhibiting a certain interplay between them, and the current view of treating the one irrespectively of the other may not be sufficient. In this paper, we describe the research that has been done thus far, and present new data, to shed light on this solubility-permeability interplay. It has been shown that decreased apparent permeability accompanies the solubility increase when using different solubilization methods. Overall, the weight of the evidence indicates that the solubility-permeability interplay cannot be ignored when using solubility-enabling formulations; looking solely at the solubility enhancement that the formulation enables may be misleading with regards to predicting the resulting absorption, and hence, the solubility-permeability interplay must be taken into account to strike the optimal solubility-permeability balance, in order to maximize the overall absorption.

  15. Head-To-Head Comparison of Different Solubility-Enabling Formulations of Etoposide and Their Consequent Solubility-Permeability Interplay.

    Science.gov (United States)

    Beig, Avital; Miller, Jonathan M; Lindley, David; Carr, Robert A; Zocharski, Philip; Agbaria, Riad; Dahan, Arik

    2015-09-01

    The purpose of this study was to conduct a head-to-head comparison of different solubility-enabling formulations, and their consequent solubility-permeability interplay. The low-solubility anticancer drug etoposide was formulated in several strengths of four solubility-enabling formulations: hydroxypropyl-β-cyclodextrin, the cosolvent polyethylene glycol 400 (PEG-400), the surfactant sodium lauryl sulfate, and an amorphous solid dispersion formulation. The ability of these formulations to increase the solubility of etoposide was investigated, followed by permeability studies using the parallel artificial membrane permeability assay (PAMPA) and examination of the consequent solubility-permeability interplay. All formulations significantly increased etoposide's apparent solubility. The cyclodextrin-, surfactant-, and cosolvent-based formulations resulted in a concomitant decreased permeability that could be modeled directly from the proportional increase in the apparent solubility. On the contrary, etoposide permeability remained constant when using the ASD formulation, irrespective of the increased apparent solubility provided by the formulation. In conclusion, supersaturation resulting from the amorphous form overcomes the solubility-permeability tradeoff associated with other formulation techniques. Accounting for the solubility-permeability interplay may allow to develop better solubility-enabling formulations, thereby maximizing the overall absorption of lipophilic orally administered drugs. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  16. Use of galerina marginata genes and proteins for peptide production

    Science.gov (United States)

    Hallen-Adams, Heather E.; Scott-Craig, John S.; Walton, Jonathan D.; Luo, Hong

    2018-04-03

    The present invention relates to compositions and methods comprising genes and peptides associated with cyclic peptides and cyclic peptide production in mushrooms. In particular, the present invention relates to using genes and proteins from Galerina species encoding peptides specifically relating to amatoxins in addition to proteins involved with processing cyclic peptide toxins. In a preferred embodiment, the present invention also relates to methods for making small peptides and small cyclic peptides including peptides similar to amanitin. Further, the present inventions relate to providing kits for making small peptides.

  17. Use of Galerina marginata genes and proteins for peptide production

    Energy Technology Data Exchange (ETDEWEB)

    Hallen-Adams, Heather E.; Scott-Craig, John S.; Walton, Jonathan D.; Luo, Hong

    2017-03-21

    The present invention relates to compositions and methods comprising genes and peptides associated with cyclic peptides and cyclic peptide production in mushrooms. In particular, the present invention relates to using genes and proteins from Galerina species encoding peptides specifically relating to amatoxins in addition to proteins involved with processing cyclic peptide toxins. In a preferred embodiment, the present invention also relates to methods for making small peptides and small cyclic peptides including peptides similar to amanitin. Further, the present inventions relate to providing kits for making small peptides.

  18. Highly selective enrichment of phosphorylated peptides from peptide mixtures using titanium dioxide microcolumns

    DEFF Research Database (Denmark)

    Larsen, Martin Røssel; Thingholm, Tine E; Jensen, Ole N

    2005-01-01

    based on TiO2microcolumns and peptide loading in 2,5-dihydroxybenzoic acid (DHB). The effect of DHB was a very efficient reduction in the binding of nonphosphorylated peptides to TiO2 while retaining its high binding affinity for phosphorylated peptides. Thus, inclusion of DHB dramatically increased...... the selectivity of the enrichment of phosphorylated peptides by TiO2. We demonstrated that this new procedure was more selective for binding phosphorylated peptides than IMAC using MALDI mass spectrometry. In addition, we showed that LC-ESI-MSMS was biased toward monophosphorylated peptides, whereas MALDI MS...... was not. Other substituted aromatic carboxylic acids were also capable of specifically reducing binding of nonphosphorylated peptides, whereas phosphoric acid reduced binding of both phosphorylated and nonphosphorylated peptides. A putative mechanism for this intriguing effect is presented....

  19. Production of peptide antisera specific for mouse and rat proinsulin C-peptide 2

    DEFF Research Database (Denmark)

    Blume, N; Madsen, O D; Kofod, Hans

    1990-01-01

    for antibody binding to the immunizing antigen. Antisera to C-peptide 2, stained islet beta-cells on mouse and rat, but not monkey pancreas sections in immunocytochemical analysis. Preabsorption to the synthetic C-peptide 2, but not the synthetic mouse and rat C-peptide 1 abolished staining. In conclusion we......Mice and rats have two functional non-allelic insulin genes. By using a synthetic peptide representing a common sequence in mouse and rat C-peptide 2 as antigen, we have produced rabbit antisera specific for an epitope which is not present in mouse or rat C-peptide 1. Long-term immunization did...... not seem to increase the end point titre as tested in direct ELISA. The specificity of the antiserum was determined by competitive ELISA and histochemistry on pancreas sections. Only the synthetic C-peptide 2, but not the homologous synthetic C-peptide 1 from mouse and rat competed efficiently in ELISA...

  20. Therapeutic peptides for cancer therapy. Part I - peptide inhibitors of signal transduction cascades.

    Science.gov (United States)

    Bidwell, Gene L; Raucher, Drazen

    2009-10-01

    Therapeutic peptides have great potential as anticancer agents owing to their ease of rational design and target specificity. However, their utility in vivo is limited by low stability and poor tumor penetration. The authors review the development of peptide inhibitors with potential for cancer therapy. Peptides that inhibit signal transduction cascades are discussed. The authors searched Medline for articles concerning the development of therapeutic peptides and their delivery. Given our current knowledge of protein sequences, structures and interaction interfaces, therapeutic peptides that inhibit interactions of interest are easily designed. These peptides are advantageous because they are highly specific for the interaction of interest, and they are much more easily developed than small molecule inhibitors of the same interactions. The main hurdle to application of peptides for cancer therapy is their poor pharmacokinetic and biodistribution parameters. Therefore, successful development of peptide delivery vectors could potentially make possible the use of this new and very promising class of anticancer agents.

  1. β-Klotho as a Negative Regulator of the Peptide Transporters PEPT1 and PEPT2

    Directory of Open Access Journals (Sweden)

    Abeer Abousaab

    2016-12-01

    Full Text Available Background/Aims: β-Klotho, a transmembrane protein expressed in several tissues including the brain and the kidney, is critically important for inhibition of 1,25(OH2D3 formation by FGF23. The extracellular domain of Klotho protein could be cleaved off, thus being released into blood or cerebrospinal fluid. Soluble klotho is a β-glucuronidase participating in the regulation of several ion channels and carriers. The present study explored the effect of β-Klotho protein on the peptide transporters PEPT1 and PEPT2. Methods: cRNA encoding PEPT1 or PEPT2 was injected into Xenopus laevis oocytes and glycine-glycine (2 mM-induced inward current (IGly taken as measure of glycine-glycine transport. Measurements were made without or with prior 24 h treatment with soluble β-Klotho protein (30 ng/ml in the absence and presence of β-glucuronidase inhibitor D-saccharic acid 1,4-lactone monohydrate (DSAL,10 µM. Ussing chamber experiments were employed to determine electrogenic peptide transport across intestinal epithelia of klotho deficient (kl-/- and corresponding wild type (kl+/+ mice. Results: IGly was observed in PEPT1 and in PEPT2 expressing oocytes but not in water injected oocytes. In both, PEPT1 and PEPT2 expressing oocytes IGly was significantly decreased by treatment with soluble β-Klotho protein. As shown for PEPT1, β-klotho protein decreased significantly the maximal transport rate without significantly modifying the affinity of the carrier. The effect of β-Klotho on PEPT1 was reversed by DSAL. Intestinal IGly was significantly larger in kl-/- than in kl+/+ mice. Conclusion: β-Klotho participates in the regulation of the peptide transporters PEPT1 and PEPT2.

