Albumin receptor effect may be due to a surface-induced conformational change in albumin

International Nuclear Information System (INIS)

Reed, R.G.; Burrington, C.M.

1989-01-01

To determine whether equilibrium binding between albumin and hepatocytes involves a cell surface receptor for albumin, we incubated freshly isolated rat hepatocytes with 125 I-albumin and determined the amount of albumin associated with the cells as a function of the total albumin concentration. The resulting two-phase binding curve showed the rat albumin-hepatocyte interaction to consist of a saturable binding interaction with a dissociation constant of 1.1 microM and 2 X 10(6) sites/cell in addition to a weak, nonsaturable binding interaction. However, the saturable binding of albumin to hepatocytes did not appear to result from the presence of an albumin receptor on the cell surface; the interaction was the same for different species of albumin, for chemically modified albumins, and for fragments of albumin representing mutually exclusive domains of the molecule. The saturable binding was, instead, found to involve a subpopulation of albumin with an enhanced affinity for the cell surface. We show that this subpopulation of albumin is generated upon contact with either solid surfaces or cell surfaces and can be transferred from one surface to another. We propose that the two-phase Scatchard binding curve and the ''albumin receptor effect'' reflect two populations of albumin that bind to the cell surface with different affinities rather than one population of albumin that binds to two classes of binding sites

Interaction of norfloxacin with bovine serum albumin studied by different spectrometric methods; displacement studies, molecular modeling and chemometrics approaches

Energy Technology Data Exchange (ETDEWEB)

Naseri, Abdolhossein, E-mail: a_naseri@tabrizu.ac.ir [Departments of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz 51666-16471 (Iran, Islamic Republic of); Hosseini, Soheila [Departments of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz 51666-16471 (Iran, Islamic Republic of); Rasoulzadeh, Farzaneh [Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz 51644-14766 (Iran, Islamic Republic of); Rashidi, Mohammad-Reza [Research Center for Pharmaceutical Nanotechnology, Tabriz University of Medical Sciences, Tabriz 51644-14766 (Iran, Islamic Republic of); Zakery, Maryam; Khayamian, Taghi [Department of Chemistry, College of Chemistry, Isfahan University of Technology, Isfahan 84154 (Iran, Islamic Republic of)

2015-01-15

Serum albumins as major target proteins can bind to other ligands leading to alteration of their pharmacological properties. The mechanism of interaction between norfloxacin (NFLX) with bovine serum albumin (BSA) was investigated. Fuorescence quenching of serum albumin by this drug was found to be a static quenching process. The binding sites number, n, apparent binding constant, K, and thermodynamic parameters were calculated at different temperatures. The distance, r, between donor, BSA, and acceptor, NFLX, was calculated according to the Forster theory of non-radiation energy transfer. Also binding characteristics of NFLX with BSA together with its displacement from its binding site by kanamycin and effect of common metal ions on binding constant were investigated by the spectroscopic methods. The conformational change in the secondary structure of BSA upon interaction with NFLX was investigated qualitatively from synchronous fluorescence spectra, Fourier Transform Infrared (FTIR) and circular dichroism (CD) spectrometric methods. Molecular docking studies were performed to obtain information on the possible residues involved in the interaction process and changes in accessible surface area of the interacting residues. The results showed that the conformation of BSA changed in the presence of NFLX. For the first time, displacement studies were used for this interaction; displacement studies showed that NFLX was displaced by phenylbutazon and ketoprofen but was not displaced by ibuprofen indicating that the binding site of NFLX on albumin was site I. In addition a powerful chemometrics method, multivariate curve resolution-alternating least square, was used for resolution of spectroscopic augmented data obtained in two different titration modes in order to extract spectral information regardless of spectral overlapping of components. - Highlights: • Interaction between norfloxacin and BSA is studied by spectral methods. • Chemometrics methods are used to

Fluorescent investigation of the interactions between N-(p-chlorophenyl)-N'-(1-naphthyl) thiourea and serum albumin: Synchronous fluorescence determination of serum albumin

International Nuclear Information System (INIS)

Cui Fengling; Wang Junli; Cui Yanrui; Li Jianping

2006-01-01

The interactions between N-(p-chlorophenyl)-N'-(1-naphthyl) thiourea and serum albumin were investigated by fluorescence spectroscopy and UV absorption spectrum under physiological conditions. The results of spectroscopic measurements suggested that N-(p-chlorophenyl)-N'-(1-naphthyl) thiourea should have a strong ability to quench the intrinsic fluorescence of both bovine serum albumin and human serum albumin through static quenching procedure, and the hydrophobic interaction was the predominant intermolecular force stabilizing the complex. Thermodynamic parameter enthalpy changes (ΔH) and entropy changes (ΔS) were calculated according to the Vant'Hoff equation. The binding distances between N-(p-chlorophenyl)-N'-(1-naphthyl) thiourea and the proteins were evaluated on the basis of the theory of Foester energy transfer. In addition, the effects of other ions on the binding constants of complexes were also discussed. Synchronous fluorescence technology was successfully applied to the determination of serum albumins added to the CPNT solution

Synthesis and characterisation of 8-hydroxyquinoline-bovine serum albumin conjugates as metal ion chelating proteins

International Nuclear Information System (INIS)

Giraudi, G.; Baggiani, C.; Giovannoli, C.; Marletto, C.; Vanni, A.

1999-01-01

A derivative of 8-hydroxyquinoline (8-quinolinol, oxine) with a linking bridge containing a carboxylic group was covalently coupled to bovine serum albumin by the N-hydroxysuccinimide method to obtain stable monomeric conjugates with oxine to protein mole ratios up to 37. These conjugates were characterised spectrophotometrically and their complexation properties were confirmed by spectral analysis with and without the addition of Al(III), Cd(II), Co(II), Cu(II), Hg(II), Mn(II), Ni(II), Pb(II), V(IV), U(VI) and Zn(II) ions added. The maximum number of ions bound by these chelating proteins was determined spectrophotometrically by titration with metal ions at pH 6.0. The conjugates with a substitution ratio (moles of 8-hydroxyquinoline bound/mole of albumin) less than about 8 showed 1:1 binding with metal ions, while conjugates with higher substitution ratios were able to complex with 2:1 ratio of 8-hydroxyquinoline to metal ion. Association and dissociation kinetics of complexation with copper(II) ions showed a complex mechanism. The spectral and binding properties of these metal ion-binding proteins confirm that the coupling of the 8-hydroxyquinoline derivative to bovine serum albumin gives stable, water soluble, macromolecular chelating agents that retain the complexing ability of the original ligand. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Interaction of glucocorticoids and progesterone derivatives with human serum albumin.

Science.gov (United States)

Abboud, Rola; Akil, Mohammad; Charcosset, Catherine; Greige-Gerges, Hélène

2017-10-01

Glucocorticoids (GCs) and progesterone derivatives (PGDs) are steroid hormones with well-known biological activities. Their interaction with human serum albumin (HSA) may control their distribution. Their binding to albumin is poorly studied in literature. This paper deals with the interaction of a series of GCs (cortisol, cortisone, prednisolone, prednisone, 6-methylprednisolone and 9-fluorocortisol acetate) and PGDs (progesterone, hydroxylated PGDs, methylated PGDs and dydrogesterone) with HSA solution (pH 7.4) at molar ratios steroid to HSA varying from 0 to 10. Similar titrations were conducted using Trp aqueous solution. Fluorescence titration method and Fourier transform infrared spectroscopy (FTIR) are used. PGDs (except dydrogesterone), cortisone and 9-fluorocortisol acetate affected weakly the fluorescence of Trp in buffer solution while they decreased in a dose-dependent manner that of HSA. Their binding constants to HSA were then calculated. Moreover, displacement experiment was performed using bilirubin as a site marker. The binding constant of bilirubin to albumin was determined in the absence and presence of a steroid at a molar ratio steroid to HSA of 1. The results indicate that the steroids bind to HSA at site I in a pocket different from that of bilirubin. Furthermore, the peak positions of amide I and amide II bands of HSA were shifted in the presence of progesterone, dydrogesterone and GCs. Also a variation was observed in amide I region indicating the formation of hydrogen bonding between albumin and steroids. Copyright © 2017 Elsevier B.V. All rights reserved.

Fluorescent investigation of the interactions between N-(p-chlorophenyl)-N'-(1-naphthyl) thiourea and serum albumin: Synchronous fluorescence determination of serum albumin

Energy Technology Data Exchange (ETDEWEB)

Cui Fengling [School of Chemistry and Environmental Science, Key Laboratory for Environmental Pollution Control Technology of Henan Province, Henan Normal University, Xinxiang, Hennan 453007 (China)]. E-mail: fenglingcui@hotmail.com; Wang Junli [School of Chemistry and Environmental Science, Key Laboratory for Environmental Pollution Control Technology of Henan Province, Henan Normal University, Xinxiang, Hennan 453007 (China); Cui Yanrui [School of Chemistry and Environmental Science, Key Laboratory for Environmental Pollution Control Technology of Henan Province, Henan Normal University, Xinxiang, Hennan 453007 (China); Li Jianping [School of Chemistry and Environmental Science, Key Laboratory for Environmental Pollution Control Technology of Henan Province, Henan Normal University, Xinxiang, Hennan 453007 (China)

2006-07-07

The interactions between N-(p-chlorophenyl)-N'-(1-naphthyl) thiourea and serum albumin were investigated by fluorescence spectroscopy and UV absorption spectrum under physiological conditions. The results of spectroscopic measurements suggested that N-(p-chlorophenyl)-N'-(1-naphthyl) thiourea should have a strong ability to quench the intrinsic fluorescence of both bovine serum albumin and human serum albumin through static quenching procedure, and the hydrophobic interaction was the predominant intermolecular force stabilizing the complex. Thermodynamic parameter enthalpy changes ({delta}H) and entropy changes ({delta}S) were calculated according to the Vant'Hoff equation. The binding distances between N-(p-chlorophenyl)-N'-(1-naphthyl) thiourea and the proteins were evaluated on the basis of the theory of Foester energy transfer. In addition, the effects of other ions on the binding constants of complexes were also discussed. Synchronous fluorescence technology was successfully applied to the determination of serum albumins added to the CPNT solution.

Characterizing the Interaction between tartrazine and two serum albumins by a hybrid spectroscopic approach.

Science.gov (United States)

Pan, Xingren; Qin, Pengfei; Liu, Rutao; Wang, Jing

2011-06-22

Tartrazine is an artificial azo dye commonly used in food products. The present study evaluated the interaction of tartrazine with two serum albumins (SAs), human serum albumin (HSA) and bovine serum albumin (BSA), under physiological conditions by means of fluorescence, three-dimensional fluorescence, UV-vis absorption, and circular dichroism (CD) techniques. The fluorescence data showed that tartrazine could bind to the two SAs to form a complex. The binding process was a spontaneous molecular interaction procedure, in which van der Waals and hydrogen bond interactions played a major role. Additionally, as shown by the UV-vis absorption, three-dimensional fluorescence, and CD results, tartrazine could lead to conformational and some microenvironmental changes of both SAs, which may affect the physiological functions of SAs. The work provides important insight into the mechanism of toxicity of tartrazine in vivo.

Interaction of carbon nanoparticles to serum albumin: elucidation of the extent of perturbation of serum albumin conformations and thermodynamical parameters

Energy Technology Data Exchange (ETDEWEB)

Mandal, Samir [Molecular and Human Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700032 (India); Hossain, Maidul [Biophysical Chemistry Laboratory, CSIR-Indian Institute of Chemical Biology, Kolkata 700032 (India); Devi, P. Sujatha [Nano-Structured Materials Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata 700032 (India); Kumar, Gopinatha Suresh [Biophysical Chemistry Laboratory, CSIR-Indian Institute of Chemical Biology, Kolkata 700032 (India); Chaudhuri, Keya, E-mail: keya.chaudhuri@gmail.com [Molecular and Human Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700032 (India)

2013-03-15

Highlights: ► Strong interaction of serum albumins to CNPs and potential toxicity. ► Partial unfolding and alteration of BSA and HSA secondary structure by CNP. ► Significant insight into design of nanoparticles in biomedical applications. -- Abstract: Carbon nanoparticles continuously generated from industries and vehicles due to incomplete combustion of fuels is one of the potent causes of air pollution. The exposure of this polluted air with carbon nanoparticles, introduced into the bloodstream of animals in the course of respiration, motivated us to study their interaction with plasma proteins, bovine serum albumin and human serum albumin. Carbon nanoparticles with very small size and high purity were synthesized by dehydration of D-glucose using concentrated sulphuric acid as dehydrating agent. These were characterized by transmission electron microscopy, atomic force microscopy, X-ray diffraction, Raman spectroscopy, FTIR spectroscopy and UV–visible spectroscopy. Carbon nanoparticles-protein interactions were studied by fluorescence spectroscopy, circular dichroism spectroscopy and isothermal titration calorimetry. The fluorescence quenching constants and thermodynamic parameters such as enthalpy change (ΔH°), entropy change (ΔS°) and free energy change (ΔG°) were calculated, which indicated a strong static quenching and primary electrostatic interaction between the carbon nanoparticles and blood proteins. Circular dichroism spectra provided the information about the secondary structure alteration of the proteins in presence of carbon nanoparticles. These findings have shed light towards an understanding of the interactions between carbon nanoparticles and serum proteins which may clarify the potential risks and undesirable health effects of carbon nanoparticles, as well as the related cellular trafficking and systemic translocation.

A multispectroscopic and molecular docking investigation of the binding interaction between serum albumins and acid orange dye

Science.gov (United States)

Naveenraj, Selvaraj; Solomon, Rajadurai Vijay; Mangalaraja, Ramalinga Viswanathan; Venuvanalingam, Ponnambalam; Asiri, Abdullah M.; Anandan, Sambandam

2018-03-01

The interaction of Acid Orange 10 (AO10) with bovine serum albumin (BSA) was investigated comparatively with that of human serum albumin (HSA) using multispectroscopic techniques for understanding their toxic mechanism. Further, density functional theory calculations and docking studies have been carried out to gain more insights into the nature of interactions existing between AO10 and serum albumins. The fluorescence results suggest that AO10 quenched the fluorescence of BSA through the combination of static and dynamic quenching mechanism. The same trend was followed in the interaction of AO10 with HSA. In addition to the type of quenching mechanism, the fluorescence spectroscopic results suggest that the binding occurs near the tryptophan moiety of serum albumins and the binding. AO10 has more binding affinity towards BSA than HSA. An AO10-Trp model has been created to explicitly understand the Csbnd Htbnd π interactions from Bader's quantum theory of atoms in molecules analysis which confirmed that AO10 bind more strongly with BSA than that of HSA due to the formation of three hydrogen bonds with BSA whereas it forms two hydrogen bonds in the case of HSA. These obtained results provide an in-depth understanding of the interaction of the acid azo dye AO10 with serum albumins. This interaction study provides insights into the underlying reasons for toxicity of AO10 relevant to understand its effect on bovids and humans during the blood transportation process.

The investigation of the interaction between edaravone and bovine serum albumin by spectroscopic approaches

International Nuclear Information System (INIS)

Yu Xianyong; Yang Ying; Liu Ronghua; Huang Haowen; Chen Jian; Ji Danhong; Li Xiaofang; Yang Fengxian; Yi Pinggui

2011-01-01

The fluorescence and ultraviolet spectroscopies were explored to study the interaction between edaravone (EDA) and bovine serum albumin (BSA) under imitated physiological condition. The experimental results show that the fluorescence quenching mechanism between EDA and BSA is a combined quenching (dynamic and static quenching). The binding constants, binding sites, and the corresponding thermodynamic parameters (ΔG, ΔH, and ΔS) of the interaction system were calculated at different temperatures. According to Foerster non-radiation energy transfer theory, the binding distance between EDA and BSA was calculated to be 3.10 nm. The effect of EDA on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy. In addition, the effects of some common metal ions Mg 2+ , Ca 2+ , Cu 2+ , and Ni 2+ on the binding constant between EDA and BSA were examined. - Highlights: → We explored the interaction of BSA and EDA using spectroscopic methods. → The fluorescence quenching mechanism is combined quenching. → Hydrophobic interaction force plays a major role in stabilizing the complex. → The binding constants, binding sites, and thermodynamic parameters were calculated. → EDA affects the conformation of tryptophan residue's microregion.

The investigation of the interaction between edaravone and bovine serum albumin by spectroscopic approaches

Energy Technology Data Exchange (ETDEWEB)

Xianyong, Yu; Ying, Yang; Ronghua, Liu; Haowen, Huang; Jian, Chen; Danhong, Ji [Key Laboratory of Theoretical Chemistry and Molecular Simulation of Ministry of Education, Hunan Province College Key Laboratory of QSAR/QSPR, School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201 (China); Li Xiaofang, E-mail: fine_chem@163.co [Key Laboratory of Theoretical Chemistry and Molecular Simulation of Ministry of Education, Hunan Province College Key Laboratory of QSAR/QSPR, School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201 (China); Fengxian, Yang [Key Laboratory of Theoretical Chemistry and Molecular Simulation of Ministry of Education, Hunan Province College Key Laboratory of QSAR/QSPR, School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201 (China); Yi Pinggui, E-mail: pgyi@hnust.c [Key Laboratory of Theoretical Chemistry and Molecular Simulation of Ministry of Education, Hunan Province College Key Laboratory of QSAR/QSPR, School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201 (China)

2011-07-15

The fluorescence and ultraviolet spectroscopies were explored to study the interaction between edaravone (EDA) and bovine serum albumin (BSA) under imitated physiological condition. The experimental results show that the fluorescence quenching mechanism between EDA and BSA is a combined quenching (dynamic and static quenching). The binding constants, binding sites, and the corresponding thermodynamic parameters ({Delta}G, {Delta}H, and {Delta}S) of the interaction system were calculated at different temperatures. According to Foerster non-radiation energy transfer theory, the binding distance between EDA and BSA was calculated to be 3.10 nm. The effect of EDA on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy. In addition, the effects of some common metal ions Mg{sup 2+}, Ca{sup 2+}, Cu{sup 2+}, and Ni{sup 2+} on the binding constant between EDA and BSA were examined. - Highlights: {yields} We explored the interaction of BSA and EDA using spectroscopic methods. {yields} The fluorescence quenching mechanism is combined quenching. {yields} Hydrophobic interaction force plays a major role in stabilizing the complex. {yields} The binding constants, binding sites, and thermodynamic parameters were calculated. {yields} EDA affects the conformation of tryptophan residue's microregion.

Circular dichroism study of the interaction between mutagens and bilirubin bound to different binding sites of serum albumins

Science.gov (United States)

Orlov, Sergey; Goncharova, Iryna; Urbanová, Marie

Although recent investigations have shown that bilirubin not only has a negative role in the organism but also exhibits significant antimutagenic properties, the mechanisms of interactions between bilirubin and mutagens are not clear. In this study, interaction between bilirubin bound to different binding sites of mammalian serum albumins with structural analogues of the mutagens 2-aminofluorene, 2,7-diaminofluorene and mutagen 2,4,7-trinitrofluorenone were investigated by circular dichroism and absorption spectroscopy. Homological human and bovine serum albumins were used as chiral matrices, which preferentially bind different conformers of bilirubin in the primary binding sites and make it observable by circular dichroism. These molecular systems approximated a real system for the study of mutagens in blood serum. Differences between the interaction of bilirubin bound to primary and to secondary binding sites of serum albumins with mutagens were shown. For bilirubin bound to secondary binding sites with low affinity, partial displacement and the formation of self-associates were observed in all studied mutagens. The associates of bilirubin bound to primary binding sites of serum albumins are formed with 2-aminofluorene and 2,4,7-trinitrofluorenone. It was proposed that 2,7-diaminofluorene does not interact with bilirubin bound to primary sites of human and bovine serum albumins due to the spatial hindrance of the albumins binding domains. The spatial arrangement of the bilirubin bound to serum albumin along with the studied mutagens was modelled using ligand docking, which revealed a possibility of an arrangement of the both bilirubin and 2-aminofluorene and 2,4,7-trinitrofluorenone in the primary binding site of human serum albumin.