  2. A novel chimeric peptide with antimicrobial activity.

    Science.gov (United States)

    Alaybeyoglu, Begum; Akbulut, Berna Sariyar; Ozkirimli, Elif

    2015-04-01

    Beta-lactamase-mediated bacterial drug resistance exacerbates the prognosis of infectious diseases, which are sometimes treated with co-administration of beta-lactam type antibiotics and beta-lactamase inhibitors. Antimicrobial peptides are promising broad-spectrum alternatives to conventional antibiotics in this era of evolving bacterial resistance. Peptides based on the Ala46-Tyr51 beta-hairpin loop of beta-lactamase inhibitory protein (BLIP) have been previously shown to inhibit beta-lactamase. Here, our goal was to modify this peptide for improved beta-lactamase inhibition and cellular uptake. Motivated by the cell-penetrating pVEC sequence, which includes a hydrophobic stretch at its N-terminus, our approach involved the addition of LLIIL residues to the inhibitory peptide N-terminus to facilitate uptake. Activity measurements of the peptide based on the 45-53 loop of BLIP for enhanced inhibition verified that the peptide was a competitive beta-lactamase inhibitor with a K(i) value of 58 μM. Incubation of beta-lactam-resistant cells with peptide decreased the number of viable cells, while it had no effect on beta-lactamase-free cells, indicating that this peptide had antimicrobial activity via beta-lactamase inhibition. To elucidate the molecular mechanism by which this peptide moves across the membrane, steered molecular dynamics simulations were carried out. We propose that addition of hydrophobic residues to the N-terminus of the peptide affords a promising strategy in the design of novel antimicrobial peptides not only against beta-lactamase but also for other intracellular targets. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd.

  3. Estimation of aqueous solubility of TODGA using group contribution method

    International Nuclear Information System (INIS)

    Balasubramonian, S.; Kumar, Shekhar; Sampath, M.; Sivakumar, D.; Kamachi Mudali, U.

    2017-01-01

    The aqueous solubility of N, N, N', N'-tetraoctyl-3-oxapentanediamide normally referred as TODGA is experimentally measured. The aqueous solubility was also predicted using Marrero and Gani group contribution method. The modification of original Marrero and Gani method was proposed to accurately predict TODGA solubility. The predicted solubility of TODGA using original Marrero and Gani method, Modified Marrero and Gani method and UNIFAC Model was compared. The predicted solubility of TODGA using modified Marrero and Gani method is 0.0237 g/l against the experimentally measured value of 0.0226 g/l. (author)

  4. Study of solubility of some metal cyclohexane carbonates

    International Nuclear Information System (INIS)

    Niyazov, A.N.; Amanov, K.B.; Trapeznikova, V.F.; Kul'maksimov, A.; Kolosova, N.

    1978-01-01

    The solubility of calcium, magnesium, strontium, barium, cabalt, copper and aluminium cyclohexane, carbonates (CHC) in water has been studied at 25 deg C. The salt solubility has been calculated according to the metal ion concentration in saturated solutions. It has been established, that the cobalt and rare earth cyclohexane carbonates are relatively very soluble in water and have solubility products of SP > 1x10 -5 . The solubility of CHC of multivalent metals increases with the decrease of pH values. Each salt has some ''limiting'' pH value of a solution, below which it decomposes completely and can not exist in a solution in the form of solid phase

  5. Peptide Drug Release Behavior from Biodegradable Temperature-Responsive Injectable Hydrogels Exhibiting Irreversible Gelation

    Directory of Open Access Journals (Sweden)

    Kazuyuki Takata

    2017-10-01

    Full Text Available We investigated the release behavior of glucagon-like peptide-1 (GLP-1 from a biodegradable injectable polymer (IP hydrogel. This hydrogel shows temperature-responsive irreversible gelation due to the covalent bond formation through a thiol-ene reaction. In vitro sustained release of GLP-1 from an irreversible IP formulation (F(P1/D+PA40 was observed compared with a reversible (physical gelation IP formulation (F(P1. Moreover, pharmaceutically active levels of GLP-1 were maintained in blood after subcutaneous injection of the irreversible IP formulation into rats. This system should be useful for the minimally invasive sustained drug release of peptide drugs and other water-soluble bioactive reagents.

  6. Applications of hydrophilic interaction chromatography to amino acids, peptides, and proteins.

    Science.gov (United States)

    Periat, Aurélie; Krull, Ira S; Guillarme, Davy

    2015-02-01

    This review summarizes the recent advances in the analysis of amino acids, peptides, and proteins using hydrophilic interaction chromatography. Various reports demonstrate the successful analysis of amino acids under such conditions. However, a baseline resolution of the 20 natural amino acids has not yet been published and for this reason, there is often a need to use mass spectrometry for detection to further improve selectivity. Hydrophilic interaction chromatography is also recognized as a powerful technique for peptide analysis, and there are a lot of papers showing its applicability for proteomic applications (peptide mapping). It is expected that its use for peptide mapping will continue to grow in the future, particularly because this analytical strategy can be combined with reversed-phase liquid chromatography, in a two-dimensional setup, to reach very high resolving power. Finally, the interest in hydrophilic interaction chromatography for intact proteins analysis is less evident due to possible solubility issues and a lack of suitable hydrophilic interaction chromatography stationary phases. To date, it has been successfully employed only for the characterization of membrane proteins, histones, and the separation of glycosylated isoforms of an intact glycoprotein. From our point of view, the number of hydrophilic interaction chromatography columns compatible with intact proteins (higher upper temperature limit, large pore size, etc.) is still too limited. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. The role of metals in protein conformational disorders - The case of prion protein and Aβ -peptide

    International Nuclear Information System (INIS)

    De Santis, E; Minicozzi, V; Morante, S; Rossi, G C; Stellato, F

    2016-01-01

    Protein conformational disorders are members of a vast class of pathologies in which endogenous proteins or peptides undergo a misfolding process by switching from the physiological soluble configuration to a pathological fibrillar insoluble state. An important, but not yet fully elucidated, role in the process appears to be played by transition metal ions, mainly copper and zinc. X-ray absorption spectroscopy is one of the most suitable techniques for the structural characterization of biological molecules in complex with metal. Owing to its chemical selectivity and sensitivity to the local atomic geometry around the absorber, it can be successfully used to study the environment of metal ions in complex with proteins and peptides in physiological conditions. In this paper we present X-ray absorption spectroscopy studies of the metal ions coordination modes in systems where metals are complexed with specific amyloidogenic proteins and peptides. In particular, we show results concerning the Amyloid β peptide, that is involved in Alzheimer's disease, and the Prion protein, that is responsible for the Transmissible Spongiform Encephalopathy. Our findings suggest that the copper and zinc ions may play a crucial role in the aggregation and fibril formation process of these two biomolecules. Elucidating this kind of interaction could be a key preliminary step before any viable therapy can be conceived or designed. (paper)

  8. The role of metals in protein conformational disorders - The case of prion protein and Aβ -peptide

    Science.gov (United States)

    De Santis, E.; Minicozzi, V.; Morante, S.; Rossi, G. C.; Stellato, F.

    2016-02-01

    Protein conformational disorders are members of a vast class of pathologies in which endogenous proteins or peptides undergo a misfolding process by switching from the physiological soluble configuration to a pathological fibrillar insoluble state. An important, but not yet fully elucidated, role in the process appears to be played by transition metal ions, mainly copper and zinc. X-ray absorption spectroscopy is one of the most suitable techniques for the structural characterization of biological molecules in complex with metal. Owing to its chemical selectivity and sensitivity to the local atomic geometry around the absorber, it can be successfully used to study the environment of metal ions in complex with proteins and peptides in physiological conditions. In this paper we present X-ray absorption spectroscopy studies of the metal ions coordination modes in systems where metals are complexed with specific amyloidogenic proteins and peptides. In particular, we show results concerning the Amyloid β peptide, that is involved in Alzheimer's disease, and the Prion protein, that is responsible for the Transmissible Spongiform Encephalopathy. Our findings suggest that the copper and zinc ions may play a crucial role in the aggregation and fibril formation process of these two biomolecules. Elucidating this kind of interaction could be a key preliminary step before any viable therapy can be conceived or designed.

  9. Distinct thermodynamic signatures of oligomer generation in the aggregation of the amyloid-β peptide

    Science.gov (United States)

    Cohen, Samuel I. A.; Cukalevski, Risto; Michaels, Thomas C. T.; Šarić, Andela; Törnquist, Mattias; Vendruscolo, Michele; Dobson, Christopher M.; Buell, Alexander K.; Knowles, Tuomas P. J.; Linse, Sara

    2018-05-01

    Mapping free-energy landscapes has proved to be a powerful tool for studying reaction mechanisms. Many complex biomolecular assembly processes, however, have remained challenging to access using this approach, including the aggregation of peptides and proteins into amyloid fibrils implicated in a range of disorders. Here, we generalize the strategy used to probe free-energy landscapes in protein folding to determine the activation energies and entropies that characterize each of the molecular steps in the aggregation of the amyloid-β peptide (Aβ42), which is associated with Alzheimer's disease. Our results reveal that interactions between monomeric Aβ42 and amyloid fibrils during fibril-dependent secondary nucleation fundamentally reverse the thermodynamic signature of this process relative to primary nucleation, even though both processes generate aggregates from soluble peptides. By mapping the energetic and entropic contributions along the reaction trajectories, we show that the catalytic efficiency of Aβ42 fibril surfaces results from the enthalpic stabilization of adsorbing peptides in conformations amenable to nucleation, resulting in a dramatic lowering of the activation energy for nucleation.

  10. Micelles from lipid derivatives of water-soluble polymers as delivery systems for poorly soluble drugs.

    Science.gov (United States)

    Lukyanov, Anatoly N; Torchilin, Vladimir P

    2004-05-07

    Polymeric micelles have a whole set of unique characteristics, which make them very promising drug carriers, in particular, for poorly soluble drugs. Our review article focuses on micelles prepared from conjugates of water-soluble polymers, such as polyethylene glycol (PEG) or polyvinyl pyrrolidone (PVP), with phospholipids or long-chain fatty acids. The preparation of micelles from certain polymer-lipid conjugates and the loading of these micelles with various poorly soluble anticancer agents are discussed. The data on the characterization of micellar preparations in terms of their morphology, stability, longevity in circulation, and ability to spontaneously accumulate in experimental tumors via the enhanced permeability and retention (EPR) effect are presented. The review also considers the preparation of targeted immunomicelles with specific antibodies attached to their surface. Available in vivo results on the efficiency of anticancer drugs incorporated into plain micelles and immunomicelles in animal models are also discussed.

  11. Overcoming the solubility limit with solubility-enhancement tags: successful applications in biomolecular NMR studies

    International Nuclear Information System (INIS)

    Zhou Pei; Wagner, Gerhard

    2010-01-01

    Although the rapid progress of NMR technology has significantly expanded the range of NMR-trackable systems, preparation of NMR-suitable samples that are highly soluble and stable remains a bottleneck for studies of many biological systems. The application of solubility-enhancement tags (SETs) has been highly effective in overcoming solubility and sample stability issues and has enabled structural studies of important biological systems previously deemed unapproachable by solution NMR techniques. In this review, we provide a brief survey of the development and successful applications of the SET strategy in biomolecular NMR. We also comment on the criteria for choosing optimal SETs, such as for differently charged target proteins, and recent new developments on NMR-invisible SETs.

  12. Antimicrobial Peptides, Infections and the Skin Barrier

    DEFF Research Database (Denmark)

    Clausen, Maja Lisa; Agner, Tove

    2016-01-01

    The skin serves as a strong barrier protecting us from invading pathogens and harmful organisms. An important part of this barrier comes from antimicrobial peptides (AMPs), which are small peptides expressed abundantly in the skin. AMPs are produced in the deeper layers of the epidermis and trans......The skin serves as a strong barrier protecting us from invading pathogens and harmful organisms. An important part of this barrier comes from antimicrobial peptides (AMPs), which are small peptides expressed abundantly in the skin. AMPs are produced in the deeper layers of the epidermis...

  13. Development and characterization of nanoparticulate formulation of a water soluble prodrug of dexamethasone by HIP complexation.

    Science.gov (United States)

    Gaudana, Ripal; Parenky, Ashwin; Vaishya, Ravi; Samanta, Swapan K; Mitra, Ashim K

    2011-01-01

    The objective of this study was to develop and characterize a nanoparticulate-based sustained release formulation of a water soluble dipeptide prodrug of dexamethasone, valine-valine-dexamethasone (VVD). Being hydrophilic in nature, it readily leaches out in the external aqueous medium and hence partitions poorly into the polymeric matrix resulting in minimal entrapment in nanoparticles. Hence, hydrophobic ion pairing (HIP) complexation of the prodrug was employed with dextran sulphate as a complexing polymer. A novel, solid in oil in water emulsion method was employed to encapsulate the prodrug in HIP complex form in poly(lactic-co-glycolic acid) matrix. Nanoparticles were characterized with respect to size, zeta potential, crystallinity of entrapped drug and surface morphology. A significant enhancement in the entrapment of the prodrug in nanoparticles was achieved. Finally, a simple yet novel method was developed which can also be applicable to encapsulate other charged hydrophilic molecules, such as peptides and proteins.

  14. Formation of zinc-peptide spherical microparticles during lyophilization from tert-butyl alcohol/water co-solvent system.

    Science.gov (United States)

    Qian, Feng; Ni, Nina; Chen, Jia-Wen; Desikan, Sridhar; Naringrekar, Vijay; Hussain, Munir A; Barbour, Nancy P; Smith, Ronald L

    2008-12-01

    phase ("dispersed TBA hydrate"). Decreasing the temperature further causes the formation of a eutectic mixture between TBA hydrate ("eutectic TBA hydrate") and water. Due to its low aqueous solubility, the zinc peptide adduct accumulates in both of the dispersed and eutectic TBA hydrate phases to form a hydrophobic "oil" phase. Since the eutectic TBA hydrate phase is surrounded by ice, a "solid emulsion" forms to lower the interfacial energy, and gives rise to spherical zinc peptide particles upon solvent sublimation. Possibility of liquid-liquid phase separation during freeze-drying was also investigated, and no evidence was found to support this alternative mechanism.

  15. Pyridyl-alanine as a Hydrophilic, Aromatic Element in Peptide Structural Optimization.

    Science.gov (United States)

    Mroz, Piotr A; Perez-Tilve, Diego; Liu, Fa; Gelfanov, Vasily; DiMarchi, Richard D; Mayer, John P

    2016-09-08

    Glucagon (Gcg) 1 serves a seminal physiological role in buffering against hypoglycemia, but its poor biophysical properties severely complicate its medicinal use. We report a series of novel glucagon analogues of enhanced aqueous solubility and stability at neutral pH, anchored by Gcg[Aib16]. Incorporation of 3- and 4-pyridyl-alanine (3-Pal and 4-Pal) enhanced aqueous solubility of glucagon while maintaining biological properties. Relative to native hormone, analogue 9 (Gcg[3-Pal6,10,13, Aib16]) demonstrated superior biophysical character, better suitability for medicinal purposes, and comparable pharmacology against insulin-induced hypoglycemia in rats and pigs. Our data indicate that Pal is a versatile surrogate to natural aromatic amino acids and can be employed as an alternative or supplement with isoelectric adjustment to refine the biophysical character of peptide drug candidates.

  16. Diagnosing solubility limitations – the example of hydrate formation

    Directory of Open Access Journals (Sweden)

    Joerg Berghausen

    2014-07-01

    Full Text Available Solubility is regarded as one of the key challenges in many drug discovery projects. Thus, it’s essential to support the lead finding and optimization efforts by appropriate solubility data. In silico solubility prediction remains challenging and therefore a screening assay is used as a first filter, followed by selected follow-up assays to reveal what causes the low solubility of a specific compound or chemotype. Results from diagnosing the underlying reason for solubility limitation are discussed. As lipophilicity and crystal lattice forces are regarded as main contributors to limiting solubility, changes in solid state are important to be recognized. Solubility limitation by various factors will be presented and the impact of the solid-state is exemplified by compounds that are able to form hydrates.

  17. Characterization of Soluble Organics in Produced Water

    Energy Technology Data Exchange (ETDEWEB)

    Bostick, D.T.

    2002-01-16

    Soluble organics in produced water and refinery effluents represent treatment problems for the petroleum industry. Neither the chemistry involved in the production of soluble organics nor the impact of these chemicals on total effluent toxicity is well understood. The U.S. Department of Energy provides funding for Oak Ridge National Laboratory (ORNL) to support a collaborative project with Shell, Chevron, Phillips, and Statoil entitled ''Petroleum and Environmental Research Forum project (PERF 9844: Manage Water-Soluble Organics in Produced Water''). The goal of this project, which involves characterization and evaluation of these water-soluble compounds, is aimed at reducing the future production of such contaminants. To determine the effect that various drilling conditions might have on water-soluble organics (WSO) content in produced water, a simulated brine water containing the principal inorganic components normally found in Gulf of Mexico (GOM) brine sources was prepared. The GOM simulant was then contacted with as-received crude oil from a deep well site to study the effects of water cut, produced-water pH, salinity, pressure, temperature, and crude oil sources on the type and content of the WSO in produced water. The identities of individual semivolatile organic compounds (SVOCs) were determined in all as-received crude and actual produced water samples using standard USEPA Method (8270C) protocol. These analyses were supplemented with the more general measurements of total petroleum hydrocarbon (TPH) content in the gas (C{sub 6}-C{sub 10}), diesel (C{sub 10}-C{sub 20}), and oil (C{sub 20}-C{sub 28}) carbon ranges as determined by both gas chromatographic (GC) and infrared (IR) analyses. An open liquid chromatographic procedure was also used to differentiate the saturated hydrocarbon, aromatic hydrocarbon, and polar components within the extractable TPH. Inorganic constituents in the produced water were analyzed by ion