Interaction of serum albumins with cyclodextrins: How safe is the use ...

Indian Academy of Sciences (India)

Interaction of cyclodextrins with human and bovine serum albumin: A combined spectroscopic and computational investigation. Saptarshi Ghosh, Bijan Kumar Paul, Nitin Chattopadhyay*. Department of Chemistry, Jadavpur University, Kolkata - 700 032, India. *Corresponding author: Fax: 91-33-2414 6584. E-mail: ...

An interaction of the functionalized closo-borates with albumins: The protein fluorescence quenching and calorimetry study

International Nuclear Information System (INIS)

Losytskyy, Mykhaylo Yu.; Kovalska, Vladyslava B.; Varzatskii, Oleg A.; Kuperman, Marina V.; Potocki, Slawomir; Gumienna-Kontecka, Elzbieta; Zhdanov, Andrey P.; Yarmoluk, Sergiy M.; Voloshin, Yan Z.; Zhizhin, Konstantin Yu.; Kuznetsov, Nikolai T.; Elskaya, Anna V.

2016-01-01

An interaction of the boron clusters closo-borates K 2 [B 10 H 10 ], K 2 [B 12 H 12 ] and their functionalized derivatives with serum proteins human (HSA) and bovine (BSA) albumins and immonoglobulin IgG as well as globular proteins β-lactoglobulin and lysozyme was characterized. The steady state and time resolved protein fluorescence quenching studies point on the binding of the closo-borate arylamine derivatives to serum albumins and discrimination of other proteins. The mechanism of the albumin fluorescence quenching by the closo-borate arylamine derivatives was proposed. The complex formation between albumin and the closo-borate molecules has been confirmed by isothermal titration calorimetry (ITC). The compound (K 2 [B 10 H 10 ]) and its arylamine derivative both interact with HSA, have close values of K a (1.4 and 1.2×10 3 M −1 respectively) and Gibbs energy (−17.9 and −17.5 kJ/mol respectively). However, the arylamine derivative forms complex with the higher guest/host binding ratio (4:1) comparing to the parent closo-borate (2:1). - Highlights: • Complex formation between boron clusters closo-borates and albumins was confirmed. • Functional substituent of closo-borate strongly affects its complex with albumins. • Binding of arylamine closo-borates essentially quench the albumin fluorescence. • Mechanism of tryptophan emission quenching by arylamine closo-borates was proposed.

Preparation of surface imprinted core-shell particles via a metal chelating strategy: specific recognition of porcine serum albumin

International Nuclear Information System (INIS)

Li, Qinran; Li, Senwu; Liu, Lukuan; Yang, Kaiguang; Zhang, Lihua; Liang, Zhen; Zhang, Yukui

2016-01-01

We describe the synthesis of molecularly imprinted core-shell microparticles via a metal chelating strategy that assists in the creation of selective recognition sites for albumin. Porcine serum albumin (PSA) was immobilized on silica beads via copper(II) chelation interaction. A solution containing 2-hydroxyethyl methacrylate and methacrylic acid as the monomers was mixed with the above particles, and free radical polymerization was performed at 25 °C. Copper ion and template were then removed to obtain PSA-imprinted core-shell particles (MIPs) with a typical diameter of 5 μm. The binding capacity of such MIP was 8.9 mg protein per gram of MIPs, and the adsorption equilibrium was established within <20 min. The imprinting factor for PSA reached 2.6 when the binding capacity was 7.7 mg protein per gram of MIPs. The use of such MIPs enabled PSA to be selectively recognized even in presence of the competitive proteins ribonuclease B, cytochrome c, and myoglobin. The results indicate that this imprinting strategy for protein may become a promising method to prepare MIPs for protein recognition. (author)

Interactions between 4-(2-dimethylaminoethyloxy)-N-octadecyl-1,8-naphthalimide and serum albumins: Investigation by spectroscopic approach

Energy Technology Data Exchange (ETDEWEB)

Sun Yang; Wei Song [School of Chemical Engineering, Northwest University, No. 229 Taibai North Road, Xi' an, Shaanxi 710069 (China); Zhao Yingyong [Biomedicine Key Laboratory of Shaanxi Province, Northwest University, No. 229 Taibai North Road, Xi' an, Shaanxi 710069 (China); Hu Xiaoyun, E-mail: hxy3275@nwu.edu.cn [Department of Physics, Northwest University, No. 229 Taibai North Road, Xi' an, Shaanxi 710069 (China); Fan Jun, E-mail: fanjun@nwu.edu.cn [School of Chemical Engineering, Northwest University, No. 229 Taibai North Road, Xi' an, Shaanxi 710069 (China)

2012-04-15

detection limit (3{sigma}) for HSA was 1.12 Multiplication-Sign 10{sup -10} M, for BSA it was 0.92 Multiplication-Sign 10{sup -10} M and for EA it was 4.33 Multiplication-Sign 10{sup -10} M. The effect of metal cations on the fluorescence spectra of DON in ethanol was also investigated. The method has been applied to detect the total proteins in human serum samples and the results were in good agreement with those reported by the hospital. - Highlights: Black-Right-Pointing-Pointer 4-(2-Dimethylaminoethyloxy)-N-octadecyl-1,8-naphthalimide (DON) was synthesized. Black-Right-Pointing-Pointer Effect of solvents on spectral characteristic of DON was investigated. Black-Right-Pointing-Pointer Interactions of DON with serum albumin were studied by spectral method. Black-Right-Pointing-Pointer A fluorometric method for determination of protein was developed.

Interactions between 4-(2-dimethylaminoethyloxy)-N-octadecyl-1,8-naphthalimide and serum albumins: Investigation by spectroscopic approach

International Nuclear Information System (INIS)

Sun Yang; Wei Song; Zhao Yingyong; Hu Xiaoyun; Fan Jun

2012-01-01

��10 M and for EA it was 4.33×10 −10 M. The effect of metal cations on the fluorescence spectra of DON in ethanol was also investigated. The method has been applied to detect the total proteins in human serum samples and the results were in good agreement with those reported by the hospital. - Highlights: ► 4-(2-Dimethylaminoethyloxy)-N-octadecyl-1,8-naphthalimide (DON) was synthesized. ► Effect of solvents on spectral characteristic of DON was investigated. ► Interactions of DON with serum albumin were studied by spectral method. ► A fluorometric method for determination of protein was developed.

Albumin and multiple sclerosis.

Science.gov (United States)

LeVine, Steven M

2016-04-12

Leakage of the blood-brain barrier (BBB) is a common pathological feature in multiple sclerosis (MS). Following a breach of the BBB, albumin, the most abundant protein in plasma, gains access to CNS tissue where it is exposed to an inflammatory milieu and tissue damage, e.g., demyelination. Once in the CNS, albumin can participate in protective mechanisms. For example, due to its high concentration and molecular properties, albumin becomes a target for oxidation and nitration reactions. Furthermore, albumin binds metals and heme thereby limiting their ability to produce reactive oxygen and reactive nitrogen species. Albumin also has the potential to worsen disease. Similar to pathogenic processes that occur during epilepsy, extravasated albumin could induce the expression of proinflammatory cytokines and affect the ability of astrocytes to maintain potassium homeostasis thereby possibly making neurons more vulnerable to glutamate exicitotoxicity, which is thought to be a pathogenic mechanism in MS. The albumin quotient, albumin in cerebrospinal fluid (CSF)/albumin in serum, is used as a measure of blood-CSF barrier dysfunction in MS, but it may be inaccurate since albumin levels in the CSF can be influenced by multiple factors including: 1) albumin becomes proteolytically cleaved during disease, 2) extravasated albumin is taken up by macrophages, microglia, and astrocytes, and 3) the location of BBB damage affects the entry of extravasated albumin into ventricular CSF. A discussion of the roles that albumin performs during MS is put forth.

An interaction of the functionalized closo-borates with albumins: The protein fluorescence quenching and calorimetry study

Energy Technology Data Exchange (ETDEWEB)

Losytskyy, Mykhaylo Yu., E-mail: mlosytskyy@gmail.com [Institute of Molecular Biology and Genetics, NASU, 150 Zabolotnogo Street, 03143 Kyiv (Ukraine); Kovalska, Vladyslava B. [Institute of Molecular Biology and Genetics, NASU, 150 Zabolotnogo Street, 03143 Kyiv (Ukraine); Varzatskii, Oleg A. [V. I. Vernadsky Institute of General and Inorganic Chemistry, 32/34 Palladin Avenue, 03080 Kyiv (Ukraine); Kuperman, Marina V. [Institute of Molecular Biology and Genetics, NASU, 150 Zabolotnogo Street, 03143 Kyiv (Ukraine); Potocki, Slawomir; Gumienna-Kontecka, Elzbieta [Faculty of Chemistry, Wroclaw University, 14F. Joliot-Curie Street, 50-383 Wroclaw (Poland); Zhdanov, Andrey P. [Kurnakov Institute of General and Inorganic Chemistry, 31 Leninskii Avenue, 119991 Moscow (Russian Federation); Yarmoluk, Sergiy M. [Institute of Molecular Biology and Genetics, NASU, 150 Zabolotnogo Street, 03143 Kyiv (Ukraine); Voloshin, Yan Z. [Nesmeyanov Institute of Organoelement Compounds, 28 Vavilova Street, 119991 Moscow (Russian Federation); Zhizhin, Konstantin Yu.; Kuznetsov, Nikolai T. [Kurnakov Institute of General and Inorganic Chemistry, 31 Leninskii Avenue, 119991 Moscow (Russian Federation); Elskaya, Anna V. [Institute of Molecular Biology and Genetics, NASU, 150 Zabolotnogo Street, 03143 Kyiv (Ukraine)

2016-01-15

An interaction of the boron clusters closo-borates K{sub 2}[B{sub 10}H{sub 10}], K{sub 2}[B{sub 12}H{sub 12}] and their functionalized derivatives with serum proteins human (HSA) and bovine (BSA) albumins and immonoglobulin IgG as well as globular proteins β-lactoglobulin and lysozyme was characterized. The steady state and time resolved protein fluorescence quenching studies point on the binding of the closo-borate arylamine derivatives to serum albumins and discrimination of other proteins. The mechanism of the albumin fluorescence quenching by the closo-borate arylamine derivatives was proposed. The complex formation between albumin and the closo-borate molecules has been confirmed by isothermal titration calorimetry (ITC). The compound (K{sub 2}[B{sub 10}H{sub 10}]) and its arylamine derivative both interact with HSA, have close values of K{sub a} (1.4 and 1.2×10{sup 3} M{sup −1} respectively) and Gibbs energy (−17.9 and −17.5 kJ/mol respectively). However, the arylamine derivative forms complex with the higher guest/host binding ratio (4:1) comparing to the parent closo-borate (2:1). - Highlights: • Complex formation between boron clusters closo-borates and albumins was confirmed. • Functional substituent of closo-borate strongly affects its complex with albumins. • Binding of arylamine closo-borates essentially quench the albumin fluorescence. • Mechanism of tryptophan emission quenching by arylamine closo-borates was proposed.

Interactions of hemin with bovine serum albumin and human hemoglobin: A fluorescence quenching study

Science.gov (United States)

Makarska-Bialokoz, Magdalena

2018-03-01

The binding interactions between hemin (Hmi) and bovine serum albumin (BSA) or human hemoglobin (HHb), respectively, have been examined in aqueous solution at pH = 7.4, applying UV-vis absorption, as well as steady-state, synchronous and three-dimensional fluorescence spectra techniques. Representative results received for both BSA and HHb intrinsic fluorescence proceeding from the interactions with hemin suggest the formation of stacking non-covalent and non-fluorescent complexes in both the Hmi-BSA and Hmi-HHb systems, with highly possible concurrent formation of a coordinate bond between a group on the protein surface and the metal in Hmi molecule. All the values of calculated parameters, the binding, fluorescence quenching and bimolecular quenching rate constants point to the involvement of static quenching in both the systems studied. The blue shift in the synchronous fluorescence spectra imply the participation of both tryptophan and tyrosine residues in quenching of BSA and HHb intrinsic fluorescence. Depicted outcomes suggest that hemin is supposedly able to influence the physiological functions of BSA and HHb, the most important blood proteins, particularly in case of its overuse.

Albumin and its application in drug delivery.

Science.gov (United States)

Sleep, Darrell

2015-05-01

Rapid clearance of drugs from the body results in short therapeutic half-life and is an integral property of many protein and peptide-based drugs. To maintain the desired therapeutic effect patients are required to administer higher doses more frequently, which is inconvenient and risks undesirable side effects. Drug delivery technologies aim to minimise the number of administrations and dose-related toxicity while maximising therapeutic efficacy. This review describes albumin's inherent biochemical and biophysical properties, which make it an attractive drug delivery platform and the developmental status of drugs that are associated, conjugated or genetically fused with albumin. Albumin interacts with a number of cell surface receptors including gp18, gp30, gp60, FcRn, cubilin and megalin. The importance of albumin's interaction with the FcRn receptor, the basis for albumin's long circulatory half-life, is described, as are engineered albumins with improved pharmacokinetics. Albumin naturally accumulates at tumours and sites of inflammation, a characteristic which can be augmented by the addition of targeting ligands. The development of albumin drug conjugates which reply upon this property is described. Albumin's inherent biochemical and biophysical properties make it an ideal drug delivery platform. Recent advances in our understanding of albumin physiology and the improvement in albumin-based therapies strongly suggest that albumin-based therapies have a significant advantage over alternative technologies in terms of half-life, stability, versatility, safety and ease of manufacture. Given the importance of the albumin:FcRn interaction, the interpretation of the pharmacokinetic and pharmacodynamic profiles of albumin-based therapeutics with disturbed albumin:FcRn interaction may have to be reassessed. The FcRn receptor has additional functionality, especially in relation to immunology, antigen presentation and delivery of proteins across mucosal membranes

The fluorescence spectroscopic studies on the interaction of novel aminophosphinic acids with bovine serum albumin

Energy Technology Data Exchange (ETDEWEB)

Kaboudin, B., E-mail: kaboudin@iasbs.ac.ir [Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Gava Zang, Zanjan 45137-66731 (Iran, Islamic Republic of); Moradi, K.; Faghihi, M.R.; Mohammadi, F. [Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Gava Zang, Zanjan 45137-66731 (Iran, Islamic Republic of)

2013-07-15

Six novel aminomethylphosphinic acids have been synthesized and characterized. The interaction between the aminophosphinic acids and bovine serum albumin (BSA) was investigated using fluorescence spectroscopy. The experimental results showed that the fluorescence quenching of BSA by aminophosphinic acids is a result of the formation of aminophosphinic acid–BSA complex; static quenching and non-radiative energy transferring were confirmed to result in the fluorescence quenching. The number of binding sites n, the apparent binding constant K{sub A} and the corresponding thermodynamic parameters were calculated at different temperatures. The process of binding of the aminophosphinic acid molecules to BSA was a spontaneous molecular interaction procedure in which entropy increased and Gibbs free energy decreased. Hydrophobic interaction force plays a major role in stabilizing the complex. The effect of aminophosphinic acids on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy. -- Graphical abstarct: The binding interactions of the water-soluble aminoalkylphosphinic acids APA 1–6 to bovine serum albumin (BSA) showed that the interaction process was spontaneous and the major interaction forces were found to be hydrophobic. Highlights: ► Binding of novel aminophosphinic acids with bovine serum albumin. ► Hydrophobic and hydrogen bonding attraction play major role in the binding process. ► Binding did not cause conformational changes in the protein. ► The quenching mechanism of fluorescence of BSA by aminophosphinic acids is a static quenching process.

The fluorescence spectroscopic studies on the interaction of novel aminophosphinic acids with bovine serum albumin

International Nuclear Information System (INIS)

Kaboudin, B.; Moradi, K.; Faghihi, M.R.; Mohammadi, F.

2013-01-01

Six novel aminomethylphosphinic acids have been synthesized and characterized. The interaction between the aminophosphinic acids and bovine serum albumin (BSA) was investigated using fluorescence spectroscopy. The experimental results showed that the fluorescence quenching of BSA by aminophosphinic acids is a result of the formation of aminophosphinic acid–BSA complex; static quenching and non-radiative energy transferring were confirmed to result in the fluorescence quenching. The number of binding sites n, the apparent binding constant K A and the corresponding thermodynamic parameters were calculated at different temperatures. The process of binding of the aminophosphinic acid molecules to BSA was a spontaneous molecular interaction procedure in which entropy increased and Gibbs free energy decreased. Hydrophobic interaction force plays a major role in stabilizing the complex. The effect of aminophosphinic acids on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy. -- Graphical abstarct: The binding interactions of the water-soluble aminoalkylphosphinic acids APA 1–6 to bovine serum albumin (BSA) showed that the interaction process was spontaneous and the major interaction forces were found to be hydrophobic. Highlights: ► Binding of novel aminophosphinic acids with bovine serum albumin. ► Hydrophobic and hydrogen bonding attraction play major role in the binding process. ► Binding did not cause conformational changes in the protein. ► The quenching mechanism of fluorescence of BSA by aminophosphinic acids is a static quenching process

β-Lactam antibiotics epitope mapping with STD NMR spectroscopy: a study of drug-human serum albumin interaction

International Nuclear Information System (INIS)

Milagre, Cintia D. F.; Cabeca, Luis F.; Almeida, Wanda P.; Marsaioli, Anita J.

2012-01-01

Molecular recognition events are key issues in many biological processes. STD NMR (saturation transfer difference nuclear magnetic resonance spectroscopy) is one of the techniques used to understand such biological interactions. Herein, we have investigated the interactions of four β-lactam antibiotics belonging to two classes (cephalosporins and penicillins) with human serum albumin (HSA) by 1 H STD NMR revealing that the interaction between the aromatic moiety and HSA is responsible for the binding efficiency. Thus, the structural differences from the five to six-membered thio ring in penicillins and cephalosporins do not seem to influence antibiotic albumin interactions. (author)

SERS spectroscopy of kaempferol and galangin under the interaction of human serum albumin with adsorbed silver nanoparticles

Science.gov (United States)

Zhang, Wei; Bai, Xueyuan; Wang, Yingping; Zhao, Bing; Zhao, Daqing; Zhao, Yu

Raman and surface-enhanced Raman scattering (SERS) spectroscopy were employed to probe the interaction of the flavonol drugs, kaempferol and galangin, with human serum albumin (HSA). SERS spectra of both flavonol derivatives were obtained from a colloidal silver surface in physiological condition, based on the high performance of the enhanced substrate, the most enhanced modes of kaempferol and galangin were those with certain motions perpendicular to the metal surface. The SERS spectra were allowed to predict similar orientation geometry for both of the drugs on the colloidal surface with minor difference. In addition, both flavonols-HSA complexes were prepared in different concentration ratios and the orientated differences between kaempferol and galangin were investigated by SERS.

[Changes in the secondary and tertiary structure of serum albumin in interactions with ligands of various structures].

Science.gov (United States)

Trinus, F P; Braver-Chernobul'skaia, B S; Luĭk, A I; Boldeskul, A E; Velichko, A N

1984-01-01

High affinity interactions between blood serum albumin and five substances of various chemical structure, exhibiting distinct physiological activity, were accompanied by alterations in the protein tertiary structure, while the albumin secondary structure was involved in conformational transformation after less effective affinity binding.

Interaction of silicon nanoparticles with the molecules of bovine serum albumin in aqueous solutions

International Nuclear Information System (INIS)

Anenkova, K A; Sergeeva, I A; Petrova, G P; Fedorova, K V; Osminkina, L A; Timoshenko, Viktor Yu

2011-01-01

Using the method of photon-correlation spectroscopy, the coefficient of translational diffusion D t and the hydrodynamic radius R of the particles in aqueous solutions of the bovine serum albumin, containing silicon nanoparticles, are determined. The character of the dependence of these parameters on the concentration of the protein indicates the absence of interaction between the studied particles in the chosen range of albumin concentrations 0.2 - 1.0 mg mL -1 . (optical technologies in biophysics and medicine)

Biological Interaction of Molybdenocene Dichloride with Bovine Serum Albumin Using Fluorescence Spectroscopy

Science.gov (United States)

Domínguez, Moralba; Cortes-Figueroa, Jose´ E.; Meléndez, Enrique

2018-01-01

Bioinorganic topics are ubiquitous in the inorganic chemistry curriculum; however, experiments to enhance understanding of related topics are scarce. In this proposed laboratory, upper undergraduate students assess the biological interaction of molybdenocene dichloride (Cp2MoCl2) with bovine serum albumin (BSA) by fluorescence spectroscopy.…

Biophysical studies of interaction between hydrolysable tannins isolated from Oenothera gigas and Geranium sanguineum with human serum albumin.

Science.gov (United States)

Sekowski, Szymon; Ionov, Maksim; Kaszuba, Mateusz; Mavlyanov, Saidmukhtar; Bryszewska, Maria; Zamaraeva, Maria

2014-11-01

Tannins, secondary plant metabolites, possess diverse biological activities and can interact with biopolymers such as lipids or proteins. Interactions between tannins and proteins depend on the structures of both and can result in changes in protein structure and activity. Because human serum albumin is the most abundant protein in plasma and responsible for interactions with important biological compounds (e.g. bilirubin) and proper blood pressure, therefore, it is very important to investigate reactions between HSA and tannins. This paper describes the interaction between human serum albumin (HSA) and two tannins: bihexahydroxydiphenoyl-trigalloylglucose (BDTG) and 1-O-galloyl-4,6-hexahydroxydiphenoyl-β-d-glucose (OGβDG), isolated from Geranium sanguineum and Oenothera gigas leafs, respectively. Optical (spectrofluorimetric) and chiral optical (circular dichroism) methods were used in this study. Fluorescence analysis demonstrated that OGβDG quenched HSA fluorescence more strongly than BDTG. Both OGβDG and BDTG formed complexes with albumin and caused a red shift of the fluorescence spectra but did not significantly change the protein secondary structure. Our studies clearly demonstrate that the tested tannins interact very strongly with human serum albumin (quenching constant K=88,277.26±407.04 M(-1) and K=55,552.67±583.07 M(-1) respectively for OGβDG and BDTG) in a manner depending on their chemical structure. Copyright © 2014 Elsevier B.V. All rights reserved.

Synergistic interaction between prolonged increased glycemic exposure and mildly increased urinary albumin excretion on diabetic retinopathy.

Science.gov (United States)

Moon, Shinje; Yoo, Hyung-Joon; Ahn, You-Hern; Kim, Gheun-Ho; Yu, Jae Myung; Park, Joon-Sung

2018-01-01

The association of mild increase in urinary albumin excretion with diabetic retinopathy (DR) in clinical studies is controversial. The aim of this study is to clarify the interaction between increased glycemic exposure and mild increase in urinary albumin excretion on risk of DR.Data were collected from the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2012. Overall, data from 953 participants without microalbuminuria (477 men and 476 women) were assessed. Logistic regression analysis was constructed to evaluate the association between DR and related clinical parameters, including urinary albumin-creatinine ratio (UACR, mg/g creatinine). The biological interaction of glycemic status and UACR on DR was evaluated by 3 indices: RERI, the relative excess risk due to the interaction; AP, the attributable proportion due to the interaction; and S, the additive interaction index of synergy.We found that UACR, glycated hemoglobin (HbA1c), and diabetic duration were deeply associated with increased risk of DR (UACR, odds ratio [OR] = 1.04, 95% confidence interval [CI] = 1.02-1.07; HbA1c, OR = 1.16, 95% CI = 1.04-1.30; diabetic duration, OR = 1.06, 95% CI = 1.04-1.07). Furthermore, our interaction analysis demonstrated that synergistic interaction between HbA1c and UACR on development of DR was prominent in participants with diabetic duration of ≥10 years (adjusted RERI = 0.92, 95% CI = 0.10-1.74; adjusted AP = 0.29, 95% CI = -0.82-1.41; adjusted S = 1.76, 95% CI = 1.27-2.25), but not subjects with shorter diabetic duration.These findings imply that there is the interaction between prolonged hyperglycemic exposure and increased urinary albumin excretion may exert additive synergistic effect on vascular endothelial dysfunction in the eye, even before the appearance of overt diabetic nephropathy. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

Fluorescent analysis of interaction of flavonols with hemoglobin and bovine serum albumin

Science.gov (United States)

Sentchouk, V. V.; Bondaryuk, E. V.

2007-09-01

We have studied the fluorescent properties of flavonols (quercetin, fisetin, morin, rutin) with the aim of studying possible interaction with hemoglobin and bovine serum albumin (BSA). We observed an increase in the intensity of intrinsic fluorescence for all the flavonols except rutin in the presence of BSA. From the changes in the fluorescence spectra, we concluded that tautomeric forms are formed on interaction with hemoglobin. We determined the interconnection between the structure of related flavonols and their fluorescent properties on interaction with proteins, and we determined the binding constants for binding with BSA and hemoglobin.

Spectroscopic analysis of the interaction between tetra-(p-sulfoazophenyl-4-aminosulfonyl-substituted aluminum (III phthalocyanines and serum albumins

Directory of Open Access Journals (Sweden)

Liqin Zheng

2017-03-01

Full Text Available The binding interaction between tetra-(p-sulfoazophenyl-4-aminosulfonyl-substituted aluminum (III phthalocyanine (AlPc, and two-serum albumins (bovine serum albumin (BSA and human serum albumin (HSA has been investigated. AlPc could quench the intrinsic fluorescence of BSA and HSA through a static quenching process. The primary and secondary binding sites of AlPc on BSA were domain I and III of BSA. The primary binding site of AlPc on HSA was domain I, and the secondary binding sites of AlPc on HSA were found at domains I and II. Our results suggest that AlPc readily interact with BSA and HSA implying that the amphiphilic substituents AlPc may contribute to their transportation in the blood.

Investigation into the interaction of methylparaben and erythromycin with human serum albumin using multispectroscopic methods.

Science.gov (United States)

Naik, Keerti M; Nandibewoor, Sharanappa T

2016-03-01

In this paper, the interaction of methylparaben and erythromycin with human serum albumin (HSA) was studied for the first time using spectroscopic methods including Fourier transform infrared (FTIR) spectroscopy and UV absorption spectroscopy in combination with fluorescence quenching under physiological conditions. The binding parameters were evaluated using a fluorescence quenching method. Based on Förster's theory of non-radiation energy transfer, the binding average distance, r between the donor (HSA) and the acceptor (methylparaben and erythromycin) was evaluated. UV/vis absorption, FTIR, synchronous and 3D spectral results showed that the conformation of HSA was changed in the presence of methylparaben and erythromycin. The thermodynamic parameters were calculated according to the van't Hoff equation and are discussed. The effect of some biological metal ions and site probes on the binding of methylparaben and erythromycin to HSA were further examined. Copyright © 2015 John Wiley & Sons, Ltd.

Characterization of the interaction between 3-Oxotabersonine and two serum albumins by using spectroscopic techniques

International Nuclear Information System (INIS)

Wang, Qing; Yan, Jin; He, Jiawei; Bai, Keke; Li, Hui

2013-01-01

3-Oxotabersonine (OTAB) is a component of Voacanga africana, which is a type of traditional drug in Africa widely used for treating diseases. This study examines the interaction of OTAB with bovine serum albumin (BSA) and human serum albumin (HSA) under physiological conditions. The interaction between OTAB and BSA/HSA was investigated using fluorescence spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, circular dichroism (CD) spectroscopy, and molecular modeling under simulated physiological conditions. The experimental results confirm that the quenching mechanism is a static quenching process. The binding site number (n) and the apparent binding constant (K) were measured at various temperatures. The thermodynamic parameters, namely, enthalpy change (ΔH) and entropy change (ΔS), were calculated. Furthermore, the structural changes in the serum albumin that affected the OTAB binding were determined using FT-IR. The binding site was assumed to be located in site I of the BSA/HSA (subdomain IIA). -- Highlights: ► Make use of the 3-Oxotabersonine firstly extracted from seeds of Voacanga africana Stapf to study the drug–protein system. ► Use two kinds of similar structure serum albumins to do a comparative study. ► FT-IR was used to study the conformational change of BSA and HSA. ► Use the BSA and HSA structure obtained from the Brookhaven Protein Data Bank for molecular docking

Characterization of the interaction between 3-Oxotabersonine and two serum albumins by using spectroscopic techniques

Energy Technology Data Exchange (ETDEWEB)

Wang, Qing; Yan, Jin; He, Jiawei; Bai, Keke [College of Chemical Engineering, Sichuan University, Chengdu 610065 (China); Li, Hui, E-mail: lihuilab@sina.com [College of Chemical Engineering, Sichuan University, Chengdu 610065 (China)

2013-06-15

3-Oxotabersonine (OTAB) is a component of Voacanga africana, which is a type of traditional drug in Africa widely used for treating diseases. This study examines the interaction of OTAB with bovine serum albumin (BSA) and human serum albumin (HSA) under physiological conditions. The interaction between OTAB and BSA/HSA was investigated using fluorescence spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, circular dichroism (CD) spectroscopy, and molecular modeling under simulated physiological conditions. The experimental results confirm that the quenching mechanism is a static quenching process. The binding site number (n) and the apparent binding constant (K) were measured at various temperatures. The thermodynamic parameters, namely, enthalpy change (ΔH) and entropy change (ΔS), were calculated. Furthermore, the structural changes in the serum albumin that affected the OTAB binding were determined using FT-IR. The binding site was assumed to be located in site I of the BSA/HSA (subdomain IIA). -- Highlights: ► Make use of the 3-Oxotabersonine firstly extracted from seeds of Voacanga africana Stapf to study the drug–protein system. ► Use two kinds of similar structure serum albumins to do a comparative study. ► FT-IR was used to study the conformational change of BSA and HSA. ► Use the BSA and HSA structure obtained from the Brookhaven Protein Data Bank for molecular docking.

Interaction of tea polyphenols with serum albumins: A fluorescence spectroscopic analysis

Energy Technology Data Exchange (ETDEWEB)

Bose, Adity, E-mail: adityc17j@gmail.com

2016-01-15

Interactions of some tea polyphenols, namely (−) Catechin (C), (−)-epicatechin (EC), (–) epicatechin-3-gallate (ECG), (−)-epigallocatechin (EGC) and (−)-epigallocatechin-3-gallate (EGCG) are outlined with the serum albumin proteins. These interactions had all resulted in binding with the proteins with a concomitant static quenching of the protein fluorescence. A fluorescence technique has been considered as the tool to comprehend the polyphenol–protein interactions mainly and simultaneously other spectroscopic techniques used to verify the results have been discussed. In this mini review the different types of equations usually employed to calculate the binding constant values have been outlined, namely, modified Stern Volmer plot, Scatchard plot and Lineweaver Burk equation, with their corresponding results. The n values (number of binding sites) had always been close to unity suggesting a 1:1 complexation with the polyphenols and the protein. A structural change in the polyphenols has been found to alter the binding constant value and the galloyl moiety attached to the C ring of the polyphenols have been found to play a crucial role in this regard. It has been found that an increase in galloyl moiety increases binding of the catechins with proteins. - Highlights: • Review on interactions of some tea polyphenols with the serum albumin proteins. • Tea polyphenols include Catechin, epigallocatechin-3-gallate, epigallocatechin, epicatechin-3-gallate and epicatechin. • Fluorescence spectroscopic technique is mainly outlined. • Binding constant studies have been given importance. • Galloyl moiety in the C ring is crucial in increasing binding constant.

[Binding interaction of harpagoside and bovine serum albumin: spectroscopic methodologies and molecular docking].

Science.gov (United States)

Cao, Tuan-Wu; Huang, Wen-Bing; Shi, Jian-Wei; He, Wei

2018-03-01

Scrophularia ningpoensis has exhibited a variety of biological activities and been used as a pharmaceutical product for the treatment of inflammatory ailment, rheumatoid arthritis, osteoarthritis and so on. Harpagoside (HAR) is considerer as a main bioactive compound in this plant. Serum albumin has important physiological roles in transportation, distribution and metabolism of many endogenous and exogenous substances in body. It is of great significance to study the interaction mechanism between HAR and bovine serum albumin (BSA). The mechanism of interaction between HAR and BSA was investigated using 2D and 3D fluorescence, synchronous florescence, ultraviolet spectroscopy and molecular docking. According to the analysis of fluorescence spectra, HAR could strongly quench the fluorescence of BSA, and the static quenching process indicated that the decrease in the quenching constant was observed with the increase in temperature. The magnitude of binding constants (KA) was more than 1×10⁵ L·mol⁻¹, and the number of binding sites(n) was approximate to 1. The thermodynamic parameters were calculated through analysis of fluorescence data with Stern-Volmer and Van't Hoff equation. The calculated enthalpy change (ΔH) and entropy change (ΔS) implied that the main interaction forces of HAR with BSA were the bonding interaction between van der Waals forces and hydrogen. The negative values of energy (ΔG) demonstrated that the binding of HAR with BSA was a spontaneous and exothermic process. The binding distance(r) between HAR and BSA was calculated to be about 2.80 nm based on the theory of Frster's non-radiation energy transfer, which indicated that energy is likely to be transfer from BSA to HAR. Both synchronous and 3D florescence spectroscopy clearly revealed that the microenvironment and conformation of BSA changed during the binding interaction between HAR and BSA. The molecular docking analysis revealed HAR is more inclined to BSA and human serum albumin

Study of the interaction between fluoxetine hydrochloride and bovine serum albumin in the imitated physiological conditions by multi-spectroscopic methods

International Nuclear Information System (INIS)

Katrahalli, Umesha; Jaldappagari, Seetharamappa; Kalanur, Shankara S.

2010-01-01

The mechanism of interaction of an antidepressant, fluoxetine hydrochloride (FLX) with bovine serum albumin (BSA) has been studied by different spectroscopic techniques under physiological conditions. FLX was found to quench the intrinsic fluorescence of protein by static quenching mechanism. The binding constant 'K' was found to be 7.06x10 3 M -1 at 296 K. The value of 'n' close to unity revealed that the BSA has a single class of binding site for FLX. Based on thermodynamic parameters, hydrogen bonding and van der Waals forces were proposed to operate between BSA and FLX. The change in conformation of protein was noticed upon its interaction with the drug. From displacement studies it was concluded that the FLX bound to protein at site I. The effects of various common metals ions on the binding were also investigated.

Study of Interactions of an Anticancer Drug Neratinib With Bovine Serum Albumin: Spectroscopic and Molecular Docking Approach

OpenAIRE

Tanveer A. Wani; Ahmed H. Bakheit; Ahmed H. Bakheit; M. A. Abounassif; Seema Zargar

2018-01-01

Binding of therapeutic agents to plasma proteins, particularly to serum albumin, provides valuable information in the drug development. This study was designed to evaluate the binding interaction of neratinib with bovine serum albumin (BSA). Neratinib blocks HER2 signaling and is effective in trastuzumab-resistant breast cancer treatment. Spectrofluorometric, UV spectrophotometric, and fourier transform infrared (FT-IR) and molecular docking experiments were performed to study this interactio...

[Study on the interaction of doxycycline with human serum albumin].

Science.gov (United States)

Hu, Tao-Ying; Chen, Lin; Liu, Ying

2014-05-01

The present study was designed to investigate the interaction of doxycycline (DC) with human serum albumin (HSA) by the inner filter effects, displacement experiments and molecular docking methods, based on classic multi-spectroscopy. With fluorescence quenching method at 298 and 310 K, the binding constants Ka, were determined to be 2. 73 X 10(5) and 0. 74X 10(5) L mol-1, respectively, and there was one binding site between DC and HSA, indicating that the binding of DC to HSA was strong, and the quenching mechanism was a static quenching. The thermodynamic parameters (enthalpy change, AH and enthropy change, delta S) were calculated to be -83. 55 kJ mol-1 and -176. 31 J mol-1 K-1 via the Vant' Hoff equation, which indicated that the interaction of DC with HSA was driven mainly by hydrogen bonding and van der Waals forces. Based on the Föster's theory of non-radiation energy transfer, the specific binding distance between Trp-214 (acceptor) and DC (donor) was 4. 98 nm, which was similar to the result confirmed by molecular docking. Through displacement experiments, sub-domain IIA of HSA was assigned to possess the high-affinity binding site of DC. Three-dimensional fluorescence spectra indicated that the binding of DC to HSA induced the conformation change of HSA and increased the disclosure of some part of hydrophobic regions that had been buried before. The results of FTIR spectroscopy showed that DC bound to HSA led to the slight unfolding of the polypeptide chain of HSA. Furthermore, the binding details between DC and HSA were further confirmed by molecular docking methods, which revealed that DC was bound at sub-domain IIA through multiple interactions, such as hydrophobic effect, polar forces and pi-pi interactions. The experimental results provide theoretical basis and reliable data for the study of the interaction between small drug molecule and human serum albumin

Thermodynamic studies on the interaction of folic acid with bovine serum albumin

International Nuclear Information System (INIS)

Jha, Niki S.; Kishore, Nand

2011-01-01

Research highlights: → Thermodynamics of binding of folic acid with bovine serum albumin studied. → Effect of co-solutes on binding permitted detailed analysis of interactions. → Electrostatic interactions dominate with contribution from hydrogen bonding. → No significant conformational change in protein observed upon drug binding. - Abstract: Binding of the vitamin folic acid with bovine serum albumin (BSA) has been studied using isothermal titration calorimetry (ITC) in combination with fluorescence and circular dichroism spectroscopies. The thermodynamic parameters of binding have been evaluated as a function of temperature, ionic strength, in the presence of nonionic surfactants triton X-100, tetrabutylammonium bromide, and sucrose. The values of the van't Hoff enthalpy calculated from the temperature dependence of the binding constant agree with the calorimetric enthalpies indicating that the binding of folic acid to the BSA is a two state process without involving intermediates. These observations are supported by the intrinsic fluorescence and circular dichroism spectroscopic measurements. With increase in the ionic strength, reduction in the binding affinity of folic acid to BSA is observed suggesting predominance of electrostatic interactions in the binding. The contribution of hydrophobic interactions in the binding is also demonstrated by decrease in the binding affinity in the presence of tetrabutylammonium bromide (TBAB). The value of binding affinity in the presence of sucrose indicates that hydrogen bonding also plays a significant contribution in the complexation process. The calorimetric and spectroscopic results provide quantitative information on the binding of folic acid to BSA and suggest that the binding is dominated by electrostatic interactions with contribution from hydrogen bonding.