  18. Effect of glycosylation on biodistribution of radiolabeled glucagon-like peptide 1

    International Nuclear Information System (INIS)

    Watanabe, Ayahisa; Nishijima, Ken-ichi; Zhao, Songji; Tamaki, Nagara; Kuge, Yuji; Tanaka, Yoshikazu; Itoh, Takeshi; Takemoto, Hiroshi

    2012-01-01

    Glycosylation is generally applicable as a strategy for increasing the activity of bioactive proteins. In this study, we examined the effect of glycosylation on biodistribution of radiolabeled glucagon-like peptide 1 (GLP-1) as a bioactive peptide for type 2 diabetes. Noninvasive imaging studies were performed using a gamma camera after the intravenous administration of 123 I-GLP-1 or 123 I-α2, 6-sialyl N-acetyllactosamine (glycosylated) GLP-1 in rats. In ex vivo biodistribution studies using 125 I-GLP-1 or 125 I-glycosylated GLP-1, organ samples were measured for radioactivity. Plasma samples were added to 15% trichloroacetic acid (TCA) to obtain TCA-insoluble and TCA-soluble fractions. The radioactivity in the TCA-insoluble and TCA-soluble fractions was measured. In the noninvasive imaging studies, a relatively high accumulation level of 123 I-GLP-1 was found in the liver, which is the major organ to eliminate exogenous GLP-1. The area under the time-activity curve (AUC) of 123 I-glycosylated GLP-1 in the liver was significantly lower (89%) than that of 123 I-GLP-1. These results were consistent with those of ex vivo biodistribution studies using 125 I-labeled peptides. The AUC of 125 I-glycosylated GLP-1 in the TCA-insoluble fraction was significantly higher (1.7-fold) than that of GLP-1. This study demonstrated that glycosylation significantly decreased the distribution of radiolabeled GLP-1 into the liver and increased the concentration of radiolabeled GLP-1 in plasma. These results suggested that glycosylation is a useful strategy for decreasing the distribution into the liver of bioactive peptides as desirable pharmaceuticals. (author)

  19. Novel electrosprayed nanospherules for enhanced aqueous solubility and oral bioavailability of poorly water-soluble fenofibrate

    Directory of Open Access Journals (Sweden)

    Yousaf AM

    2016-01-01

    Full Text Available Abid Mehmood Yousaf,1,2 Omer Mustapha,1 Dong Wuk Kim,1 Dong Shik Kim,1 Kyeong Soo Kim,1 Sung Giu Jin,1 Chul Soon Yong,3 Yu Seok Youn,4 Yu-Kyoung Oh,5 Jong Oh Kim,3 Han-Gon Choi1 1College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Gyeonggi, South Korea; 2Faculty of Pharmacy, University of Central Punjab, Johar, Lahore, Pakistan; 3College of Pharmacy, Yeungnam University, Gyongsan, North Gyeongsang, 4School of Pharmacy, Sungkyunkwan University, Suwon, Gyeonggi, 5College of Pharmacy, Seoul National University, Seoul, South Korea Purpose: The purpose of the present research was to develop a novel electrosprayed nanospherule providing the most optimized aqueous solubility and oral bioavailability for poorly water-soluble fenofibrate.Methods: Numerous fenofibrate-loaded electrosprayed nanospherules were prepared with polyvinylpyrrolidone (PVP and Labrafil® M 2125 as carriers using the electrospray technique, and the effect of the carriers on drug solubility and solvation was assessed. The solid state characterization of an optimized formulation was conducted by scanning electron microscopy, powder X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopic analyses. Oral bioavailability in rats was also evaluated for the formulation of an optimized nanospherule in comparison with free drug and a conventional fenofibrate-loaded solid dispersion.Results: All of the electrosprayed nanospherule formulations had remarkably enhanced aqueous solubility and dissolution compared with free drug. Moreover, Labrafil M 2125, a surfactant, had a positive influence on the solubility and dissolution of the drug in the electrosprayed nanospherule. Increases were observed as the PVP/drug ratio increased to 4:1, but higher ratios gave no significant increases. In particular, an electrosprayed nanospherule composed of fenofibrate, PVP, and Labrafil M 2125 at the weight ratio of 1

  20. Antioxidant activity of yoghurt peptides: Part 2 – Characterisationof peptide fractions

    DEFF Research Database (Denmark)

    Farvin, Sabeena; Baron, Caroline; Nielsen, Nina Skall

    2010-01-01

    the peptides identified contained at least one proline residue. Some of the identified peptides included the hydrophobic amino acid residues Val or Leu at the N-terminus and Pro, His or Tyr in the amino acid sequence, which is characteristic of antioxidant peptides. In addition, the yoghurt contained...

  1. Connecting peptide (c-peptide) and the duration of diabetes mellitus ...

    African Journals Online (AJOL)

    Objective: C-peptide is derived from proinsulin and it is secreted in equimolar concentration with insulin. Plasma C-peptide is more stable than insulin and it provides an indirect measure of insulin secretory reserve and beta cell function. To determine relationship between C-peptide and duration of diabetes mellitus, age, ...

  2. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to “αS1-casein tryptic hydrolysate” and alleviation of psychological stress (ID 656, 1819, 4253) pursuant to Article 13(1) of Regulation (EC) No 1924/2006

    DEFF Research Database (Denmark)

    Tetens, Inge

    claims in relation to “αS1-casein tryptic hydrolysate” and alleviation of psychological stress. The scientific substantiation is based on the information provided by the Member States in the consolidated list of Article 13 health claims and references that EFSA has received from Member States or directly......Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies was asked to provide a scientific opinion on a list of health claims pursuant to Article 13 of Regulation (EC) No 1924/2006. This opinion addresses the scientific substantiation of health...... that alleviation of psychological stress might be a beneficial physiological effect. No references were provided from which conclusions could be drawn for the scientific substantiation of the claim. On the basis of the data presented, the Panel concludes that a cause and effect relationship has not been...

  3. Radiometallating antibodies and autoantigenic peptides

    International Nuclear Information System (INIS)

    Mercer-Smith, J.A.; Lewis, D.; Cole, D.A.; Newmyer, S.L.; Schulte, L.D.; Mixon, P.L.; Schreyer, S.A.; Burns, T.P.; Roberts, J.C.; Figard, S.D.; McCormick, D.J.; Lennon, V.A.; Hayashi, M.; Lavallee, D.K.

    1991-01-01

    We have developed methods to radiolabel large molecules, using porphyrins as bifunctional chelating agents for radiometals. The porphyrins are substituted with an N- benzyl group to activate them for radiometallation under mild reaction conditions. Porphyrins that have one functional group for covalent attachment to other molecules cannot cause crosslinking. We have examined the labeling chemistry for antibodies and have developed methods to label smaller biologically active molecules, such as autoantigenic peptides (fragments of the acetylcholine receptor), which are pertinent to myasthenia gravis research. The methods of covalent attachment of these bifunctional chelating agents to large molecules, the radiometallation chemistry, and biological characterization of the radiolabeled compounds will be discussed

  4. Atrial natriuretic peptides in plasma

    DEFF Research Database (Denmark)

    Goetze, Jens Peter; Hansen, Lasse H; Terzic, Dijana

    2014-01-01

    Measurement of cardiac natriuretic peptides in plasma has gained a diagnostic role in the assessment of heart failure. Plasma measurement is though hampered by the marked instability of the hormones, which has led to the development of analyses that target N-terminal fragments from the prohormone....... These fragments are stable in plasma and represent surrogate markers of the actual natriuretic hormone. Post-translational processing of the precursors, however, is revealing itself to be a complex event with new information still being reported on proteolysis, covalent modifications, and amino acid...

  5. Atrial natriuretic peptides in plasma

    DEFF Research Database (Denmark)

    Goetze, Jens P; Holst Hansen, Lasse; Terzic, Dijana

    2015-01-01

    Measurement of cardiac natriuretic peptides in plasma has gained a diagnostic role in the assessment of heart failure. Plasma measurement is though hampered by the marked instability of the hormones, which has led to the development of analyses that target N-terminal fragments from the prohormone....... These fragments are stable in plasma and represent surrogate markers of the actual natriuretic hormone. Post-translational processing of the precursors, however, is revealing itself to be a complex event with new information still being reported on proteolysis, covalent modifications, and amino acid...

  6. Synthesis of radioiodinated labeled peptides

    International Nuclear Information System (INIS)

    Matloobi, M.; Rafii, H.; Beigi, D.; Khalaj, A.; Kamali-Dehghan, M.

    2003-01-01

    Optimization of radioiodination of peptides is covered by both a direct method in which a constituent tyrosine residue is labeled and indirect method by using an iodinated derivative (SIB) of N succinimidyl 3-(tri-n-butylstannyl) benzoate (ATE) as the intermediate. Radioiodination of IgG and FMLF were performed by direct method using Chloramine-T as an oxidant but since Formyl-Methyl-Leucyl-Phenylalanine, FMLF, does not lend itself for direct radioiodination we performed labeling of FMLF by indirect method via radioiodined SIB at different pH. (author)

  7. Radioimmunological determination of soluble immune complexes

    Energy Technology Data Exchange (ETDEWEB)

    Falck, P; Meffert, H; Diezel, W; Schmidt, E; Soennichsen, N [Humboldt-Universitaet, Berlin (German Democratic Republic). Bereich Medizin (Charite)

    1979-04-01

    Soluble immune complexes were determined in sera from patients with systemic lupus erythematosus, using /sup 125/I-labelled anti-Ig-antibody and plastics-fixed C1q (component of complement). The detection limit of the method is 0.1 ..mu..g of aggregated human IgG and the range is between 0.1 ..mu..g and 10 ..mu..g per 0.5 ml serum. In 58% of the sera tested an increase of the number of immune complexes was found.

  8. Effect of a Fusion Peptide by Covalent Conjugation of a Mitochondrial Cell-Penetrating Peptide and a Glutathione Analog Peptide

    Directory of Open Access Journals (Sweden)

    Carmine Pasquale Cerrato

    2017-06-01

    Full Text Available Previously, we designed and synthesized a library of mitochondrial antioxidative cell-penetrating peptides (mtCPPs superior to the parent peptide, SS31, to protect mitochondria from oxidative damage. A library of antioxidative glutathione analogs called glutathione peptides (UPFs, exceptional in hydroxyl radical elimination compared with glutathione, were also designed and synthesized. Here, a follow-up study is described, investigating the effects of the most promising members from both libraries on reactive oxidative species scavenging ability. None of the peptides influenced cell viability at the concentrations used. Fluorescence microscopy studies showed that the fluorescein-mtCPP1-UPF25 (mtgCPP internalized into cells, and spectrofluorometric analysis determined the presence and extent of peptide into different cell compartments. mtgCPP has superior antioxidative activity compared with mtCPP1 and UPF25 against H2O2 insult, preventing ROS formation by 2- and 3-fold, respectively. Moreover, we neither observed effects on mitochondrial membrane potential nor production of ATP. These data indicate that mtgCPP is targeting mitochondria, protecting them from oxidative damage, while also being present in the cytosol. Our hypothesis is based on a synergistic effect resulting from the fused peptide. The mitochondrial peptide segment is targeting mitochondria, whereas the glutathione analog peptide segment is active in the cytosol, resulting in increased scavenging ability.

  9. peptide

    Indian Academy of Sciences (India)

    Prakash

    effects can be observed under certain conditions but these are not always .... of proteins with amyloid characteristics in muscle (Jayaraman et al. 2008) ... not enhance the growth of dangerous fibrils generated at pH. 7.4. ..... The lower chart shows Aβ(25-35) aggregation kinetics during the first 4 min of monitoring. Results are ...

  10. Peptide hormones and lung cancer.

    Science.gov (United States)

    Moody, T W

    2006-03-01

    Several peptide hormones have been identified which alter the proliferation of lung cancer. Small cell lung cancer (SCLC), which is a neuroendocrine cancer, produces and secretes gastrin releasing peptide (GRP), neurotensin (NT) and adrenomedullin (AM) as autocrine growth factors. GRP, NT and AM bind to G-protein coupled receptors causing phosphatidylinositol turnover or elevated cAMP in SCLC cells. Addition of GRP, NT or AM to SCLC cells causes altered expression of nuclear oncogenes, such as c-fos, and stimulation of growth. Antagonists have been developed for GRP, NT and AM receptors which function as cytostatic agents and inhibit SCLC growth. Growth factor antagonists, such as the NT1 receptor antagonist SR48692, facilitate the ability of chemotherapeutic drugs to kill lung cancer cells. It remains to be determined if GRP, NT and AM receptors will served as molecular targets, for development of new therapies for the treatment of SCLC patients. Non-small cell lung cancer (NSCLC) cells also have a high density of GRP, NT, AM and epidermal growth factor (EGF) receptors. Several NSCLC patients with EGF receptor mutations respond to gefitinib, a tyrosine kinase inhibitor. Gefitinib relieves NSCLC symptoms, maintaining stable disease in patients who are not eligible for systemic chemotherapy. It is important to develop new therapeutic approaches using translational research techniques for the treatment of lung cancer patients.

  11. Synthetic mimics of antimicrobial peptides.

    Science.gov (United States)

    Som, Abhigyan; Vemparala, Satyavani; Ivanov, Ivaylo; Tew, Gregory N

    2008-01-01

    Infectious diseases and antibiotic resistance are now considered the most imperative global healthcare problem. In the search for new treatments, host defense, or antimicrobial, peptides have attracted considerable attention due to their various unique properties; however, attempts to develop in vivo therapies have been severely limited. Efforts to develop synthetic mimics of antimicrobial peptides (SMAMPs) have increased significantly in the last decade, and this review will focus primarily on the structural evolution of SMAMPs and their membrane activity. This review will attempt to make a bridge between the design of SMAMPs and the fundamentals of SMAMP-membrane interactions. In discussions regarding the membrane interaction of SMAMPs, close attention will be paid to the lipid composition of the bilayer. Despite many years of study, the exact conformational aspects responsible for the high selectivity of these AMPs and SMAMPs toward bacterial cells over mammalian cells are still not fully understood. The ability to design SMAMPs that are potently antimicrobial, yet nontoxic to mammalian cells has been demonstrated with a variety of molecular scaffolds. Initial animal studies show very good tissue distribution along with more than a 4-log reduction in bacterial counts. The results on SMAMPs are not only extremely promising for novel antibiotics, but also provide an optimistic picture for the greater challenge of general proteomimetics.

  12. Solubility of xenon in liquid sodium

    International Nuclear Information System (INIS)

    Veleckis, E.; Cafasso, F.A.; Feder, H.M.

    1976-01-01

    The solubility of xenon in liquid sodium was measured as a function of pressure (2-8 atm) and temperature (350-600 0 C). Henry's law was obeyed with the value of the Henry's law constant, K/sub H/ = N/sub Xe//P, ranging from 1.38 x 10 -10 atm -1 at 350C, to 1.59 x 10 -8 atm -1 at 600 0 C where N/sub Xe/ and P are the atom fraction and the partial pressure of xenon, respectively. The temperature dependence of solubility may be represented by log 10 lambda = (0.663 +- 0.01) - (4500 +- 73) T -1 , where lambda is the Ostwald coefficient (the volume of xenon dissolved per unit volume of sodium at the temperature of the experiment). The heat of solution of xenon in sodium was 20.6 +- 0.7 kcal/mole, where the standard state of xenon is defined as that of 1 mole of an ideal gas, confined to a volume equal to the molar volume of sodium

  13. Solubility and bioavailability improvement of pazopanib hydrochloride.

    Science.gov (United States)

    Herbrink, Maikel; Groenland, Stefanie L; Huitema, Alwin D R; Schellens, Jan H M; Beijnen, Jos H; Steeghs, Neeltje; Nuijen, Bastiaan

    2018-06-10

    The anti-cancer drug pazopanib hydrochloride (PZH) has a very low aqueous solubility and a variable oral bioavailability. A new pharmaceutical formulation with an improved solubility may enhance the bioavailability and reduce the variability. A broad selection of polymer excipients was tested for their compatibility and solubilizing properties by conventional microscopic, thermal and spectrometric techniques. A wet milling and mixing technique was used to produce homogenous powder mixtures. The dissolution properties of the formulation were tested by a pH-switch dissolution model. The final formulation was tested in vivo in cancer patient following a dose escalation design. Of the tested mixture formulations, the one containing the co-block polymer Soluplus® in a 8:1 ratio with PZH performed best in terms of in vitro dissolution properties. The in vivo results indicated that 300 mg of the developed formulation yields similar exposure and a lower variability (379 μg/mL∗h (36.7% CV)) than previously reported values for the standard PZH formulation (Votrient®) at the approved dose of 800 mg. Furthermore, the expected plasma-C through levels (27.2 μg/mL) exceeds the defined therapeutic efficacy threshold of 20 μg/mL. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Driving engineering of novel antimicrobial peptides from simulations of peptide-micelle interactions

    DEFF Research Database (Denmark)

    Khandelia, Himanshu; Langham, Allison A; Kaznessis, Yiannis N

    2006-01-01

    Simulations of antimicrobial peptides in membrane mimics can provide the high resolution, atomistic picture that is necessary to decipher which sequence and structure components are responsible for activity and toxicity. With such detailed insight, engineering new sequences that are active but non...... peptides and their interaction with membrane mimics. In this article, we discuss the promise and the challenges of widely used models and detail our recent work on peptide-micelle simulations as an attractive alternative to peptide-bilayer simulations. We detail our results with two large structural...... classes of peptides, helical and beta-sheet and demonstrate how simulations can assist in engineering of novel antimicrobials with therapeutic potential....