Albumin-based drug delivery

DEFF Research Database (Denmark)

Larsen, Maja Thim; Kuhlmann, Matthias; Hvam, Michael Lykke

2016-01-01

The effectiveness of a drug is dependent on accumulation at the site of action at therapeutic levels, however, challenges such as rapid renal clearance, degradation or non-specific accumulation requires drug delivery enabling technologies. Albumin is a natural transport protein with multiple ligand...... binding sites, cellular receptor engagement, and a long circulatory half-life due to interaction with the recycling neonatal Fc receptor. Exploitation of these properties promotes albumin as an attractive candidate for half-life extension and targeted intracellular delivery of drugs attached by covalent...... conjugation, genetic fusions, association or ligand-mediated association. This review will give an overview of albumin-based products with focus on the natural biological properties and molecular interactions that can be harnessed for the design of a next-generation drug delivery platform....

Fatty Acid-Mediated Inhibition of Metal Binding to the Multi-Metal Site on Serum Albumin: Implications for Cardiovascular Disease.

Science.gov (United States)

Blindauer, Claudia A; Khazaipoul, Siavash; Yu, Ruitao; Stewart, Alan J

2016-01-01

Human serum albumin (HSA) is the major protein in blood plasma and is responsible for circulatory transport of a range of small molecules including fatty acids, metal ions and drugs. We previously identified the major plasma Zn2+ transport site on HSA and revealed that fatty-acid binding (at a distinct site called the FA2 site) and Zn2+ binding are interdependent via an allosteric mechanism. Since binding affinities of long-chain fatty acids exceed those of plasma Zn2+, this means that under certain circumstances the binding of fatty acid molecules to HSA is likely to diminish HSA Zn2+-binding, and hence affects the control of circulatory and cellular Zn2+ dynamics. This relationship between circulatory fatty acid and Zn2+ dynamics is likely to have important physiological and pathological implications, especially since it has been recognised that Zn2+ acts as a signalling agent in many cell types. Fatty acid levels in the blood are dynamic, but most importantly, chronic elevation of plasma fatty acid levels is associated with some metabolic disorders and disease states - including myocardial infarction and other cardiovascular diseases. In this article, we briefly review the metal-binding properties of albumin and highlight the importance of their interplay with fatty acid binding. We also consider the impact of this dynamic link upon levels and speciation of plasma Zn2+, its effect upon cellular Zn2+ homeostasis and its relevance to cardiovascular and circulatory processes in health and disease.

A model based on spectrofluorimetry to study the interaction between glyphosate and serum albumin of Salminus brasiliensis

Science.gov (United States)

Escobar, Marta Araujo Cyrino; Cortez, Celia Martins; Silva, Dilson; Neto, Jayme da Cunha Bastos

2017-11-01

The aim of this work is to initiate an investigation on the albumin of Salminus brasiliensis (gold fish) as a biomarker of environmental actions of glyphosate. We started using a mathematical-computational model based on spectrofluorimetric measurements to study the interaction of glyphosate with gold fish albumin and human serum albumin. Salminus brasiliensis is a migratory freshwater fish species found in southern and central-western Brazil, mainly in the Prata river basin, where most of soybean plantations are set. Glyphosate is a very used herbicide in this type of crop. Differently from the organophosphorate methyl parathion, glyphosate does not form complex with HSA, and the quenching constants estimated for its binding with gold fish albumin at 20 °C and 25 °C is 1.3(± 0.3) × 104 / M e 2.5 (± 0.3) × 104 / M, respectively.

Interaction of fibrinogen and albumin with titanium dioxide nanoparticles of different crystalline phases

International Nuclear Information System (INIS)

Marucco, Arianna; Fenoglio, Ivana; Turci, Francesco; Fubini, Bice

2013-01-01

TiO 2 nanoparticles (NPs) are contained in different kinds of industrial products including paints, self-cleaning glasses, sunscreens. TiO 2 is also employed in photocatalysis and it has been proposed for waste water treatment. Micrometric TiO 2 is generally considered a safe material, while there is concern on the possible health effects of nanometric titania. Due to their small size NPs may migrate within the human body possibly entering in the blood stream. Therefore studies on the interaction of NPs with plasma proteins are needed. In fact, the interaction with proteins is believed to ultimately influences the NPs biological fate. Fibrinogen and albumin are two of the most abundant plasma proteins. They are involved in several important physiological functions. Furthermore, fibrinogen is known to trigger platelet adhesion and inflammation. For these reasons the study of the interaction between these protein and nanoparticles is an important step toward the understanding of the behavior of NPs in the body. In this study we investigated the interaction of albumin and fibrinogen with TiO 2 nanoparticles of different crystal phases (rutile and anatase) using an integrated set of techniques. The amount of adsorbed fibrinogen and albumin for each TiO 2 surface was investigated by using the bicinchoninic acid assay (BCA). The variation of the surface charge of the NP-protein conjugates respect to the naked NPs was used to indirectly estimate both surface coverage and reversibility of the adsorption upon dilution. Surface charge was monitored by measuring the ζ potential with a conventional electrophoretic light scattering (ELS) system. The extent of protein deformation was evaluated by Raman Spectroscopy. We found that both proteins adsorb irreversibly against electrostatic repulsion, likely undergoing conformational changes or selective orientation upon adsorption. The size of primary particles and the particles aggregation rather than the crystal phase modulate the

Study of the interaction between fluoxetine hydrochloride and bovine serum albumin in the imitated physiological conditions by multi-spectroscopic methods

Energy Technology Data Exchange (ETDEWEB)

Katrahalli, Umesha [Department of Chemistry, Karnatak University, Dharwad 580 003 (India); Jaldappagari, Seetharamappa, E-mail: j_seetharam@rediffmail.co [Department of Chemistry, Karnatak University, Dharwad 580 003 (India); Kalanur, Shankara S. [Department of Chemistry, Karnatak University, Dharwad 580 003 (India)

2010-02-15

The mechanism of interaction of an antidepressant, fluoxetine hydrochloride (FLX) with bovine serum albumin (BSA) has been studied by different spectroscopic techniques under physiological conditions. FLX was found to quench the intrinsic fluorescence of protein by static quenching mechanism. The binding constant 'K' was found to be 7.06x10{sup 3} M{sup -1} at 296 K. The value of 'n' close to unity revealed that the BSA has a single class of binding site for FLX. Based on thermodynamic parameters, hydrogen bonding and van der Waals forces were proposed to operate between BSA and FLX. The change in conformation of protein was noticed upon its interaction with the drug. From displacement studies it was concluded that the FLX bound to protein at site I. The effects of various common metals ions on the binding were also investigated.

Bovine Serum Albumin Metal Complexes for Mimic of SOD

Indian Academy of Sciences (India)

Key Lab. Eco-Environment-Related Polymer Materials of Ministry of Education, Key Lab. ... scaffold and the metal complex functioned as the catalytic active center. ... small molecule.22 It is found that the antioxidative ... and absence, respectively, of the measured compound. ... monitor the interaction of metal ions with BSA.

Interaction between Saikosaponin D, Paeoniflorin, and Human Serum Albumin.

Science.gov (United States)

Liang, Guo-Wu; Chen, Yi-Cun; Wang, Yi; Wang, Hong-Mei; Pan, Xiang-Yu; Chen, Pei-Hong; Niu, Qing-Xia

2018-01-27

Saikosaponin D (SSD) and paeoniflorin (PF) are the major active constituents of Bupleuri Radix and Paeonia lactiflora Pall , respectively, and have been widely used in China to treat liver and other diseases for many centuries. We explored the binding of SSD/PF to human serum albumin (HSA) by using fluorospectrophotometry, circular dichroism (CD) and molecular docking. Both SSD and PF produced a conformational change in HSA. Fluorescence quenching was accompanied by a blue shift in the fluorescence spectra. Co-binding of PF and SSD also induced quenching and a conformational change in HSA. The Stern-Volmer equation showed that quenching was dominated by static quenching. The binding constant for ternary interaction was below that for binary interaction. Site-competitive experiments demonstrated that SSD/PF bound to site I (subdomain IIA) and site II (subdomain IIIA) in HSA. Analysis of thermodynamic parameters indicated that hydrogen bonding and van der Waals forces were mostly responsible for the binary association. Also, there was energy transfer upon binary interaction. Molecular docking supported the experimental findings in conformation, binding sites and binding forces.

Interaction of albumins and heparinoids investigated by affinity capillary electrophoresis and free flow electrophoresis.

Science.gov (United States)

Mozafari, Mona; El Deeb, Sami; Krull, Friederike; Wildgruber, Robert; Weber, Gerhard; Reiter, Christian G; Wätzig, Hermann

2018-02-01

A fast and precise affinity capillary electrophoresis (ACE) method has been applied to investigate the interactions between two serum albumins (HSA and BSA) and heparinoids. Furthermore, different free flow electrophoresis methods were developed to separate the species which appears owing to interaction of albumins with pentosan polysulfate sodium (PPS) under different experimental conditions. For ACE experiments, the normalized mobility ratios (∆R/R f ), which provided information about the binding strength and the overall charge of the protein-ligand complex, were used to evaluate the binding affinities. ACE experiments were performed at two different temperatures (23 and 37°C). Both BSA and HSA interact more strongly with PPS than with unfractionated and low molecular weight heparins. For PPS, the interactions can already be observed at low mg/L concentrations (3 mg/L), and saturation is already obtained at approximately 20 mg/L. Unfractionated heparin showed almost no interactions with BSA at 23°C, but weak interactions at 37°C at higher heparin concentrations. The additional signals also appeared at higher concentrations at 37°C. Nevertheless, in most cases the binding data were similar at both temperatures. Furthermore, HSA showed a characteristic splitting in two peaks especially after interacting with PPS, which is probably attributable to the formation of two species or conformational change of HSA after interacting with PPS. The free flow electrophoresis methods have confirmed and completed the ACE experiments. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterize the interaction between naringenin and bovine serum albumin using spectroscopic approach

International Nuclear Information System (INIS)

Hu Yanjun; Wang Yang; Ouyang Yu; Zhou Juan; Liu Yi

2010-01-01

Naringenin, a flavanone compound highly enriched in grapefruits, has been identified as a possible inhibitor of cell proliferation; and thus has the potential to act as an antitumorigenic agent. In this study, the binding of naringenin to bovine serum albumin (BSA) was studied at the physiological conditions (pH=7.40) by fluorescence and UV-vis spectroscopy. Naringenin strongly quenches the intrinsic fluorescence of BSA, and a decrease in the fluorescence quenching constant was observed together with an increase in temperature, which indicates that the fluorescence quenching of BSA by naringenin is a result of the formation of naringenin-BSA complex. Binding parameters calculating from Stern-Volmer method and Scatchard method showed that naringenin bind to BSA with the binding affinities of the order 10 4 L mol -1 . Thermodynamic parameters such as ΔG, ΔH and ΔS, were calculated at different temperatures, showing that electrostatic interactions were mostly responsible for the binding of naringenin to BSA. Site marker competitive displacement experiments demonstrating that naringenin bind with high affinity to site I (subdomain IIA) of BSA. Furthermore, the effect of metal ions to naringenin-BSA system was studied, and the specific binding distance r (3.30 nm) between donor (Trp-212) and acceptor (naringenin) was obtained according to fluorescence resonance energy transfer (FRET).

Quantitation of species differences in albumin–ligand interactions for bovine, human and rat serum albumins using fluorescence spectroscopy: A test case with some Sudlow's site I ligands

International Nuclear Information System (INIS)

Poór, Miklós; Li, Yin; Matisz, Gergely; Kiss, László; Kunsági-Máté, Sándor; Kőszegi, Tamás

2014-01-01

Albumin, the most abundant plasma protein is an approximately 67 kDa sized water-soluble macromolecule. Since several drugs and xenobiotics circulate in the blood at least partially in albumin-bound form, albumin plays a key role in the pharmacokinetics/toxicokinetics of these chemicals. Most of the drugs and xenobiotics are Sudlow's site I ligands. In numerous studies, bovine serum albumin (BSA) is used for modeling albumin–ligand interactions and the results are extrapolated to human serum albumin (HSA). Furthermore, only limited information is available related to albumin–ligand interactions of different albumin species. Therefore, in our study, we have focused on the quantification of differences between bovine, human and rat serum albumin (RSA) using four Sudlow's site I ligands (luteolin, ochratoxin A, phenylbutazone and warfarin). Interactions were analyzed by fluorescence spectroscopy. Stability constants as well as competing capacities of the ligands were determined, and thermodynamic study was also performed. Our results highlight that there could be major differences between BSA, HSA and RSA in their ligand binding properties. Based on our observations we emphasize that in molecular aspects BSA behaves considerably differently from HSA or from albumins of other species therefore, it is strongly recommended to apply at least some confirmatory measurements when data obtained from other species are attempted to be extrapolated to HSA. -- Highlights: • Albumin–ligand interactions of human, bovine and rat albumins were studied. • Four Sudlow's site I ligands were tested by fluorescence spectroscopy. • Substantial differences were found in stability constants among albumin complexes. • Competing capacity of ligands showed major differences in the studied species. • Data obtained for BSA cannot be directly extrapolated to human albumin

Studies on interaction between flavonoids and bovine serum albumin by spectral methods

International Nuclear Information System (INIS)

Shi Xiaolei; Li Xuwen; Gui Mingyu; Zhou Hongyu; Yang Ruijie; Zhang Hanqi; Jin Yongri

2010-01-01

The interaction between three kinds of flavonoids and bovine serum albumin (BSA) was investigated by fluorescence and UV-vis absorption spectrometry. The results indicated that flavonoids have strong ability to quench the intrinsic fluorescence of BSA by forming complexes. The binding constants, number of binding sites, thermodynamic parameters and energy transfer mechanisms were also investigated. Conformation change of BSA was observed from synchronous, three-dimensional fluorescence and circular dichroism spectrum.

Investigation of the interaction between isomeric derivatives and human serum albumin by fluorescence spectroscopy and molecular modeling

Energy Technology Data Exchange (ETDEWEB)

Wang, Ruiyong, E-mail: wangry@zzu.edu.cn; Dou, Huanjing; Yin, Yujing; Xie, Yuanzhe; Sun, Li; Liu, Chunmei; Dong, Jingjing; Huang, Gang; Zhu, Yanyan; Song, Chuanjun, E-mail: chjsong@zzu.edu.cn; Chang, Junbiao, E-mail: changjunbiao@zzu.edu.cn

2014-10-15

In this paper, we have synthesized 9H-pyrrolo[1,2-a]indol-9-ones and the isomeric indeno[2,1-b]pyrrol-8-ones. The interactions of human serum albumin with series of isomeric derivatives have been studied by spectrophotometric methods. Results show the intrinsic fluorescence is quenched by the derivatives with a static quenching procedure. The thermodynamics parameters indicate that van der Waals forces and hydrogen bonds play a major role in the interactions. The results of synchronous fluorescence spectra demonstrate that the microenvironments of Trp residue of human serum albumin are disturbed by most derivatives. Thermodynamic results showed that the 9H-pyrrolo[1,2-a]indol-9-ones are stronger quenchers and bind to human serum albumin with the higher affinity than isomeric indeno[2,1-b]pyrrol-8-ones. The influence of molecular structure on the binding aspects has been investigated. - Highlights: • The interactions between isomeric derivatives and HSA have been investigated. • Results reveal that 9H-pyrrolo[1,2-a]indol-9-ones are stronger quenchers for HSA. • Hydrogen bonds and van der Waals forces play major role in the binding process. • The influence of molecular structure on the binding aspects has been investigated. • The binding study was also modeled by molecular docking.

Investigation of the interaction between isomeric derivatives and human serum albumin by fluorescence spectroscopy and molecular modeling

International Nuclear Information System (INIS)

Wang, Ruiyong; Dou, Huanjing; Yin, Yujing; Xie, Yuanzhe; Sun, Li; Liu, Chunmei; Dong, Jingjing; Huang, Gang; Zhu, Yanyan; Song, Chuanjun; Chang, Junbiao

2014-01-01

In this paper, we have synthesized 9H-pyrrolo[1,2-a]indol-9-ones and the isomeric indeno[2,1-b]pyrrol-8-ones. The interactions of human serum albumin with series of isomeric derivatives have been studied by spectrophotometric methods. Results show the intrinsic fluorescence is quenched by the derivatives with a static quenching procedure. The thermodynamics parameters indicate that van der Waals forces and hydrogen bonds play a major role in the interactions. The results of synchronous fluorescence spectra demonstrate that the microenvironments of Trp residue of human serum albumin are disturbed by most derivatives. Thermodynamic results showed that the 9H-pyrrolo[1,2-a]indol-9-ones are stronger quenchers and bind to human serum albumin with the higher affinity than isomeric indeno[2,1-b]pyrrol-8-ones. The influence of molecular structure on the binding aspects has been investigated. - Highlights: • The interactions between isomeric derivatives and HSA have been investigated. • Results reveal that 9H-pyrrolo[1,2-a]indol-9-ones are stronger quenchers for HSA. • Hydrogen bonds and van der Waals forces play major role in the binding process. • The influence of molecular structure on the binding aspects has been investigated. • The binding study was also modeled by molecular docking

Investigation of Non-Covalent Interactions of Aflatoxins (B1, B2, G1, G2, and M1 with Serum Albumin

Directory of Open Access Journals (Sweden)

Miklós Poór

2017-10-01

Full Text Available Aflatoxins are widely spread mycotoxins produced mainly by Aspergillus species. Consumption of aflatoxin-contaminated foods and drinks causes serious health risks for people worldwide. It is well-known that the reactive epoxide metabolite of aflatoxin B1 (AFB1 forms covalent adducts with serum albumin. However, non-covalent interactions of aflatoxins with human serum albumin (HSA are poorly characterized. Thus, in this study the complex formation of aflatoxins was examined with HSA applying spectroscopic and molecular modelling studies. Our results demonstrate that aflatoxins form stable complexes with HSA as reflected by binding constants between 2.1 × 104 and 4.5 × 104 dm3/mol. A binding free energy value of −26.90 kJ mol−1 suggests a spontaneous binding process between AFB1 and HSA at room-temperature, while the positive entropy change of 55.1 JK−1 mol−1 indicates a partial decomposition of the solvation shells of the interacting molecules. Modeling studies and investigations with site markers suggest that Sudlow’s Site I of subdomain IIA is the high affinity binding site of aflatoxins on HSA. Interaction of AFB1 with bovine, porcine, and rat serum albumins was also investigated. Similar stabilities of the examined AFB1-albumin complexes were observed suggesting the low species differences of the albumin-binding of aflatoxins.

Thermodynamic Study of the Interaction of Bovine Serum Albumin and Amino Acids with Cellulose Nanocrystals

OpenAIRE

Lombardo, Salvatore; Eyley, Sam; Schütz, Christina; Van Gorp, Hans; Rosenfeldt, Sabine; Van den Mooter, Guy; Thielemans, Wim

2017-01-01

The interaction of bovine serum albumin (BSA) with sulfated, carboxylated, and pyridinium-grafted cellulose nanocrystals (CNCs) was studied as a function of the degree of substitution by determining the adsorption isotherm and by directly measuring the thermodynamics of interaction. The adsorption of BSA onto positively charged pyridinium-grafted cellulose nanocrystals followed Langmuirian adsorption with the maximum amount of adsorbed protein increasing linearly with increasing degree of sub...

Spectroscopic studies on the interaction between ZnSe nanoparticles with bovine serum albumin

International Nuclear Information System (INIS)

Chen, Zhi; Wu, Dudu

2012-01-01

The interaction between ZnSe nanoparticles (NPs) and bovine serum albumin (BSA) was studied by UV–vis, fluorescence spectroscopic techniques. The results showed that the fluorescence of BSA was strongly quenched by ZnSe NPs and the quenching mechanism was discussed to be a static quenching procedure, which was proved by quenching constant (K q ). The recorded UV–vis data and the fluorescence data quenching by the ZnSe NPs showed that the interaction between them leads to the formation of ZnSe–BSA complex. Based on the synchronous fluorescence spectra, it was established that the conformational change of BSA was induced by the interaction of ZnSe with the tyrosine micro-region of the BSA molecules. Furthermore, the temperature effects on the structural and spectroscopic properties of individual ZnSe NPs and protein and their bioconjugates (ZnSe–BSA) were also researched. It was found that, compared to the monotonic decrease of the individual ZnSe NPs fluorescence intensity, the temperature dependence of the ZnSe–BSA emission had a much more complex behavior, which was highly sensitive to the conformational changes of the protein. - Highlights: ►Interaction between bovine serum albumin (BSA) and ZnSe nanoparticles was studied. ► UV–vis data and fluorescence data demonstrated the formation of ZnSe–BSA complex. ► Temperature dependence of ZnSe–BSA emission was sensitive to the conformational changes of protein.

Interactions of cephalexin with bovine serum albumin: displacement reaction and molecular docking

Directory of Open Access Journals (Sweden)

Hamed Hamishehkar

2016-09-01

Conclusion: The outcomes of spectroscopic methods revealed that the conformation of BSA changed during drug-BSA interaction. The results of FRET propose that CPL quenches the fluorescence of BSA by static quenching and FRET. The displacement study showed that phenylbutazon and ketoprofen displaced CPL, indicating that its binding site on albumin is site I and Gentamicin cannot be displaced from the binding site of CPL. All results of molecular docking method agreed with the results of experimental data.

Fluorescence and Docking Studies of the Interaction between Human Serum Albumin and Pheophytin

Directory of Open Access Journals (Sweden)

Otávio Augusto Chaves

2015-10-01

Full Text Available In the North of Brazil (Pará and Amazonas states the leaves of the plant Talinum triangulare (popular: cariru replace spinach as food. From a phytochemical point of view, they are rich in compounds of the group of pheophytins. These substances, related to chlorophyll, have photophysical properties that give them potential application in photodynamic therapy. Human serum albumin (HSA is one of the main endogenous vehicles for biodistribution of molecules by blood plasma. Association constants and thermodynamic parameters for the interaction of HSA with pheophytin from Talinum triangulare were studied by UV-Vis absorption, fluorescence techniques, and molecular modeling (docking. Fluorescence quenching of the HSA’s internal fluorophore (tryptophan at temperatures 296 K, 303 K, and 310 K, resulted in values for the association constants of the order of 104 L∙mol−1, indicating a moderate interaction between the compound and the albumin. The negative values of ΔG° indicate a spontaneous process; ΔH° = 15.5 kJ∙mol−1 indicates an endothermic process of association and ΔS° = 0.145 kJ∙mol−1∙K−1 shows that the interaction between HSA and pheophytin occurs mainly by hydrophobic factors. The observed Trp fluorescence quenching is static: there is initial non-fluorescent association, in the ground state, HSA:Pheophytin. Possible solution obtained by a molecular docking study suggests that pheophytin is able to interact with HSA by means of hydrogen bonds with three lysine and one arginine residues, whereas the phytyl group is inserted in a hydrophobic pocket, close to Trp-214.

Bovine Serum Albumin binding to CoCrMo nanoparticles and the influence on dissolution

International Nuclear Information System (INIS)

Simoes, T A; Brown, A P; Milne, S J; Brydson, R M D

2015-01-01

CoCrMo alloys exhibit good mechanical properties, excellent biocompatibility and are widely utilised in orthopaedic joint replacements. Metal-on-metal hip implant degradation leads to the release of metal ions and nanoparticles, which persist through the implant's life and could be a possible cause of health complications. This study correlates preferential binding between proteins and metal alloy nanoparticles to the alloy's corrosion behaviour and the release of metal ions. TEM images show the formation of a protein corona in all particles immersed in albumin containing solutions. Only molybdenum release was significant in these tests, suggesting high dissolution of this element when CoCrMo alloy nanoparticles are produced as wear debris in the presence of serum albumin. The same trend was observed during extended exposure of molybdenum reference nanoparticles to albumin. (paper)

Fluorescence resonance energy transfer: A promising tool for investigation of the interaction between 1-anthracene sulphonate and serum albumins

International Nuclear Information System (INIS)

Banerjee, Paltu; Ghosh, Saptaparni; Sarkar, Arindam; Bhattacharya, Subhash Chandra

2011-01-01

This present investigation has revealed that steady state as well as time-resolved fluorescence techniques can serve as highly sensitive monitors for exploring the interaction of fluorescent probe 1-anthracene sulphonate (1-AS) with model transport proteins, bovine serum albumin (BSA) and human serum albumin (HSA).We have focused on fluorescence resonance energy transfer (FRET) between excited tryptophan in transport proteins to 1-AS, for the study of relaxation dynamics of biological molecules.

Quantitation of species differences in albumin–ligand interactions for bovine, human and rat serum albumins using fluorescence spectroscopy: A test case with some Sudlow's site I ligands

Energy Technology Data Exchange (ETDEWEB)

Poór, Miklós [Institute of Laboratory Medicine, University of Pécs, Ifjúság u. 13, Pécs H-7624 (Hungary); Li, Yin; Matisz, Gergely [Department of General and Physical Chemistry, University of Pécs, Pécs H-7624 (Hungary); János Szentágothai Research Center, Pécs H-7624 (Hungary); Kiss, László [Department of General and Physical Chemistry, University of Pécs, Pécs H-7624 (Hungary); Kunsági-Máté, Sándor [Department of General and Physical Chemistry, University of Pécs, Pécs H-7624 (Hungary); János Szentágothai Research Center, Pécs H-7624 (Hungary); Kőszegi, Tamás, E-mail: koszegit@freemail.hu [Institute of Laboratory Medicine, University of Pécs, Ifjúság u. 13, Pécs H-7624 (Hungary)

2014-01-15

Albumin, the most abundant plasma protein is an approximately 67 kDa sized water-soluble macromolecule. Since several drugs and xenobiotics circulate in the blood at least partially in albumin-bound form, albumin plays a key role in the pharmacokinetics/toxicokinetics of these chemicals. Most of the drugs and xenobiotics are Sudlow's site I ligands. In numerous studies, bovine serum albumin (BSA) is used for modeling albumin–ligand interactions and the results are extrapolated to human serum albumin (HSA). Furthermore, only limited information is available related to albumin–ligand interactions of different albumin species. Therefore, in our study, we have focused on the quantification of differences between bovine, human and rat serum albumin (RSA) using four Sudlow's site I ligands (luteolin, ochratoxin A, phenylbutazone and warfarin). Interactions were analyzed by fluorescence spectroscopy. Stability constants as well as competing capacities of the ligands were determined, and thermodynamic study was also performed. Our results highlight that there could be major differences between BSA, HSA and RSA in their ligand binding properties. Based on our observations we emphasize that in molecular aspects BSA behaves considerably differently from HSA or from albumins of other species therefore, it is strongly recommended to apply at least some confirmatory measurements when data obtained from other species are attempted to be extrapolated to HSA. -- Highlights: • Albumin–ligand interactions of human, bovine and rat albumins were studied. • Four Sudlow's site I ligands were tested by fluorescence spectroscopy. • Substantial differences were found in stability constants among albumin complexes. • Competing capacity of ligands showed major differences in the studied species. • Data obtained for BSA cannot be directly extrapolated to human albumin.

Interaction of indomethacin with adult human albumin and neonatal serum

DEFF Research Database (Denmark)

Honoré, B; Brodersen, R; Robertson, A

1983-01-01

The binding of indomethacin to albumin was investigated at 37 degrees C, pH 7.4. The first stoichiometric binding constant is 2.5 X 10(5) M-1. Indomethacin utilizes both the bilirubin and diazepam binding functions equally. The effect on bilirubin binding to albumin is negligible at therapeutic...

Effects of urea, metal ions and surfactants on the binding of baicalein with bovine serum albumin

Directory of Open Access Journals (Sweden)

Atanu Singha Roy

2016-08-01

Full Text Available The interaction of baicalein with bovine serum albumin (BSA was investigated with the help of spectroscopic and molecular docking studies. The binding affinity of baicalein towards BSA was estimated to be in order of 105 M−1 from fluorescence quenching studies. Negative ΔH° (−5.66±0.14 kJ/mol and positive (ΔS° (+79.96±0.65 J/mol K indicate the presence of electrostatic interactions along with the hydrophobic forces that result in a positive ΔS°. The hydrophobic association of baicalein with BSA diminishes in the presence of sodium dodecyl sulfate (SDS due to probable hydrophobic association of baicalein with SDS, resulting in a negative ΔS° (−40.65±0.87 J/mol K. Matrix-assisted laser desorption ionization/time of flight (MALDI--TOF experiments indicate a 1:1 complexation between baicalein and BSA. The unfolding and refolding phenomena of BSA were investigated in the absence and presence of baicalein using steady-state and fluorescence lifetime measurements. It was observed that the presence of urea ruptured the non-covalent interaction between baicalein and BSA. The presence of metal ions (Ag+, Mg2+, Ni2+, Mn2+, Co2+and Zn2+ increased the binding affinity of ligand towards BSA. The changes in conformational aspects of BSA after ligand binding were also investigated using circular dichroism (CD and Fourier transform infrared (FT-IR spectroscopic techniques. Site selectivity studies following molecular docking analyses indicated the binding of baicalein to site 1 (subdomain IIA of BSA.

The effect of paracetamol on 5 fluorouracil and bovine serum albumin interaction: A biophysical study

Science.gov (United States)

Dahiya, Vandana; Pal, Samanwita

2018-05-01

Serum Albumin is a major carrier protein and its binding with drugs is important to examine the change in pharmacokinetic properties due to interaction amongst drugs. In the present study we have attempted to understand the relevant drug-drug interaction (DDI) between two common drugs viz, paracetamol, an anti-inflammatory and fluorouracil, an anti-cancer drug. In-vitro spectroscopic methods viz., fluorescence quenching and UV-vis absorption have been employed for the drug-bovine serum albumin (BSA) complexes studies. The binding parameters and quenching constants have been determined for BSA-Paracetamol and BSA-5Fluorouracil complex according to literature models. It is also predicted from the quenching studies that BSA-5Fluorouracil is a stronger complex than BSA-Paracetamol. On the other hand paracetamol can alter binding affinity of 5Fluorouracil towards BSA. Hence it becomes clear that although the drugs could be administered simultaneously but they influence each other's binding with protein in a concentration dependent fashion. Further these results also indicate that availability of free 5Fluorouracil in blood may increase in presence of paracetamol.

Immunologic relationships of human serum albumin, macroaggregated albumin, and albumin microspheres

International Nuclear Information System (INIS)

Stang, P.C.; Roelands, J.F.; Cohen, P.

1975-01-01

Antigenic relationships of NSA (normal serum albumin), MAA (macroaggregated albumin), and HAM (human albumin microspheres) were determined in vivo in guinea pigs and in vitro in gel diffusion plates. Results showed that HAM could sensitize but seldom elicit anaphylaxis when used to challenge guinea pigs. In contrast, NSA and MAA were strong sensitizing antigens and inducers of anaphylaxis. The relative inability of HAM to induce anaphylaxis suggests that during production of the microspheres from soluble albumin, antigenic determinants of albumin may be altered or masked. Consequently, these determinants may be less available to react with antibody at the tissue sites

Study of interactions of an anticancer drug neratinib with bovine serum albumin: Spectroscopic and molecular docking approach

Science.gov (United States)

Wani, Tanveer A.; Bakheit, Ahmed H.; Abounassif, M. A.; Zargar, Seema

2018-03-01

Binding of therapeutic agents to plasma proteins, particularly to serum albumin, provides valuable information in the drug development. This study was designed to evaluate the binding interaction of neratinib with bovine serum albumin (BSA). Neratinib blocks HER2 signaling and is effective in trastuzumab-resistant breast cancer treatment. Spectrofluorometric, UV spectrophotometric, and fourier transform infrared (FT-IR) and molecular docking experiments were performed to study this interaction. The fluorescence of BSA is attributed to the presence of tryptophan (Trp) residues. The fluorescence of BSA in presence of neratinib was studied using the excitation wavelength of 280 nm and the emission was measured at 300-500 nm at three different temperatures. Neratinib quenched the BSA intrinsic fluorescence by static mechanism. A complex formation occurred due to the interaction leading to BSA absorption shift. The fluorescence, UV- absorption, three dimensional fluorescence and FT-IR data showed conformational changes occurred in BSA after interaction with neratinib. The binding constant values decreased as the temperature increased suggesting an instable complex formation at high temperature. Site I (sub-domain IIA) was observed as the principal binding site for neratinib. Hydrogen bonding and Van der Waals forces were suggested to be involved in the BSA-neratinib interaction due to the negative values of entropy and enthalpy changes.

Study of Interactions of an Anticancer Drug Neratinib With Bovine Serum Albumin: Spectroscopic and Molecular Docking Approach

Directory of Open Access Journals (Sweden)

Tanveer A. Wani

2018-03-01

Full Text Available Binding of therapeutic agents to plasma proteins, particularly to serum albumin, provides valuable information in the drug development. This study was designed to evaluate the binding interaction of neratinib with bovine serum albumin (BSA. Neratinib blocks HER2 signaling and is effective in trastuzumab-resistant breast cancer treatment. Spectrofluorometric, UV spectrophotometric, and fourier transform infrared (FT-IR and molecular docking experiments were performed to study this interaction. The fluorescence of BSA is attributed to the presence of tryptophan (Trp residues. The fluorescence of BSA in presence of neratinib was studied using the excitation wavelength of 280 nm and the emission was measured at 300-500 nm at three different temperatures. Neratinib quenched the BSA intrinsic fluorescence by static mechanism. A complex formation occurred due to the interaction leading to BSA absorption shift. The fluorescence, UV- absorption, three dimensional fluorescence and FT-IR data showed conformational changes occurred in BSA after interaction with neratinib. The binding constant values decreased as the temperature increased suggesting an instable complex formation at high temperature. Site I (sub-domain IIA was observed as the principal binding site for neratinib. Hydrogen bonding and Van der Waals forces were suggested to be involved in the BSA-neratinib interaction due to the negative values of entropy and enthalpy changes.

Recombinant albumin monolayers on latex particles.

Science.gov (United States)

Sofińska, Kamila; Adamczyk, Zbigniew; Kujda, Marta; Nattich-Rak, Małgorzata

2014-01-14

The adsorption of recombinant human serum albumin (rHSA) on negatively charged polystyrene latex micro-particles was studied at pH 3.5 and the NaCl concentration range of 10(-3) to 0.15 M. The electrophoretic mobility of latex monotonically increased with the albumin concentration in the suspension. The coverage of adsorbed albumin was quantitatively determined using the depletion method, where the residual protein concentration was determined by electrokinetic measurements and AFM imaging. It was shown that albumin adsorption was irreversible. Its maximum coverage on latex varied between 0.7 mg m(-2) for 10(-3) M NaCl to 1.3 mg m(-2) for 0.15 M NaCl. The latter value matches the maximum coverage previously determined for human serum albumin on mica using the streaming potential method. The increase in the maximum coverage was interpreted in terms of reduced electrostatic repulsion among adsorbed molecules. These facts confirm that albumin adsorption at pH 3.5 is governed by electrostatic interactions and proceeds analogously to colloid particle deposition. The stability of albumin monolayers was measured in additional experiments where changes in the latex electrophoretic mobility and the concentration of free albumin in solutions were monitored over prolonged time periods. Based on these experimental data, a robust procedure of preparing albumin monolayers on latex particles of well-controlled coverage and molecule distribution was proposed.

Raman studies of the interactions of fibrous carbon nanomaterials with albumin

Science.gov (United States)

Wesełucha-Birczyńska, Aleksandra; Morajka, Krzysztof; Stodolak-Zych, Ewa; Długoń, Elżbieta; Dużyja, Maria; Lis, Tomasz; Gubernat, Maciej; Ziąbka, Magdalena; Błażewicz, Marta

2018-05-01

Adsorption or immobilization of proteins on synthetic surfaces is a key issue in the context of the biocompatibility of implant materials, especially those intended for the needs of cardiac surgery but also for the construction of biosensors or nanomaterials used as drug carriers. The subject of research was the analysis of Raman spectra of two types of fibrous carbon nanomaterials, of great potential for biomedical applications, incubated with human serum albumin (HSA). The first nanomaterial has been created on the layer of MWCNTs deposited by electrophoretic method (EPD) and then covered by thin film of pyrolytic carbon introduced by chemical vapor deposition process (CVD). The second material was formed from carbonized nanofibers prepared via electrospinning (ESCNFs) of polyacrylonitrile (PAN) precursor and then covered with pyrolytic carbon (CVD). The G-band blue-shift towards the position of about 1600 cm-1, observed for both studied surfaces, clearly indicates the albumin (HSA) adhesion to the surface. The G and G' (2D) peak shift was employed to assess the stress build up on the carbon nanomaterials. The surface nano- and micro-topography as well as the method of ordering the carbon nanomaterial has a significant influence on the mode of surface-protein interaction.

3-hydroxyflavone-bovine serum albumin interaction in Dextran medium

Directory of Open Access Journals (Sweden)

Voicescu Mariana

2015-01-01

Full Text Available Spectroscopic analysis of a bioactive flavonol, 3-Hydroxyflavone (3-HF, in systems based on Dextran 70 (Dx70 (an important bio-relevant polysacharide and Bovine Serum Albumin (BSA (a carrier protein, have been studied by fluorescence and circular dichroism. Changes produced by different concentrations of Dx70 on the fluorescent characteristics of 3-HF, and on the excited - state intramolecular proton transfer (ESIPT process were studied. The influence of 3-HF binding and of Dx70 on the secondary structure of BSA were investigated by circular dichroism spectroscopy. The influence of temperature (30-80°C range on the intrinsic Tryptophan fluorescence in 3-HF/BSA/Dx70 systems, was investigated. The results are discussed with relevance to 3-HF as a sensitive fluorescence probe for exploring flavone-protein interaction in plasma expander media and also for its biological evaluation.

Interaction studies of resistomycin from Streptomyces aurantiacus AAA5 with calf thymus DNA and bovine serum albumin

Science.gov (United States)

Vijayabharathi, R.; Sathyadevi, P.; Krishnamoorthy, P.; Senthilraja, D.; Brunthadevi, P.; Sathyabama, S.; Priyadarisini, V. Brindha

2012-04-01

Resistomycin, a secondary metabolite produced by Streptomyces aurantiacus AAA5. The binding interaction of resistomycin with calf thymus DNA (CT DNA) and bovine serum albumin (BSA) was investigated by spectrophotometry, spectrofluorimetry, circular dichroism (CD) and synchronous fluorescence techniques under physiological conditions in vitro. Absorption spectral studies along with the fluorescence competition with ethidium bromide measurements and circular dichroism clearly suggest that the resistomycin bind with CT DNA relatively strong via groove binding. BSA interaction results revealed that the drug was found to quench the fluorescence intensity of the protein through a static quenching mechanism. The number of binding sites 'n' and apparent binding constant 'K' calculated according to the Scatchard equation exhibit a good binding property to bovine serum albumin protein. In addition, the results observed from synchronous fluorescence measurements clearly demonstrate the occurrence of conformational changes of BSA upon addition of the test compound.