  15. Enhancement of carvedilol solubility by solid dispersion technique using cyclodextrins, water soluble polymers and hydroxyl acid.

    Science.gov (United States)

    Yuvaraja, K; Khanam, Jasmina

    2014-08-05

    Aim of the present work is to enhance aqueous solubility of carvedilol (CV) by solid dispersion technique using wide variety of carriers such as: β-cyclodextrin (βCD), hydroxypropyl-β-cyclodextrin (HPβCD), tartaric acid (TA), polyvinyl pyrrolidone K-30 (PVP K-30) and poloxamer-407 (PLX-407). Various products of 'CV-solid dispersion' had been studied extensively in various pH conditions to check enhancement of solubility and dissolution characteristics of carvedilol. Any physical change upon interaction between CV and carriers was confirmed by instrumental analysis: XRD, DSC, FTIR and SEM. Negative change of Gibb's free energy and complexation constants (Kc, 75-240M(-1), for cyclodextrins and 1111-20,365M(-1), for PVP K-30 and PLX-407) were the evidence of stable nature of the binding between CV and carriers. 'Solubility enhancement factor' of ionized-CV was found high enough (340 times) with HPβCD in presence of TA. TA increases the binding efficiency of cyclodextrin and changing the pH of microenvironment in dissolution medium. In addition, ionization process was used to increase the apparent intrinsic solubility of drug. In vitro, dissolution time of CV was remarkably reduced in the solid dispersion system compared to that of pure drug. This may be attributed to increased wettability, dispersing ability and transformation of crystalline state of drug to amorphous one. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Development of solid lipid nanoparticles for enhanced solubility of poorly soluble drugs

    DEFF Research Database (Denmark)

    Potta, Sriharsha Gupta; Minemi, Sriharsha; Nukala, Ravi Kumar

    2010-01-01

    Cyclosporine (CyA) solid lipid nanoparticles were prepared by using a solvent free high pressure homogenization process. CyA was incorporated into SLNs that consisted of stearic acid, trilaurin or tripalmitin lipid solid cores in order to enhance drug solubility. The process was conducted...

  17. Enhancing the solubility and bioavailability of poorly water-soluble drugs using supercritical antisolvent (SAS) process.

    Science.gov (United States)

    Abuzar, Sharif Md; Hyun, Sang-Min; Kim, Jun-Hee; Park, Hee Jun; Kim, Min-Soo; Park, Jeong-Sook; Hwang, Sung-Joo

    2018-03-01

    Poor water solubility and poor bioavailability are problems with many pharmaceuticals. Increasing surface area by micronization is an effective strategy to overcome these problems, but conventional techniques often utilize solvents and harsh processing, which restricts their use. Newer, green technologies, such as supercritical fluid (SCF)-assisted particle formation, can produce solvent-free products under relatively mild conditions, offering many advantages over conventional methods. The antisolvent properties of the SCFs used for microparticle and nanoparticle formation have generated great interest in recent years, because the kinetics of the precipitation process and morphologies of the particles can be accurately controlled. The characteristics of the supercritical antisolvent (SAS) technique make it an ideal tool for enhancing the solubility and bioavailability of poorly water-soluble drugs. This review article focuses on SCFs and their properties, as well as the fundamentals of overcoming poorly water-soluble drug properties by micronization, crystal morphology control, and formation of composite solid dispersion nanoparticles with polymers and/or surfactants. This article also presents an overview of the main aspects of the SAS-assisted particle precipitation process, its mechanism, and parameters, as well as our own experiences, recent advances, and trends in development. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Ideal gas solubilities and solubility selectivities in a binary mixture of room-temperature ionic liquids.

    Science.gov (United States)

    Finotello, Alexia; Bara, Jason E; Narayan, Suguna; Camper, Dean; Noble, Richard D

    2008-02-28

    This study focuses on the solubility behaviors of CO2, CH4, and N2 gases in binary mixtures of imidazolium-based room-temperature ionic liquids (RTILs) using 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][Tf2N]) and 1-ethyl-3-methylimidazolium tetrafluoroborate ([C2mim][BF4]) at 40 degrees C and low pressures (approximately 1 atm). The mixtures tested were 0, 25, 50, 75, 90, 95, and 100 mol % [C2mim][BF4] in [C2mim][Tf2N]. Results show that regular solution theory (RST) can be used to describe the gas solubility and selectivity behaviors in RTIL mixtures using an average mixture solubility parameter or an average measured mixture molar volume. Interestingly, the solubility selectivity, defined as the ratio of gas mole fractions in the RTIL mixture, of CO2 with N2 or CH4 in pure [C2mim][BF4] can be enhanced by adding 5 mol % [C2mim][Tf2N].

  19. Overview of milling techniques for improving the solubility of poorly water-soluble drugs

    Directory of Open Access Journals (Sweden)

    Zhi Hui Loh

    2015-07-01

    Full Text Available Milling involves the application of mechanical energy to physically break down coarse particles to finer ones and is regarded as a “top–down” approach in the production of fine particles. Fine drug particulates are especially desired in formulations designed for parenteral, respiratory and transdermal use. Most drugs after crystallization may have to be comminuted and this physical transformation is required to various extents, often to enhance processability or solubility especially for drugs with limited aqueous solubility. The mechanisms by which milling enhances drug dissolution and solubility include alterations in the size, specific surface area and shape of the drug particles as well as milling-induced amorphization and/or structural disordering of the drug crystal (mechanochemical activation. Technology advancements in milling now enable the production of drug micro- and nano-particles on a commercial scale with relative ease. This review will provide a background on milling followed by the introduction of common milling techniques employed for the micronization and nanonization of drugs. Salient information contained in the cited examples are further extracted and summarized for ease of reference by researchers keen on employing these techniques for drug solubility and bioavailability enhancement.

  20. Dry season aerosol iron solubility in tropical northern Australia

    Directory of Open Access Journals (Sweden)

    V. H. L. Winton

    2016-10-01

    Full Text Available Marine nitrogen fixation is co-limited by the supply of iron (Fe and phosphorus in large regions of the global ocean. The deposition of soluble aerosol Fe can initiate nitrogen fixation and trigger toxic algal blooms in nitrate-poor tropical waters. We present dry season soluble Fe data from the Savannah Fires in the Early Dry Season (SAFIRED campaign in northern Australia that reflects coincident dust and biomass burning sources of soluble aerosol Fe. The mean soluble and total aerosol Fe concentrations were 40 and 500 ng m−3 respectively. Our results show that while biomass burning species may not be a direct source of soluble Fe, biomass burning may substantially enhance the solubility of mineral dust. We observed fractional Fe solubility up to 12 % in mixed aerosols. Thus, Fe in dust may be more soluble in the tropics compared to higher latitudes due to higher concentrations of biomass-burning-derived reactive organic species in the atmosphere. In addition, biomass-burning-derived particles can act as a surface for aerosol Fe to bind during atmospheric transport and subsequently be released to the ocean upon deposition. As the aerosol loading is dominated by biomass burning emissions over the tropical waters in the dry season, additions of biomass-burning-derived soluble Fe could have harmful consequences for initiating nitrogen-fixing toxic algal blooms. Future research is required to quantify biomass-burning-derived particle sources of soluble Fe over tropical waters.

  1. Peptide-tagged proteins in aqueous two-phase systems

    OpenAIRE

    Nilsson, Anna

    2002-01-01

    This thesis deals with proteins containing peptide tags for improved partitioning in aqueous two-phase systems. Qualitatively the peptide-tagged protein partitioning could be predicted from peptide data, i.e. partitioning trends found for peptides were also found for the peptide-tagged proteins. However, full effect of the tag as expected from peptide partitioning was not found in the tagged protein. When alkyl-ethylene oxide surfactant was included in a two-polymer system, almost full effect...

  2. Topical Peptide Treatments with Effective Anti-Aging Results

    OpenAIRE

    Silke Karin Schagen

    2017-01-01

    In the last two decades, many new peptides have been developed, and new knowledge on how peptides improve the skin has been uncovered. The spectrum of peptides in the field of cosmetics is continuously growing. This review summarizes some of the effective data on cosmeceutical peptides that work against intrinsic and extrinsic aging. Some peptides have been proven in their efficacy through clinical skin trials. Well-known and documented peptides like copper tripeptide are still under research...

  3. Prediction of twin-arginine signal peptides

    DEFF Research Database (Denmark)

    Bendtsen, Jannick Dyrløv; Nielsen, Henrik; Widdick, D.

    2005-01-01

    expressions, whereas hydrophobicity discrimination of Tat- and Sec- signal peptides is carried out by an artificial neural network. A potential cleavage site of the predicted Tat signal peptide is also reported. The TatP prediction server is available as a public web server at http://www.cbs.dtu.dk/services/TatP/....

  4. Double quick, double click reversible peptide "stapling".

    Science.gov (United States)

    Grison, Claire M; Burslem, George M; Miles, Jennifer A; Pilsl, Ludwig K A; Yeo, David J; Imani, Zeynab; Warriner, Stuart L; Webb, Michael E; Wilson, Andrew J

    2017-07-01

    The development of constrained peptides for inhibition of protein-protein interactions is an emerging strategy in chemical biology and drug discovery. This manuscript introduces a versatile, rapid and reversible approach to constrain peptides in a bioactive helical conformation using BID and RNase S peptides as models. Dibromomaleimide is used to constrain BID and RNase S peptide sequence variants bearing cysteine (Cys) or homocysteine ( h Cys) amino acids spaced at i and i + 4 positions by double substitution. The constraint can be readily removed by displacement of the maleimide using excess thiol. This new constraining methodology results in enhanced α-helical conformation (BID and RNase S peptide) as demonstrated by circular dichroism and molecular dynamics simulations, resistance to proteolysis (BID) as demonstrated by trypsin proteolysis experiments and retained or enhanced potency of inhibition for Bcl-2 family protein-protein interactions (BID), or greater capability to restore the hydrolytic activity of the RNAse S protein (RNase S peptide). Finally, use of a dibromomaleimide functionalized with an alkyne permits further divergent functionalization through alkyne-azide cycloaddition chemistry on the constrained peptide with fluorescein, oligoethylene glycol or biotin groups to facilitate biophysical and cellular analyses. Hence this methodology may extend the scope and accessibility of peptide stapling.

  5. Protein identification by peptide mass fingerprinting

    DEFF Research Database (Denmark)

    Hjernø, Karin

    2007-01-01

      Peptide mass fingerprinting is an effective way of identifying, e.g., gel-separated proteins, by matching experimentally obtained peptide mass data against large databases. However, several factors are known to influence the quality of the resulting matches, such as proteins contaminating the s...

  6. Peptide Mass Fingerprinting of Egg White Proteins

    Science.gov (United States)

    Alty, Lisa T.; LaRiviere, Frederick J.

    2016-01-01

    Use of advanced mass spectrometry techniques in the undergraduate setting has burgeoned in the past decade. However, relatively few undergraduate experiments examine the proteomics tools of protein digestion, peptide accurate mass determination, and database searching, also known as peptide mass fingerprinting. In this experiment, biochemistry…

  7. Practical use of natriuretic peptide measurement

    DEFF Research Database (Denmark)

    Husby, Simon; Lind, Bent; Goetze, Jens P

    2012-01-01

    To elucidate the knowledge regarding B-type natriuretic peptide (BNP)/N-terminal proBNP (NT-proBNP) measurement among doctors using this biomarker.......To elucidate the knowledge regarding B-type natriuretic peptide (BNP)/N-terminal proBNP (NT-proBNP) measurement among doctors using this biomarker....

  8. Novel peptide-based protease inhibitors

    DEFF Research Database (Denmark)

    Roodbeen, Renée

    of novel peptide-based protease inhibitors, efforts were made towards improved methods for peptide synthesis. The coupling of Fmoc-amino acids onto N-methylated peptidyl resins was investigated. These couplings can be low yielding and the effect of the use of microwave heating combined with the coupling...

  9. Superior Antifouling Performance of a Zwitterionic Peptide Compared to an Amphiphilic, Non-Ionic Peptide.

    Science.gov (United States)

    Ye, Huijun; Wang, Libing; Huang, Renliang; Su, Rongxin; Liu, Boshi; Qi, Wei; He, Zhimin

    2015-10-14

    The aim of this study was to explore the influence of amphiphilic and zwitterionic structures on the resistance of protein adsorption to peptide self-assembled monolayers (SAMs) and gain insight into the associated antifouling mechanism. Two kinds of cysteine-terminated heptapeptides were studied. One peptide had alternating hydrophobic and hydrophilic residues with an amphiphilic sequence of CYSYSYS. The other peptide (CRERERE) was zwitterionic. Both peptides were covalently attached onto gold substrates via gold-thiol bond formation. Surface plasmon resonance analysis results showed that both peptide SAMs had ultralow or low protein adsorption amounts of 1.97-11.78 ng/cm2 in the presence of single proteins. The zwitterionic peptide showed relatively higher antifouling ability with single proteins and natural complex protein media. We performed molecular dynamics simulations to understand their respective antifouling behaviors. The results indicated that strong surface hydration of peptide SAMs contributes to fouling resistance by impeding interactions with proteins. Compared to the CYSYSYS peptide, more water molecules were predicted to form hydrogen-bonding interactions with the zwitterionic CRERERE peptide, which is in agreement with the antifouling test results. These findings reveal a clear relation between peptide structures and resistance to protein adsorption, facilitating the development of novel peptide-containing antifouling materials.

  10. Peptide ligands for targeting the extracellular domain of EGFR: Comparison between linear and cyclic peptides.

    Science.gov (United States)

    Williams, Tyrslai M; Sable, Rushikesh; Singh, Sitanshu; Vicente, Maria Graca H; Jois, Seetharama D

    2018-02-01

    Colorectal cancer (CRC) is the third most common solid internal malignancy among cancers. Early detection of cancer is key to increasing the survival rate of colorectal cancer patients. Overexpression of the EGFR protein is associated with CRC. We have designed a series of peptides that are highly specific for the extracellular domain of EGFR, based on our earlier studies on linear peptides. The previously reported linear peptide LARLLT, known to bind to EGFR, was modified with the goals of increasing its stability and its specificity toward EGFR. Peptide modifications, including D-amino acid substitution, cyclization, and chain reversal, were investigated. In addition, to facilitate labeling of the peptide with a fluorescent dye, an additional lysine residue was introduced onto the linear (KLARLLT) and cyclic peptides cyclo(KLARLLT) (Cyclo.L1). The lysine residue was also converted into an azide group in both a linear and reversed cyclic peptide sequences cyclo(K(N3)larllt) (Cyclo.L1.1) to allow for subsequent "click" conjugation. The cyclic peptides showed enhanced binding to EGFR by SPR. NMR and molecular modeling studies suggest that the peptides acquire a β-turn structure in solution. In vitro stability studies in human serum show that the cyclic peptide is more stable than the linear peptide. © 2017 John Wiley & Sons A/S.

  11. Tumor-targeting peptides from combinatorial libraries*

    Science.gov (United States)

    Liu, Ruiwu; Li, Xiaocen; Xiao, Wenwu; Lam, Kit S.

    2018-01-01

    Cancer is one of the major and leading causes of death worldwide. Two of the greatest challenges infighting cancer are early detection and effective treatments with no or minimum side effects. Widespread use of targeted therapies and molecular imaging in clinics requires high affinity, tumor-specific agents as effective targeting vehicles to deliver therapeutics and imaging probes to the primary or metastatic tumor sites. Combinatorial libraries such as phage-display and one-bead one-compound (OBOC) peptide libraries are powerful approaches in discovering tumor-targeting peptides. This review gives an overview of different combinatorial library technologies that have been used for the discovery of tumor-targeting peptides. Examples of tumor-targeting peptides identified from each combinatorial library method will be discussed. Published tumor-targeting peptide ligands and their applications will also be summarized by the combinatorial library methods and their corresponding binding receptors. PMID:27210583

  12. Development of novel ligands for peptide GPCRs.

    Science.gov (United States)

    Moran, Brian M; McKillop, Aine M; O'Harte, Finbarr Pm

    2016-12-01

    Incretin based glucagon-like peptide-1 receptor (GLP-1R) agonists which target a G-protein coupled receptor (GPCR) are currently used in the treatment of type 2 diabetes. This review focuses on GPCRs from pancreatic β-cells, including GLP-1, glucose-dependent insulinotropic polypeptide (GIP), glucagon, somatostatin, pancreatic polypeptide (PP), cholecystokinin (CCK), peptide YY (PYY), oxyntomodulin (OXM) and ghrelin receptors. In addition, fatty acids GPCRs are thought to have an increasing role in regulating peptide secretions namely short fatty acids GPCR (GPR41, GPR43), medium chain fatty acid GPCR (GPR84), long chain fatty acid GPCR (GPR40, GPR120) and cannabinoid-like GPCR (GPR55, GPR119). Several pre-clinical and clinical trials are currently ongoing in peptide GPCR based therapies, including dual and triple agonist peptides which activate two or more GPCRs simultaneously. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Circulating elastin peptides, role in vascular pathology.