Fluorescence study on the interaction of human serum albumin with Butein in liposomes

Science.gov (United States)

Toprak, Mahmut

2016-02-01

The interaction of Butein with human serum albumin in L-egg lecithin phosphatidycholine (PC) liposome has been investigated by fluorescence and absorption spectroscopy. The results of the fluorescence measurement indicated that Butein effectively quenched the intrinsic fluorescence of HSA via static quenching. The Stern-Volmer plots in all the liposome solutions showed a positive deviation from the linearity. According to the thermodynamic parameters, the hydrophobic interactions appeared be the major interaction forces between Butein and HSA. The effect of Butein on the conformation of HSA was also investigated by the synchronous fluorescence under the same experimental conditions. In addition, the partition coefficient of the Butein in the PC liposomes was also determined by using the fluorescence quenching process. The obtained results can be of biological significance in pharmacology and clinical medicine.

[Investigation on the interaction between pentadecafluorooctanoic acid and human serum albumin by capillary electrophoresis].

Science.gov (United States)

Gu, Yi; Guo, Ming; Lü, Da; Hou, Ping; Yin, Xinxin

2018-01-08

Capillary electrophoresis (CE) has been used to establish the analytical method of interaction between pentadecafluorooctanoic acid (PFOA) and human serum albumin (HSA). Under the physiological conditions, the interaction model of PFOA and HSA were constructed. Mobility method, plug-plug kinetic (PPK) method and simplified Hummel-Dreyer method were used to determine the interaction between derivatives and HSA. Non-linear regression, Scatchard equation and Klotz equation were adopted to obtain the interaction parameters. The results showed that all the three methods can be used to analyze the interaction of PFOA-HSA system. According to the interaction parameters, the most suitable CE method is simplified Hummel-Dreyer method while the most suitable theoretical equation is non-linear regression. The binding parameters indicated that the interaction of PFOA-HSA system has only one type of binding sites and the binding is stable. The research results have illustrated the interaction between HSA and PFOA, and provided a beneficial reference for in-depth research of the toxic mechanism of PFOA.

Fluorescence spectral studies on interaction of fluorescent probes with Bovine Serum Albumin (BSA)

Energy Technology Data Exchange (ETDEWEB)

Ghosh, Kaushik, E-mail: ghoshfcy@iitr.ac.in; Rathi, Sweety; Arora, Deepshikha

2016-07-15

Interaction of 2-(1-(naphthale-1-ylimino)ethyl)phenol (1), 2-methoxy-4-(((4-methoxyphenyl)imino)methyl)phenol (2) and 2-methoxy-4-((naphthalene-1-ylimino)methyl)phenol (3) with Bovine Serum Albumin (BSA) was examined. Fluorescence spectral data were obtained from the probes by varying the concentration of BSA as well as from BSA by varying the concentration of probes. Synchronous fluorescence measurements were performed and binding constants of the probes were calculated. To understand mode of quenching, Stern–Volmer plot, absorption spectral studies and life time measurements were performed. Förster resonance energy transfer (FRET) was also scrutinized. - Highlights: • Schiff bases with pendant phenolato function and interaction with BSA. • Synchronous fluorescence studies and a preferred interaction with tryptophan. • Probable interaction of probes with Trp-213 residue in the hydrophobic cavity. • 1:1 binding stoichiometry of probes and BSA in Benesi–Hildebrand graph.

Investigation on human serum albumin and Gum Tragacanth interactions using experimental and computational methods.

Science.gov (United States)

Moradi, Sajad; Taran, Mojtaba; Shahlaei, Mohsen

2018-02-01

The study on the interaction of human serum albumin and Gum Tragacanth, a biodegradable bio-polymer, has been undertaken. For this purpose, several experimental and computational methods were used. Investigation of thermodynamic parameters and mode of interactions were carried out using Fluorescence spectroscopy in 300 and 310K. Also, a Fourier transformed infrared spectra and synchronous fluorescence spectroscopy was performed. To give detailed insight of possible interactions, docking and molecular dynamic simulations were also applied. Results show that the interaction is based on hydrogen bonding and van der Waals forces. Structural analysis implies on no adverse change in protein conformation during binding of GT. Furthermore, computational methods confirm some evidence on secondary structure enhancement of protein as a presence of combining with Gum Tragacanth. Copyright © 2017 Elsevier B.V. All rights reserved.

Interactions of Poly(amidoamine) Dendrimers with Human Serum Albumin: Binding Constants and Mechanisms

OpenAIRE

Giri, Jyotsnendu; Diallo, Mamadou S.; Simpson, André J.; Liu, Yi; Goddard, William A., III; Kumar, Rajeev; Woods, Gwen C.

2011-01-01

The interactions of nanomaterials with plasma proteins have a significant impact on their in vivo transport and fate in biological fluids. This article discusses the binding of human serum albumin (HSA) to poly(amidoamine) [PAMAM] dendrimers. We use protein-coated silica particles to measure the HSA binding constants (K_b) of a homologous series of 19 PAMAM dendrimers in aqueous solutions at physiological pH (7.4) as a function of dendrimer generation, terminal group, and core chemistry. To g...

A facile route to glycated albumin detection.

Science.gov (United States)

Bohli, Nadra; Meilhac, Olivier; Rondeau, Philippe; Gueffrache, Syrine; Mora, Laurence; Abdelghani, Adnane

2018-07-01

In this paper we propose an easy way to detect the glycated form of human serum albumin which is biomarker for several diseases such as diabetes and Alzheimer. The detection platform is a label free impedimetric immunosensor, in which we used a monoclonal human serum albumin antibody as a bioreceptor and electrochemical impedance as a transducing method. The antibody was deposited onto a gold surface by simple physisorption technique. Bovine serum albumin was used as a blocking agent for non-specific binding interactions. Cyclic voltammetry and electrochemical impedance spectroscopy were used for the characterization of each layer. Human serum albumin was glycated at different levels with several concentrations of glucose ranging from 0 mM to 500 mM representing physiological, pathological (diabetic albumin) and suprapathological concentration of glucose. Through the calibration curves, we could clearly distinguish between two different areas related to physiological and pathological albumin glycation levels. The immunosensor displayed a linear range from 7.49% to 15.79% of glycated albumin to total albumin with a good sensitivity. Surface plasmon resonance imaging was also used to characterize the developed immunosensor. Copyright © 2018 Elsevier B.V. All rights reserved.

The attachment of metal-chelating groups to proteins: tagging of albumin by diazonium coupling and use of the products as radiopharmaceuticals

International Nuclear Information System (INIS)

Leung, C.S.H.; Meares, C.F.; Goodwin, D.A.

1978-01-01

The ability to attach firmly chelated metal ions or powerful chelating agents to sites on biological molecules can enhance the utility of a number of physical techniques now used in the study of biological systems. A 'bifunctional' chelating agent, containing both an EDTA group and a diazonium group, has been prepared and coupled to human serum albumin. The extent of labeling under various conditions and the amino-acid sidechains labeled have been investigated. The reaction of protein-bound chelating groups with added metal ions has been studied, with the finding that only about 40-50% of these groups are available to bind metal ions. Proteolysis of the products leads to recovery of full metal-binding capacity. Properties of the products in vivo are discussed. (author)

Spectroscopic studies of 7, 8-dihydroxy-4-methylcoumarin and its interaction with bovine serum albumin

Energy Technology Data Exchange (ETDEWEB)

Hussein, Belal H.M., E-mail: belalhussein102@yahoo.co [Chemistry Department, Faculty of Science, Suez Canal University, Ismailia 41522 (Egypt)

2011-05-15

The absorption and fluorescence spectra of 7, 8-dihydroxy-4-methylcoumarin (DHMC) in ethanol-water (1:9 v/v) solution at varying pH values were investigated . The interaction between DHMC and bovine serum albumin (BSA) was investigated by fluorescence, FT-IR, and circular dichroism (CD) spectroscopy. The Stern-Volmer quenching constant (K{sub SV}), the quenching rate constant of the bimolecular reaction (K{sub q}), the binding constant, and number of binding sites (n) of DHMC with BSA were evaluated. The results showed that DHMC quenches the fluorescence intensity of BSA through a static quenching process. Positive value of entropy change ({Delta}S) and negative value of enthalpy change ({Delta}H) of the BSA-DHMC interaction were obtained according to the van't Hoff equation. The interaction between DHMC and BSA was driven mainly by hydrophobic forces. The binding process was spontaneous and exothermic. The binding distance between the tryptophan residue in BSA and the DHMC was found to be about 2.6 nm based on the Foerster theory of non-radiation energy transfer. - Research highlights: {yields} 7,8-dihydroxy-4-methylcoumarin (DHMC) quenched the bovine serum albumin (BSA) fluorescence. {yields} The formation of the DHMC-BSA complex was spontaneous through a static quenching process. {yields} The polarity around the tryptophan residues decreased with the increase of DHMC concentration.

Calorimetric and spectroscopic studies of the interaction between zidovudine and human serum albumin

Science.gov (United States)

Pîrnău, Adrian; Mic, Mihaela; Neamţu, Silvia; Floare, Călin G.; Bogdan, Mircea

2018-02-01

A quantitative analysis of the interaction between zidovudine (AZT) and human serum albumin (HSA) was achieved using Isothermal titration calorimetry (ITC) in combination with fluorescence and 1H NMR spectroscopy. ITC directly measure the heat during a biomolecular binding event and gave us thermodynamic parameters and the characteristic association constant. By fluorescence quenching, the binding parameters of AZT-HSA interaction was determined and location to binding site I of HSA was confirmed. Via T1 NMR selective relaxation time measurements the drug-protein binding extent was evaluated as dissociation constants Kd and the involvement of azido moiety of zidovudine in molecular complex formation was put in evidence. All three methods indicated a very weak binding interaction. The association constant determined by ITC (3.58 × 102 M- 1) is supported by fluorescence quenching data (2.74 × 102 M- 1). The thermodynamic signature indicates that at least hydrophobic and electrostatic type interactions played a main role in the binding process.

Systematical investigation of in vitro interaction of InP/ZnS quantum dots with human serum albumin by multispectroscopic approach.

Science.gov (United States)

Huang, Shan; Qiu, Hangna; Liu, Yi; Huang, Chusheng; Sheng, Jiarong; Cui, Jianguo; Su, Wei; Xiao, Qi

2016-12-01

Cadmium-free quantum dots (QDs) have attracted great attention in biological and biomedical applications due to their less content of toxic metals, but their potential toxicity investigations on molecular biology level are rarely involved. Since few studies have addressed whether InP/ZnS QDs could bind and alter the structure and function of human serum albumin (HSA), in vitro interaction between InP/ZnS QDs and HSA was systematically characterized by multispectroscopic approaches. InP/ZnS QDs could quench the intrinsic fluorescence of HSA via static mode. The binding site of InP/ZnS QDs was mainly located at subdomain IIA of HSA. Some thermodynamic parameters suggested that InP/ZnS QDs interacted with HSA mainly through electrostatic interactions. As further revealed by three-dimensional spectrometry, FT-IR spectrometry and circular dichroism technique, InP/ZnS QDs caused more global and local conformational change of HSA than CdSe/ZnS QDs, which illustrated the stronger binding interaction and higher potential toxicity of InP/ZnS QDs on biological function of HSA. Our results offer insights into the in vitro binding mechanism of InP/ZnS QDs with HSA and provide important information for possible toxicity risk of these cadmium-free QDs to human health. Copyright © 2016 Elsevier B.V. All rights reserved.

Study on the interaction of the toxic food additive carmoisine with serum albumins: A microcalorimetric investigation

International Nuclear Information System (INIS)

Basu, Anirban; Kumar, Gopinatha Suresh

2014-01-01

Highlights: • Carmoisine binds to both the serum albumins with affinity of the order of 10 6 M −1 . • The binding was favored by negative enthalpy and positive entropy changes. • The binding was dominated by hydrophobic forces. • Carmoisine enhanced the thermal stability of both the proteins remarkably. - Abstract: The interaction of the synthetic azo dye and food colorant carmoisine with human and bovine serum albumins was studied by microcalorimetric techniques. A complete thermodynamic profile of the interaction was obtained from isothermal titration calorimetry studies. The equilibrium constant of the complexation process was of the order of 10 6 M −1 and the binding stoichiometry was found to be 1:1 with both the serum albumins. The binding was driven by negative standard molar enthalpy and positive standard molar entropy contributions. The binding affinity was lower at higher salt concentrations in both cases but the same was dominated by mostly non-electrostatic forces at all salt concentrations. The polyelectrolytic forces contributed only 5–8% of the total standard molar Gibbs energy change. The standard molar enthalpy change enhanced whereas the standard molar entropic contribution decreased with rise in temperature but they compensated each other to keep the standard molar Gibbs energy change almost invariant. The negative standard molar heat capacity values suggested the involvement of a significant hydrophobic contribution in the complexation process. Besides, enthalpy–entropy compensation phenomenon was also observed in both the systems. The thermal stability of the serum proteins was found to be remarkably enhanced on binding to carmoisine

Albumin has no role in the uptake of copper by human fibroblasts

International Nuclear Information System (INIS)

McArdle, H.J.; Guthrie, J.R.; Ackland, M.L.; Danks, D.M.

1987-01-01

The mechanism of copper uptake by cells has been the subject of controversy for some time. This paper examines the possibility of a role for albumin in the uptake of copper by fibroblasts. Although the cells could accumulate copper from a copper-albumin complex, there was no evidence for either copper-albumin or albumin receptors on the cell surface. The possibility of a surface exchange mechanism for copper was examined. While copper uptake showed saturation with increasing concentrations of labelled copper-albumin, adding unlabelled copper to the incubation medium did not inhibit uptake. Adding albumin or histidine to the copper-albumin complex resulted in an inhibition of copper uptake. The results can only be explained by the cell taking up free copper from the incubation medium, with the albumin then releasing its copper to maintain the equilibrium between free and bound metal. Since, in vivo there is essentially no free copper in serum, it is concluded that albumin is most unlikely to play a role in the uptake of copper by fibroblasts

Interaction of Palmitic Acid with Metoprolol Succinate at the Binding Sites of Bovine Serum Albumin

Directory of Open Access Journals (Sweden)

Mashiur Rahman

2014-12-01

Full Text Available Purpose: The aim of this study was to characterize the binding profile as well as to notify the interaction of palmitic acid with metoprolol succinate at its binding site on albumin. Methods: The binding of metoprolol succinate to bovine serum albumin (BSA was studied by equilibrium dialysis method (ED at 27°C and pH 7.4, in order to have an insight in the binding chemistry of the drug to BSA in presence and absence of palmitic acid. The study was carried out using ranitidine as site-1 and diazepam as site-2 specific probe. Results: Different analysis of binding of metoprolol succinate to bovine serum albumin suggested two sets of association constants: high affinity association constant (k1 = 11.0 x 105 M-1 with low capacity (n1 = 2 and low affinity association (k2 = 4.0×105 M-1 constant with high capacity (n2 = 8 at pH 7.4 and 27°C. During concurrent administration of palmitic acid and metoprolol succinate in presence or absence of ranitidine or diazepam, it was found that palmitic acid displaced metoprolol succinate from its binding site on BSA resulting reduced binding of metoprolol succinate to BSA. The increment in free fraction of metoprolol succinate was from 26.27% to 55.08% upon the addition of increased concentration of palmitic acid at a concentration of 0×10-5 M to 16×10-5 M. In presence of ranitidine and diazepam, palmitic acid further increases the free fraction of metoprolol succinate from 33.05% to 66.95% and 40.68% to 72.88%, respectively. Conclusion: This data provided the evidence of interaction at higher concentration of palmitic acid at the binding sites on BSA, which might change the pharmacokinetic properties of metoprolol succinate.

Metal interactions with boron clusters

International Nuclear Information System (INIS)

Grimes, R.N.

1982-01-01

This book presents information on the following topics: the structural and bonding features of metallaboranes and metallacarboranes; transition-metal derivatives of nido-boranes and some related species; interactions of metal groups with the octahydrotriborate (1-) anion, B 3 H 8 ; metallaboron cage compounds of the main group metals; closo-carborane-metal complexes containing metal-carbon and metal-boron omega-bonds; electrochemistry of metallaboron cage compounds; and boron clusters with transition metal-hydrogen bonds

Study of the interaction of kaempferol with bovine serum albumin

Science.gov (United States)

Tian, Jianniao; Liu, Jiaqin; Tian, Xuan; Hu, Zhide; Chen, Xingguo

2004-03-01

The binding of kaempferol with bovine serum albumin (BSA) was investigated at three temperatures, 296, 310 and 318 K, by the fluorescence, circular dichroism (CD) and Fourier transform infrared spectroscopy (FT-IR) at pH 7.40. The CD and FT-IR studies indicate that kaempferol binds strongly to BSA. The association constant K was determined by Stern-Volmer equation based on the quenching of the fluorescence BSA in the presence of kaempferol. The thermodynamic parameters were calculated according to the dependence of enthalpy change on the temperature as follows: Δ H0 and Δ S0 possess small negative (-1.694 kJ/mol) and positive values (88.814 J/mol K), respectively. According to the displacement experimental and the thermodynamic results, it is considered that kaempferol binding site II (subdomain III) mainly by hydrophobic interaction. The results studied by FT-IR and CD experiments indicate that the secondary structures of the protein have been changed by the interaction of kaempferol with BSA. The distance between the tryptophan residues in BSA and kaempferol bound to site II was estimated to be 2.78 nm using Foster's equation on the basis of fluorescence energy transfer.

Transendothelial albumin flux: evidence against active transport of albumin

International Nuclear Information System (INIS)

Siflinger-Birnboim, A.; Del Vecchio, P.J.; Cooper, J.A.; Malik, A.B.

1986-01-01

The authors studied whether albumin is actively transported across cultured pulmonary endothelium by comparing the transendothelial flux of 125 I-albumin from the luminal-to-abluminal side to the flux from the abluminal-to-luminal side. Bovine pulmonary artery endothelial cells were grown to confluence on gelatinized polycarbonated filters separating abluminal from luminal compartments. Each compartment had an albumin concentration of 1 g/100 ml to equalize oncotic pressure gradients. The effect of hydrostatic pressure was eliminated by maintaining an equal level of fluid in both compartments. The transendothelial flux of albumin across the monolayer was measured by placing 125 I-albumin tracer either on the luminal or the abluminal side. Equal fluxes of 125 I-albumin from luminal-to-abluminal side and from abluminal-to-luminal side were observed. The results indicate that the pulmonary endothelium behaves symmetrically for albumin, indicating the absence of active transport of albumin

Albumin's Influence on Carprofen Enantiomers-Hymecromone Interaction.