    Science.gov (United States)

    Robert, L; Labat-Robert, J

    2014-12-01

    The atherosclerotic process starts with the degradation of elastic fibers. Their presence was demonstrated in the circulation as well as several of their biological properties elucidated. We described years ago a procedure to obtain large elastin peptides by organo-alkaline hydrolysis, κ-elastin. This method enabled also the preparation of specific antibodies used to determine elastin peptides, as well as anti-elastin antibodies in body fluids and tissue extracts. Elastin peptides were determined in a large number of human blood samples. Studies were carried out to explore their pharmacological properties. Similar recent studies by other laboratories confirmed our findings and arose new interest in circulating elastin peptides for their biological activities. This recent trend justified the publication of a review of the biological and pathological activities of elastin peptides demonstrated during our previous studies, subject of this article. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  14. Interpreting peptide mass spectra by VEMS

    DEFF Research Database (Denmark)

    Mathiesen, Rune; Lundsgaard, M.; Welinder, Karen G.

    2003-01-01

    the calculated and the experimental mass spectrum of the called peptide. The program package includes four accessory programs. VEMStrans creates protein databases in FASTA format from EST or cDNA sequence files. VEMSdata creates a virtual peptide database from FASTA files. VEMSdist displays the distribution......Most existing Mass Spectra (MS) analysis programs are automatic and provide limited opportunity for editing during the interpretation. Furthermore, they rely entirely on publicly available databases for interpretation. VEMS (Virtual Expert Mass Spectrometrist) is a program for interactive analysis...... of peptide MS/MS spectra imported in text file format. Peaks are annotated, the monoisotopic peaks retained, and the b-and y-ion series identified in an interactive manner. The called peptide sequence is searched against a local protein database for sequence identity and peptide mass. The report compares...

  15. Intracellular Signalling by C-Peptide

    Directory of Open Access Journals (Sweden)

    Claire E. Hills

    2008-01-01

    Full Text Available C-peptide, a cleavage product of the proinsulin molecule, has long been regarded as biologically inert, serving merely as a surrogate marker for insulin release. Recent findings demonstrate both a physiological and protective role of C-peptide when administered to individuals with type I diabetes. Data indicate that C-peptide appears to bind in nanomolar concentrations to a cell surface receptor which is most likely to be G-protein coupled. Binding of C-peptide initiates multiple cellular effects, evoking a rise in intracellular calcium, increased PI-3-kinase activity, stimulation of the Na+/K+ ATPase, increased eNOS transcription, and activation of the MAPK signalling pathway. These cell signalling effects have been studied in multiple cell types from multiple tissues. Overall these observations raise the possibility that C-peptide may serve as a potential therapeutic agent for the treatment or prevention of long-term complications associated with diabetes.

  16. Radiolabeled peptides: experimental and clinical applications

    International Nuclear Information System (INIS)

    Thakur, M.L.; Pallela, V.R.

    1998-01-01

    Radiolabeled receptor specific biomolecules hold unlimited potential in nuclear medicine. During the past few years much attention has been drawn to the development radiolabeled peptides for a variety of diagnostic applications, as well as for therapy of malignant tumors. Although only one peptide, In-111-DTPA-(D)-Phe 1 -octreotide, is available commercially for oncologic imaging, many more have been examined in humans with hematological disorders, and the early results appear to be promising. Impetus generated by these results have prompted investigators to label peptides with such radionuclides as Tc-99m, I-123, F-18, Cu-64, and Y-90. This review is intended to highlight the qualities of peptides, summarize the clinical results, and address some important issues associated with radiolabeling of highly potent peptides. While doing so, various methods of radiolabeling have been described, and their strengths and weaknesses have also been discussed. (author)

  17. Chemical reactions directed Peptide self-assembly.

    Science.gov (United States)

    Rasale, Dnyaneshwar B; Das, Apurba K

    2015-05-13

    Fabrication of self-assembled nanostructures is one of the important aspects in nanoscience and nanotechnology. The study of self-assembled soft materials remains an area of interest due to their potential applications in biomedicine. The versatile properties of soft materials can be tuned using a bottom up approach of small molecules. Peptide based self-assembly has significant impact in biology because of its unique features such as biocompatibility, straight peptide chain and the presence of different side chain functionality. These unique features explore peptides in various self-assembly process. In this review, we briefly introduce chemical reaction-mediated peptide self-assembly. Herein, we have emphasised enzymes, native chemical ligation and photochemical reactions in the exploration of peptide self-assembly.

  18. Harnessing supramolecular peptide nanotechnology in biomedical applications.

    Science.gov (United States)

    Chan, Kiat Hwa; Lee, Wei Hao; Zhuo, Shuangmu; Ni, Ming

    2017-01-01

    The harnessing of peptides in biomedical applications is a recent hot topic. This arises mainly from the general biocompatibility of peptides, as well as from the ease of tunability of peptide structure to engineer desired properties. The ease of progression from laboratory testing to clinical trials is evident from the plethora of examples available. In this review, we compare and contrast how three distinct self-assembled peptide nanostructures possess different functions. We have 1) nanofibrils in biomaterials that can interact with cells, 2) nanoparticles that can traverse the bloodstream to deliver its payload and also be bioimaged, and 3) nanotubes that can serve as cross-membrane conduits and as a template for nanowire formation. Through this review, we aim to illustrate how various peptides, in their various self-assembled nanostructures, possess great promise in a wide range of biomedical applications and what more can be expected.

  19. Amyloid–β peptides time-dependent structural modifications: AFM and voltammetric characterization

    Energy Technology Data Exchange (ETDEWEB)

    Enache, Teodor Adrian; Chiorcea-Paquim, Ana-Maria; Oliveira-Brett, Ana Maria, E-mail: brett@ci.uc.pt

    2016-07-05

    The human amyloid beta (Aβ) peptides, Aβ{sub 1-40} and Aβ{sub 1-42}, structural modifications, from soluble monomers to fully formed fibrils through intermediate structures, were investigated, and the results were compared with those obtained for the inverse Aβ{sub 40-1} and Aβ{sub 42-1}, mutant Aβ{sub 1-40}Phe{sup 10} and Aβ{sub 1-40}Nle{sup 35}, and rat Aβ{sub 1-40}Rat peptide sequences. The aggregation was followed at a slow rate, in chloride free media and room temperature, and revealed to be a sequence-structure process, dependent on the physicochemical properties of each Aβ peptide isoforms, and occurring at different rates and by different pathways. The fibrilization process was investigated by atomic force microscopy (AFM), via changes in the adsorption morphology from: (i) initially random coiled structures of ∼0.6 nm height, corresponding to the Aβ peptide monomers in random coil or in α-helix conformations, to (ii) aggregates and protofibrils of 1.5–6.0 nm height and (iii) two types of fibrils, corresponding to the Aβ peptide in a β-sheet configuration. The reactivity of the carbon electrode surface was considered. The hydrophobic surface induced rapid changes of the Aβ peptide conformations, and differences between the adsorbed fibrils, formed at the carbon surface (beaded, thin, <2.0 nm height) or in solution (long, smooth, thick, >2.0 nm height), were detected. Differential pulse voltammetry showed that, according to their primary structure, the Aβ peptides undergo oxidation in one or two steps, the first step corresponding to the tyrosine amino acids oxidation, and the second one to the histidine and methionine amino acids oxidation. The fibrilization process was electrochemically detected via the decrease of the Aβ peptide oxidation peak currents that occurred in a time dependent manner. - Highlights: • The Aβ peptide fibrilization process was followed by AFM and DP voltammetry. • The human Aβ{sub 1-40} and Aβ{sub 1

  20. Identification of Proteins and Peptide Biomarkers for Detecting Banned Processed Animal Proteins (PAPs) in Meat and Bone Meal by Mass Spectrometry.

    Science.gov (United States)

    Marbaix, Hélène; Budinger, Dimitri; Dieu, Marc; Fumière, Olivier; Gillard, Nathalie; Delahaut, Philippe; Mauro, Sergio; Raes, Martine

    2016-03-23

    The outbreak of bovine spongiform encephalopathy (BSE) in the United Kingdom in 1986, with processed animal proteins (PAPs) as the main vector of the disease, has led to their prohibition in feed. The progressive release of the feed ban required the development of new analytical methods to determine the exact origin of PAPs from meat and bone meal. We set up a promising MS-based method to determine the species and the source (legal or not) present in PAPs: a TCA-acetone protein extraction followed by a cleanup step, an in-solution tryptic digestion of 5 h (with a 1:20 protein/trypsin ratio), and mass spectrometry analyses, first without any a priori, with a Q-TOF, followed by a targeted triple-quadrupole analysis. Using this procedure, we were able to overcome some of the major limitations of the official methods to analyze PAPs, detecting and identifying prohibited animal products in feedstuffs by the monitoring of peptides specific for cows, pigs, and sheep in PAPs.