Science.gov (United States)

Tang, Mingjie; Guo, Yanjie; Gao, Youshui; Tang, Chao; Dang, Xiaoqian; Zhou, Zubin; Sun, Yuqiang; Wang, Kunzheng

2016-03-01

Hymecromone is an important coumarin drug, and carprofen is one of the most important nonsteroidal antiinflammatory drugs (NSAIDs). The present study aims to determine the influence of bovine serum albumin (BSA) on the carprofen-hymecromone interaction. The inhibition of carprofen enantiomers on the UDP-glucuronosyltransferase (UGT) 2B7-catalyzed glucuronidation of hymecromone was investigated in the UGTs incubation system with and without BSA. The inhibition capability of increased by 20% (P carprofen after the addition of 0.5% BSA in the incubation mixture. In contrast, no significant difference was observed for the inhibition of (S)-carprofen on UGT2B7 activity in the absence or presence of 0.5% BSA in the incubation system. The Lineweaver-Burk plot showed that the intersection point was located in the vertical axis, indicating the competitive inhibition of (R)-carprofen on UGT2B7 in the incubation system with BSA, which is consistent with the inhibition kinetic type of (R)-carprofen on UGT2B7 in the incubation system without BSA. Furthermore, the second plot using the slopes from the Lineweaver-Burk versus the concentrations of (R)-carprofen showed that the fitting equation was y=39.997x+50. Using this equation, the inhibition kinetic parameter was calculated to be 1.3 μM. For (S)-carprofen, the intersection point was located in the horizontal axis in the Lineweaver-Burk plot for the incubation system with BSA, indicating the noncompetitive inhibition of (S)-carprofen on the activity of UGT2B7. The fitting plot of the second plot was y=24.6x+180, and the inhibition kinetic parameter was 7.3 μM. In conclusion, the present study gives a short summary of BSA's influence on the carprofen enantiomers-hymecromone interaction, which will guide the clinical application of carprofen and hymecromone. © 2015 Wiley Periodicals, Inc.

Spectroscopic exploration of interaction between PEG-functionalized Ag2S nanoparticles with bovine serum albumin

Science.gov (United States)

Prasanth, S.; RitheshRaj, D.; Vineeshkumar, T. V.; Sudarsanakumar, C.

2018-05-01

The introduction of nanoparticles into biological fluids often leads to the formation of biocorona over the surface of nanoparticles. For the effective use of nanoparticles in biological applications it is very essential to understand their interactions with proteins. Herein, we investigated the interactions of Poly ethylene glycol capped Ag2S nanoparticles with Bovine Serum Albumin by spectroscopic techniques. By the addition of Ag2S nanoparticles, a ground state complex is formed. The CD spectroscopy reveals that the secondary structure of BSA is altered by complexation with PEG-Ag2S nanoparticles, while the overall tertiary structure remains closer to that of native BSA.

Comparative Interactions of Dihydroquinazolin Derivatives with Human Serum Albumin Observed via Multiple Spectroscopy

Directory of Open Access Journals (Sweden)

Yi Wang

2017-02-01

Full Text Available The interactions of dihydroquinazolines with human serum albumin (HSA were studied in pH 7.4 aqueous solution via fluorescence, circular dichroism (CD and Fourier transform infrared (FTIR spectroscopic techniques. In this work, 6-chloro-1-(3,3-dimethyl-butanoyl-2(unsubstitutedphenyl-2,3-dihydroquinazolin-4(1H-one (PDQL derivatives were designed and synthesized to study the impact of five similar substituents (methyl, methoxy, cyano, trifluoromethyl and isopropyl on the interactions between PDQL and HSA using a comparative methodology. The results revealed that PDQL quenched the intrinsic fluorescence of HSA through a static quenching process. Displacement experiments with site-specific markers revealed that PDQL binds to HSA at site II (subdomain IIIA and that there may be only one binding site for PDQL on HSA. The thermodynamic parameters indicated that hydrophobic interactions mainly drove the interactions between PDQL and HSA. The substitution using five similar groups in the benzene ring could increase the interactions between PDQL and HSA to some extent through the van der Waals force or hydrogen bond effects in the proper temperature range. Isopropyl substitution could particularly enhance the binding affinity, as observed via comparative studies

Characterization of the Interaction between Eupatorin and Bovine Serum Albumin by Spectroscopic and Molecular Modeling Methods

Science.gov (United States)

Xu, Hongliang; Yao, Nannan; Xu, Haoran; Wang, Tianshi; Li, Guiying; Li, Zhengqiang

2013-01-01

This study investigated the interaction between eupatorin and bovine serum albumin (BSA) using ultraviolet-visible (UV-vis) absorption, fluorescence, synchronous fluorescence, circular dichroism (CD) spectroscopies, and molecular modeling at pH 7.4. Results of UV-vis and fluorescence spectroscopies illustrated that BSA fluorescence was quenched by eupatorin via a static quenching mechanism. Thermodynamic parameters revealed that hydrophobic and electrostatic interactions played major roles in the interaction. Moreover, the efficiency of energy transfer, and the distance between BSA and acceptor eupatorin, were calculated. The effects of eupatorin on the BSA conformation were analyzed using UV-vis, CD, and synchronous fluorescence. Finally, the binding of eupatorin to BSA was modeled using the molecular docking method. PMID:23839090

Urine Albumin and Albumin/ Creatinine Ratio

Science.gov (United States)

... it used? The urine albumin test or albumin/creatinine ratio (ACR) is used to screen people with chronic conditions, such as diabetes and high blood pressure ( hypertension ) that put them at an ...

Interaction of 1-pyrene sulfonic acid sodium salt with human serum albumin

Energy Technology Data Exchange (ETDEWEB)

Steblecka, Malgorzata, E-mail: gosia@mitr.p.lodz.pl; Wolszczak, Marian, E-mail: marianwo@mitr.p.lodz.pl; Szajdzinska-Pietek, Ewa, E-mail: espietek@mitr.p.lodz.pl

2016-04-15

Steady state and time-resolved techniques of optical spectroscopy were applied to examine the interaction between 1-pyrene sulfonic acid (PSA) sodium salt and human serum albumin (HSA). This work is directed towards finding a convenient fluorescent marker (or blocker) of hydrophobic binding sites within the protein, to be used in the in vitro studies of HSA−drug systems. The observed variation of PSA absorbance with HSA concentration was interpreted in terms of two possible probe/protein binding modes with the binding constants K{sub b,1}=(6.5±0.6)∙10{sup 6} M{sup −1} (a specific receptor site), and K{sub b,2}=(3.8±0.8)∙10{sup 5} M{sup −1} (non-specific binding of up to three probe molecules). The PSA fluorescence is quenched by the albumin (via both static and dynamic mechanisms), and also the HSA–Trp214 fluorescence is quenched by PSA (via resonance energy transfer). These results indicate that the probe is bound in the domain IIA of the secondary HSA structure. At lower [PSA]/[HSA] ratios the PSA fluorescence lifetime is longer than that in homogeneous buffer solutions (not containing HSA). Therefore, we conclude that lower affinity binding sites are distant from the tryptophan residue. This is confirmed by complementary studies on the transient T–T absorbance and on luminescence of the photosensitized singlet oxygen.

Molecular basis of indomethacin-human serum albumin interaction

DEFF Research Database (Denmark)

Trivedi, V D; Vorum, H; Honoré, B

1999-01-01

Studies on the strength and extent of binding of the non-steroidal anti-inflammatory drug indomethacin to human serum albumin (HSA) have provided conflicting results. In the present work, the serum-binding of indomethacin was studied in 55 mM sodium phosphate buffer (pH 7.0) at 28 degrees C, by u...

Micropinocytic ingestion of glycosylated albumin by isolated microvessels: possible role in pathogenesis of diabetic microangiopathy.

OpenAIRE

Williams, S K; Devenny, J J; Bitensky, M W

1981-01-01

Microvessels isolated from rat epididymal fat exhibit differential vesicular ingestion rates for unmodified and non-enzymatically glycosylated rat albumin. While unmodified rat albumin is excluded from ingestion by endothelial micropinocytic vesicles, glycosylated albumin is avidly taken up by endocytosis. Interaction of albumin and glycosylated albumin with endothelium was studied with a double-label fluorescence assay of micropinocytosis. When glycosylated albumin was present at a concentra...

Spectroscopic investigation on the interaction of titanate nanotubes with bovine serum albumin

International Nuclear Information System (INIS)

Zhao, L.Z.; Zhao, Y.S.; Teng, H.H.; Shi, S.Y.; Ren, B.X.

2014-01-01

In order to understand the transport mechanism and evaluate the biological safety of titanate nanotubes, the interactions of titanate nanotubes (TNTs) with bovine serum albumin (BSA) were investigated by applying spectroscopic methods under simulated physiological conditions. After taking into account the inner filter effect, the fluorescence intensity of BSA was found to be significantly enhanced by the presence of TNTs, indicating that the microenvironment of tryptophan and tyrosine residues in BSA became more hydrophobic. In addition, the absorption spectra of BSA showed a hyperchromic effect around 280 nm as the concentration of TNTs increased, suggesting that TNTs changed the microenvironment of the tryptophan and tyrosine residues. This is consistent with the results from fluorescence spectroscopy studies. However, circular dichroism spectroscopy revealed that no significant conformational change in BSA occurred during the interaction. We believe that Trp-213 was buried more compactly in the internal hydrophobic region, and hydrophobicity increased around Trp-134 with increasing TNTs concentration. From a spectroscopic point of view, this work elucidates the interaction mechanism of titanate nanotubes with BSA, and the methods used in this paper can also be applied to explore the molecular mechanism underlying toxicity of other nanomaterials. (authors)

Molecular Structure-Affinity Relationship of Flavonoids in Lotus Leaf (Nelumbo nucifera Gaertn.) on Binding to Human Serum Albumin and Bovine Serum Albumin by Spectroscopic Method.

Science.gov (United States)

Tang, Xiaosheng; Tang, Ping; Liu, Liangliang

2017-06-23

Lotus leaf has gained growing popularity as an ingredient in herbal formulations due to its various activities. As main functional components of lotus leaf, the difference in structure of flavonoids affected their binding properties and activities. In this paper, the existence of 11 flavonoids in lotus leaf extract was confirmed by High Performance Liquid Chromatography (HPLC) analysis and 11 flavonoids showed various contents in lotus leaf. The interactions between lotus leaf extract and two kinds of serum albumins (human serum albumin (HSA) and bovine serum albumin (BSA)) were investigated by spectroscopic methods. Based on the fluorescence quenching, the interactions between these flavonoids and serum albumins were further checked in detail. The relationship between the molecular properties of flavonoids and their affinities for serum albumins were analyzed and compared. The hydroxylation on 3 and 3' position increased the affinities for serum albumins. Moreover, both of the methylation on 3' position of quercetin and the C₂=C₃ double bond of apigenin and quercetin decreased the affinities for HSA and BSA. The glycosylation lowered the affinities for HSA and BSA depending on the type of sugar moiety. It revealed that the hydrogen bond force played an important role in binding flavonoids to HSA and BSA.

Albumin-based drug delivery: harnessing nature to cure disease.

Science.gov (United States)

Larsen, Maja Thim; Kuhlmann, Matthias; Hvam, Michael Lykke; Howard, Kenneth A

2016-01-01

The effectiveness of a drug is dependent on accumulation at the site of action at therapeutic levels, however, challenges such as rapid renal clearance, degradation or non-specific accumulation requires drug delivery enabling technologies. Albumin is a natural transport protein with multiple ligand binding sites, cellular receptor engagement, and a long circulatory half-life due to interaction with the recycling neonatal Fc receptor. Exploitation of these properties promotes albumin as an attractive candidate for half-life extension and targeted intracellular delivery of drugs attached by covalent conjugation, genetic fusions, association or ligand-mediated association. This review will give an overview of albumin-based products with focus on the natural biological properties and molecular interactions that can be harnessed for the design of a next-generation drug delivery platform.

Molecular modeling and multispectroscopic studies of the interaction of hepatitis B drug, adefovir dipivoxil with human serum albumin

International Nuclear Information System (INIS)

Shahabadi, Nahid; Falsafi, Monireh; Hadidi, Saba

2015-01-01

The interaction of hepatitis B drug, adefovir dipivoxil with human serum albumin (HSA) was studied by using UV–vis, fluorometric, circular dichroism (CD) and molecular docking techniques. The results indicated that the binding of the drug to HSA caused fluorescence quenching through static quenching mechanism with binding constant of 1.3×103 M −1 . The thermodynamic parameters indicated that the hydrophobic force contacts are the major forces in the stability of protein-drug complex (ΔH>0 and ΔS>0). The displacement experiments using the site probes viz., warfarin and ibuprofen showed that adefovir dipivoxil could bind to the site III of HSA. The results of CD and UV–vis spectroscopy indicated that the binding of the drug induced some conformational changes in HSA. Furthermore, the study of molecular docking also confirmed binding of adefovir dipivoxil to the site III of HSA by hydrophobic interaction. - Highlights: • The interaction of adefovir dipivoxil, drug for the treatment of HIV and HBV with human serum albumin (HSA) is investigated. • The drug bound to HSA by hydrophobic force and induced some conformational changes in HSA. • The study of molecular docking showed that adefovir dipivoxil could bind to the site III of HSA mainly

Molecular modeling and multispectroscopic studies of the interaction of hepatitis B drug, adefovir dipivoxil with human serum albumin

Energy Technology Data Exchange (ETDEWEB)

Shahabadi, Nahid, E-mail: nahidshahabadi@yahoo.com [Department of Chemistry, Faculty of Science, Razi University, Kermanshah (Iran, Islamic Republic of); Medical Biology Research Center (MBRC) Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Falsafi, Monireh [Department of Chemistry, Faculty of Science, Razi University, Kermanshah (Iran, Islamic Republic of); Hadidi, Saba [Department of Chemistry, Faculty of Science, Razi University, Kermanshah (Iran, Islamic Republic of); Medical Biology Research Center (MBRC) Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of)

2015-11-15

The interaction of hepatitis B drug, adefovir dipivoxil with human serum albumin (HSA) was studied by using UV–vis, fluorometric, circular dichroism (CD) and molecular docking techniques. The results indicated that the binding of the drug to HSA caused fluorescence quenching through static quenching mechanism with binding constant of 1.3×103 M{sup −1}. The thermodynamic parameters indicated that the hydrophobic force contacts are the major forces in the stability of protein-drug complex (ΔH>0 and ΔS>0). The displacement experiments using the site probes viz., warfarin and ibuprofen showed that adefovir dipivoxil could bind to the site III of HSA. The results of CD and UV–vis spectroscopy indicated that the binding of the drug induced some conformational changes in HSA. Furthermore, the study of molecular docking also confirmed binding of adefovir dipivoxil to the site III of HSA by hydrophobic interaction. - Highlights: • The interaction of adefovir dipivoxil, drug for the treatment of HIV and HBV with human serum albumin (HSA) is investigated. • The drug bound to HSA by hydrophobic force and induced some conformational changes in HSA. • The study of molecular docking showed that adefovir dipivoxil could bind to the site III of HSA mainly.

Interactions of human serum albumin with doxorubicin in different media

Science.gov (United States)

Gun'ko, Vladimir M.; Turov, Vladimir V.; Krupska, Tetyana V.; Tsapko, Magdalina D.

2017-02-01

Interactions of human serum albumin (10 wt% H2O and 0.3 wt% sodium caprylate) with doxorubicin hydrochloride (1 wt%) were studied alone or with addition of HCl (3.6 wt% HCl) using 1H NMR spectroscopy. A model of hydrated HSA/12DOX was calculated using PM7 method with COSMO showing large variations in the binding constant depending on structural features of DOX/HSA complexes. DOX molecules/ions displace bound water from narrow intramolecular voids in HSA that leads to diminution of freezing-melting point depression of strongly bound water (SBW). Structure of weakly bound water (WBW) depends much weaker on the presence of DOX than SBW because a major fraction of DOX is bound to adsorption sites of HSA. Addition of HCl results in strong changes in structure of macromolecules and organization of water in hydration shells of HSA (i.e., mainly SBW) and in the solution (i.e., WBW + non-bound bulk water).

Binding interaction of atorvastatin with bovine serum albumin: Spectroscopic methods and molecular docking

Science.gov (United States)

Wang, Qi; Huang, Chuan-ren; Jiang, Min; Zhu, Ying-yao; Wang, Jing; Chen, Jun; Shi, Jie-hua

2016-03-01

The interaction of atorvastatin with bovine serum albumin (BSA) was investigated using multi-spectroscopic methods and molecular docking technique for providing important insight into further elucidating the store and transport process of atorvastatin in the body and the mechanism of action and pharmacokinetics. The experimental results revealed that the fluorescence quenching mechanism of BSA induced atorvastatin was a combined dynamic and static quenching. The binding constant and number of binding site of atorvastatin with BSA under simulated physiological conditions (pH = 7.4) were 1.41 × 105 M- 1 and about 1 at 310 K, respectively. The values of the enthalpic change (ΔH0), entropic change (ΔS0) and Gibbs free energy (ΔG0) in the binding process of atorvastatin with BSA at 310 K were negative, suggesting that the binding process of atorvastatin and BSA was spontaneous and the main interaction forces were van der Waals force and hydrogen bonding interaction. Moreover, atorvastatin was bound into the subdomain IIA (site I) of BSA, resulting in a slight change of the conformation of BSA.

Displacement of Drugs from Human Serum Albumin: From Molecular Interactions to Clinical Significance.

Science.gov (United States)

Rimac, Hrvoje; Debeljak, Željko; Bojić, Mirza; Miller, Larisa

2017-01-01

Human serum albumin (HSA) is the most abundant protein in human serum. It has numerous functions, one of which is transport of small hydrophobic molecules, including drugs, toxins, nutrients, hormones and metabolites. HSA has the ability to interact with a wide variety of structurally different compounds. This promiscuous, nonspecific affinity can lead to sudden changes in concentrations caused by displacement, when two or more compounds compete for binding to the same molecular site. It is important to consider drug combinations and their binding to HSA when defining dosing regimens, as this can directly influence drug's free, active concentration in blood. In present paper we review drug interactions with potential for displacement from HSA, situations in which they are likely to occur and their clinical significance. We also offer guidelines in designing drugs with decreased binding to HSA. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Study of the interaction between mercury (II) and bovine serum albumin by spectroscopic methods.

Science.gov (United States)

Chunmei, Dai; Cunwei, Ji; Huixiang, Lan; Yuze, Song; Wei, Yang; Dan, Zheng

2014-03-01

Mercury is a significant environmental pollutant that originates from industry. Mercury will bind with albumin and destroy biological functions in humans if it enters the blood. In this paper, the interaction between mercury (II) and bovine serum albumin (BSA) was investigated in vitro by fluorescence, UV-Vis absorption and circular dichroism (CD) under simulated physiological conditions. This study proves that the probable quenching mechanism of BSA by mercury (II) was mainly static quenching due to the formation of a mercury (II)-BSA complex. The quenching constant K(a) and the corresponding thermodynamic parameters (ΔH, ΔS and ΔG) at four different temperatures were calculated by a modified Stern-Volmer equation and the van't Hoff equation, respectively. The results revealed that the interaction between mercury (II) and BSA was mainly enthalpy-driven and that hydrogen bonding and van der Waals forces played a major role in the reaction. The obtained data for binding sites of n approximately equal to 1 indicated that there was a single class of binding site for the BSA with mercury (II). The value of the distance r (3.55 nm), determined by Föster's non-radioactive energy transfer theory, suggested that the energy transfer from BSA to mercury (II) occurred with a high probability. The conformational investigation from synchronous fluorescence, CD spectroscopy and three-dimensional fluorescence showed that the presence of mercury (II) resulted in micro-environmental and conformational changes of the BSA molecules, which may be responsible for the toxicity of mercury (II) in vivo. Copyright © 2014 Elsevier B.V. All rights reserved.

Metal-ligand interactions

Science.gov (United States)

Ervin, Kent M.

Experimental studies of the interactions of small transition-metal cluster anions with carbonyl ligands are reviewed and compared with neutral and cationic clusters. Under thermal conditions, the reaction rates of transition-metal clusters with carbon monoxide are measured as a function of cluster size. Saturation limits for carbon monoxide addition can be related to the geometric structures of the clusters. Both energy-resolved threshold collision-induced dissociation experiments and time-resolved photodissociation experiments are used to measure metal-carbonyl binding energies. For platinum and palladium trimer anions, the carbonyl binding energies are assigned to different geometric binding sites. Platinum and palladium cluster anions catalyse the oxidation of carbon monoxide to carbon dioxide in a full catalytic cycle at thermal energies.

A combined spectroscopic and molecular docking study on site selective binding interaction of Toluidine blue O with Human and Bovine serum albumins

Energy Technology Data Exchange (ETDEWEB)

Selva Sharma, Arumugam [Department of Chemistry, Bharathiar University, Coimbatore 641046 (India); Anandakumar, Shanmugam [Department of Bioinformatics, Bharathiar University, Coimbatore 641046 (India); Ilanchelian, Malaichamy, E-mail: chelian73@yahoo.com [Department of Chemistry, Bharathiar University, Coimbatore 641046 (India)

2014-07-01

In the present investigation the interaction of a biologically active photodynamic therapeutic agent Toluidine blue O (TBO) with Serum albumins viz Human serum albumin (HSA) and Bovine serum albumin (BSA) was studied using absorption, emission, circular dichroism spectroscopy and molecular docking experiments. The emission titration experiments between HSA/BSA and TBO revealed the existence of strong interactions between TBO and the proteins. The site competitive experiment of HSA and BSA showed that the primary binding site of TBO is located in site I of HSA/BSA involving hydrophobic, hydrogen bonding and electrostatic interaction. To ascertain the results of site competitive experiments, molecular docking was utilized to characterize the binding models of TBO–HSA/BSA complexes. From the molecular docking studies, free energy calculations were undertaken to examine the energy contributions and the role of various amino acid residues of HSA/BSA in TBO binding. The existence of Forster Resonance Energy Transfer (FRET) between the ligand and the protein was utilized to calculate the donor–acceptor distance of TBO and protein. The TBO induced conformational changes of HSA/BSA was established using synchronous emission, three dimensional emission and circular dichroism studies. - Highlights: • Site selective binding interaction of TBO with HSA and BSA were investigated. • TBO quenches the intrinsic fluorescence of HSA/BSA by static quenching process. • Computational studies of TBO with HSA/BSA substantiate the experimental findings. • 3D and CD spectral studies of TBO–HSA/BSA revealed structural changes in protein. • The distance (r) between TBO and HSA/BSA were estimated from FRET theory.

Phenytoin-Bovine Serum Albumin interactions - modeling plasma protein - drug binding: A multi-spectroscopy and in silico-based correlation

Science.gov (United States)

Suresh, P. K.; Divya, Naik; Nidhi, Shah; Rajasekaran, R.

2018-03-01

The study focused on the analysis of the nature and site of binding of Phenytoin (PHT) -(a model hydrophobic drug) with Bovine Serum Albumin (BSA) (a model protein used as a surrogate for HSA). Interactions with defined amounts of Phenytoin and BSA demonstrated a blue shift (hypsochromic -change in the microenvironment of the tryptophan residue with decrease in the polar environment and more of hydrophobicity) with respect to the albumin protein and a red shift (bathochromic -hydrophobicity and polarity related changes) in the case of the model hydrophobic drug. This shift, albeit lower in magnitude, has been substantiated by a fairly convincing, Phenytoin-mediated quenching of the endogenous fluorophore in BSA. Spectral shifts studied at varying pH, temperatures and incubation periods (at varying concentrations of PHT with a defined/constant BSA concentration) showed no significant differences (data not shown). FTIR analysis provided evidence of the interaction of PHT with BSA with a stretching vibration of 1737.86 cm- 1, apart from the vibrations characteristically associated with the amine and carboxyl groups respectively. Our in vitro findings were extended to molecular docking of BSA with PHT (with the different ionized forms of the drug) and the subsequent LIGPLOT-based analysis. In general, a preponderance of hydrophobic interactions was observed. These hydrophobic interactions corroborate the tryptophan-based spectral shifts and the fluorescence quenching data. These results substantiates our hitherto unreported in vitro/in silico experimental flow and provides a basis for screening other hydrophobic drugs in its class.

Molecular interaction of PCB153 to human serum albumin: Insights from spectroscopic and molecular modeling studies

Energy Technology Data Exchange (ETDEWEB)

Han, Chao; Fang, Senbiao; Cao, Huiming; Lu, Yan; Ma, Yaqiong [School of Pharmacy, Lanzhou University, Lanzhou 730000 (China); Wei, Dongfeng [Institute of Basic Research in Clinical Medicine, China Academy of Chinese Medical Sciences, Beijing 100700 (China); Xie, Xiaoyun [College of Earth and Environmental Science, Lanzhou University, Lanzhou 730000 (China); Liu, Xiaohua [School of Pharmacy, Lanzhou University, Lanzhou 730000 (China); Li, Xin [College of Food and Bioengineering, Henan University of Science and Technology, Luoyang 471003 (China); Fei, Dongqing [School of Pharmacy, Lanzhou University, Lanzhou 730000 (China); Zhao, Chunyan, E-mail: zhaochy07@lzu.edu.cn [School of Pharmacy, Lanzhou University, Lanzhou 730000 (China)

2013-03-15

Highlights: ► We identify the binding mode of PCB153 to human serum albumin (HSA). ► Spectroscopic and molecular modeling results reveal that PCB153 binds at the site II. ► The interaction is mainly governed by hydrophobic and hydrogen bond forces. ► The work helps to probe transporting, distribution and toxicity effect of PCBs. -- Abstract: Polychlorinated biphenyls (PCBs) possessed much potential hazard to environment because of its chemical stability and biological toxicity. Here, we identified the binding mode of a representative compound, PCB153, to human serum albumin (HSA) using fluorescence and molecular dynamics simulation methods. The fluorescence study showed that the intrinsic fluorescence of HSA was quenched by addition of PCB153 through a static quenching mechanism. The thermodynamic analysis proved the binding behavior was mainly governed by hydrophobic force. Furthermore, as evidenced by site marker displacement experiments using two probe compounds, it revealed that PCB153 acted exactly on subdomain IIIA (site II) of HSA. On the other hand, the molecular dynamics studies as well as free energy calculations made another important contribution to understand the conformational changes of HSA and the stability of HSA-PCB153 system. Molecular docking revealed PCB153 can bind in a large hydrophobic activity of subdomain IIIA by the hydrophobic interaction and hydrogen bond interactions between chlorine atoms and residue ASN391. The present work provided reasonable models helping us further understand the transporting, distribution and toxicity effect of PCBs when it spread into human blood serum.

The investigation of the interaction between NCP-EDA and bovine serum albumin by spectroscopic approaches

Science.gov (United States)

Yu, Xianyong; Lu, Shiyu; Yang, Ying; Li, Xiaofang; Yi, Pinggui

2011-12-01

The fluorescence and ultraviolet spectroscopies were explored to study the interaction between N-confused porphyrins-edaravone diad (NCP-EDA) and bovine serum albumin (BSA) under simulative physiological condition at different temperatures. The experimental results show that the fluorescence quenching mechanism between NCP-EDA and BSA is a combined quenching (dynamic and static quenching). The binding constants, binding sites and the corresponding thermodynamic parameters (Δ G, Δ H, and Δ S) of the interaction system were calculated at different temperatures. According to Förster non-radiation energy transfer theory, the binding distance between NCP-EDA and BSA was calculated to be 3.63 nm. In addition, the effect of NCP-EDA on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy.

Species dependence of [64Cu]Cu-Bis(thiosemicarbazone) radiopharmaceutical binding to serum albumins

International Nuclear Information System (INIS)

Basken, Nathan E.; Mathias, Carla J.; Lipka, Alexander E.; Green, Mark A.

2008-01-01

Introduction: Interactions of three copper(II) bis(thiosemicarbazone) positron emission tomography radiopharmaceuticals with human serum albumin, and the serum albumins of four additional mammalian species, were evaluated. Methods: 64 Cu-labeled diacetyl bis(N 4 -methylthiosemicarbazonato)copper(II) (Cu-ATSM), pyruvaldehyde bis(N 4 -methylthiosemicarbazonato)copper(II) (Cu-PTSM) and ethylglyoxal bis(thiosemicarbazonato)copper(II) (Cu-ETS) were synthesized and their binding to human, canine, rat, baboon and porcine serum albumins quantified by ultrafiltration. Protein binding was also measured for each tracer in human, porcine, rat and mouse serum. Results: The interaction of these neutral, lipophilic copper chelates with serum albumin is highly compound- and species-dependent. Cu-PTSM and Cu-ATSM exhibit particularly high affinity for human serum albumin (HSA), while the albumin binding of Cu-ETS is relatively insensitive to species. At HSA concentrations of 40 mg/ml, '% free' (non-albumin-bound) levels of radiopharmaceutical were 4.0±0.1%, 5.3±0.2% and 38.6±0.8% for Cu-PTSM, Cu-ATSM and Cu-ETS, respectively. Conclusions: Species-dependent variations in radiopharmaceutical binding to serum albumin may need to be considered when using animal models to predict the distribution and kinetics of these compounds in humans

Study the interaction between CdTe-glutathione and human serum albumin

International Nuclear Information System (INIS)

Yang, Qing; Zhou, Xi-min; Zhu, Yi-shuo; Chen, Xing-guo

2013-01-01

In this paper, glutathione (GSH) modified CdTe quantum dots (CdTe-GSH QDs) were synthesized in an aqueous solution. Then, the binding of the CdTe-GSH QDs to human serum albumin (HSA) was studied using the fluorescence spectroscopy. The quenching mechanism was investigated in terms of the association constants and basic thermodynamic parameters. The fluorescence data revealed that CdTe-GSH QDs could quench the intrinsic fluorescence of human serum albumin by a static quenching mechanism. Furthermore, alteration of the secondary protein structure in the presence of the QDs was confirmed by synchronous fluorescence spectra. - Highlights: ► In this paper, the binding of the CdTe-GSH QDs to human serum albumin (HSA) was studied using a fluorescence spectroscopy. ► The quenching mechanism was investigated in terms of the association constants and basic thermodynamic parameters. ► Furthermore, alteration of the secondary protein structure in the presence of the QDs was confirmed by synchronous fluorescence spectra. ► The research can help us assess biological toxicity of QDs and further expand the application scope of QDs.

Probing the interaction of a new synthesized CdTe quantum dots with human serum albumin and bovine serum albumin by spectroscopic methods

Energy Technology Data Exchange (ETDEWEB)

Bardajee, Ghasem Rezanejade, E-mail: rezanejad@pnu.ac.ir; Hooshyar, Zari

2016-05-01

A novel CdTe quantum dots (QDs) were prepared in aqueous phase via a facile method. At first, poly (acrylic amide) grafted onto sodium alginate (PAAm-g-SA) were successfully synthesized and then TGA capped CdTe QDs (CdTe-TGA QDs) were embed into it. The prepared CdTe-PAAm-g-SA QDs were optimized and characterized by transmission electron microscopy (TEM), thermo-gravimetric (TG) analysis, Fourier transform infrared (FT-IR), UV–vis and fluorescence spectroscopy. The characterization results indicated that CdTe-TGA QDs, with particles size of 2.90 nm, were uniformly dispersed on the chains of PAAm-g-SA biopolymer. CdTe-PAAm-g-SA QDs also exhibited excellent UV–vis absorption and high fluorescence intensity. To explore biological behavior of CdTe-PAAm-g-SA QDs, the interactions between CdTe-PAAm-g-SA QDs and human serum albumin (HSA) (or bovine serum albumin (BSA)) were investigated by cyclic voltammetry, FT-IR, UV–vis, and fluorescence spectroscopic. The results confirmed the formation of CdTe-PAAm-g-SA QDs-HSA (or BSA) complex with high binding affinities. The thermodynamic parameters (ΔG < 0, ΔH < 0 and ΔS < 0) were indicated that binding reaction was spontaneous and van der Waals interactions and hydrogen-bond interactions played a major role in stabilizing the CdTe-PAAm-g-SA QDs-HSA (or BSA) complexes. The binding distance between CdTe-PAAm-g-SA QDs and HSA (or BSA)) was calculated about 1.37 nm and 1.27 nm, respectively, according to Forster non-radiative energy transfer theory (FRET). Analyzing FT-IR spectra showed that the formation of QDs-HSA and QDs-BSA complexes led to conformational changes of the HSA and BSA proteins. All these experimental results clarified the effective transportation and elimination of CdTe-PAAm-g-SA QDs in the body by binding to HSA and BSA, which could be a useful guideline for the estimation of QDs as a drug carrier. - Highlights: • The CdTe quantum dots coated with polyacrylamide grafted onto sodium alginate. • The

Interaction of diuron to human serum albumin: Insights from spectroscopic and molecular docking studies.

Science.gov (United States)

Chen, Huilun; Rao, Honghao; Yang, Jian; Qiao, Yongxiang; Wang, Fei; Yao, Jun

2016-01-01

This investigation was undertaken to determine the interaction of diuron with human serum albumin (HSA) was studied by monitoring the spectral behavior of diuron-HSA system. The fluorescence of HSA at 340 nm excited at 230 nm was obviously quenched by diuron due to dynamic collision and the quenching constant was of the order of 10(4) L mol(-1) at 310 K. However, no fluorescence quenching was observed when excited at 280 nm. Thermodynamic investigations revealed that the combination between diuron and HSA was entropy driven by predominantly hydrophobic interactions. The binding of diuron induced the drastic reduction in α-helix conformation and the significant enhancement in β-turn conformation of HSA. In addition, both sites marker competition study and molecular modeling simulation evidenced the binding of diuron to HSA primarily took place in subdomain IIIA (Sudlow's site II).

Climate change driven plant-metal-microbe interactions.

Science.gov (United States)

Rajkumar, Mani; Prasad, Majeti Narasimha Vara; Swaminathan, Sandhya; Freitas, Helena

2013-03-01

Various biotic and abiotic stress factors affect the growth and productivity of crop plants. Particularly, the climatic and/or heavy metal stress influence various processes including growth, physiology, biochemistry, and yield of crops. Climatic changes particularly the elevated atmospheric CO₂ enhance the biomass production and metal accumulation in plants and help plants to support greater microbial populations and/or protect the microorganisms against the impacts of heavy metals. Besides, the indirect effects of climatic change (e.g., changes in the function and structure of plant roots and diversity and activity of rhizosphere microbes) would lead to altered metal bioavailability in soils and concomitantly affect plant growth. However, the effects of warming, drought or combined climatic stress on plant growth and metal accumulation vary substantially across physico-chemico-biological properties of the environment (e.g., soil pH, heavy metal type and its bio-available concentrations, microbial diversity, and interactive effects of climatic factors) and plant used. Overall, direct and/or indirect effects of climate change on heavy metal mobility in soils may further hinder the ability of plants to adapt and make them more susceptible to stress. Here, we review and discuss how the climatic parameters including atmospheric CO₂, temperature and drought influence the plant-metal interaction in polluted soils. Other aspects including the effects of climate change and heavy metals on plant-microbe interaction, heavy metal phytoremediation and safety of food and feed are also discussed. This review shows that predicting how plant-metal interaction responds to altering climatic change is critical to select suitable crop plants that would be able to produce more yields and tolerate multi-stress conditions without accumulating toxic heavy metals for future food security. Copyright © 2012 Elsevier Ltd. All rights reserved.

Study on the interaction between tabersonine and human serum albumin by optical spectroscopy and molecular modeling methods

Energy Technology Data Exchange (ETDEWEB)

Jiang Hua; Chen, Rongrong [Department of Biology, College of Life Science and Technology, Jinan University, Guangzhou 510632 (China); Pu Hanlin, E-mail: tphl@jnu.edu.cn [Department of Biology, College of Life Science and Technology, Jinan University, Guangzhou 510632 (China)

2012-03-15

The mechanism of interaction between tabersonine (TAB) and human serum albumin (HSA) was investigated by the methods of fluorescence spectroscopy, UV-vis absorption spectroscopy and molecular modeling under simulative physiological conditions. Results obtained from analysis of fluorescence spectrum and fluorescence intensity indicated that TAB has a strong ability to quench the intrinsic fluorescence of HSA through a static quenching procedure. The binding site number n and apparent binding constant K{sub a}, corresponding thermodynamic parameters {Delta}G, {Delta}H and {Delta}S at different temperatures were calculated. The distance r between donor (human serum albumin) and acceptor (tabersonine) was obtained according to the Foerster theory of non-radiation energy transfer. The effect of common ions on binding constant was also investigated. The synchronous fluorescence and three-dimensional fluorescence spectra were used to investigate the structural change of HSA molecules with addition of TAB. Furthermore, the study of molecular modeling indicated that TAB could bind to the site I of HSA and hydrophobic interaction was the major acting force, which was in agreement with the binding mode study. - Highlights: Black-Right-Pointing-Pointer Fluorescence study of the mechanism of interaction between tabersonine and HSA. Black-Right-Pointing-Pointer The binding parameters and thermodynamic parameters were calculated. Black-Right-Pointing-Pointer The distance r was obtained and common ions effects was investigated. Black-Right-Pointing-Pointer Conformation of HSA and its molecular modeling was analyzed.

The role of nanoparticles in the albumin-cytarabine and albumin-methotrexate interactions

Energy Technology Data Exchange (ETDEWEB)

Pentak, Danuta, E-mail: danuta.pentak@us.edu.pl [Department of Materials Chemistry and Chemical Technology, Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice (Poland); Maciążek-Jurczyk, Małgorzata; Zawada, Zygmunt H. [School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, Medical University of Silesia, Department of Physical Pharmacy, Jagiellońska 4, 41-200 Sosnowiec (Poland)

2017-04-01

Understanding the interactions which occur between nanomaterials and biomolecules is one of the most important issues in nanotechnology. Determining the properties of nanoparticles obtained through the use of novel methods and defining the scope of their application as drug carriers has important practical significance. Nanoparticles containing methotrexate and cytarabine obtained by a modified reverse-phase evaporation method (mREV) were characterized through the use of the UV/Vis and NMR methods. Obtained results confirmed high degree of analysed drugs encapsulation. The encapsulation efficiencies of cytarabine (AraC) and methotrexate (MTX) in L{sub DPPC/AraC/MTX} were found to be 86.30% (AraC) and 86.00% (MTX). The increased permeability of the phospholipid membranes, resulting from physico-chemical properties and the location of the drug, as well as from the physico-chemical properties of the phospholipids themselves, has been confirmed by increase in the length of the T1 relaxation time of protons in the −N{sup +}(CH{sub 3}){sub 3} group. The study of analysed drugs release process from the liposomes has been made for bovine serum albumin, both in the absence (dBSA) and in the presence of fatty acid (BSA). Moreover two types of kinetic models (Bhaskar equation and Rigter-Peppas equation) have been used. Based on the study it has been concluded that mathematical modelling of drug release can be very helpful in speeding up product development and in better understanding the mechanisms controlling drug release from advanced delivery systems. - Graphical abstract: In vitro drug release profiles of different liposomal formulation. - Highlights: • Liposomes containing tested drugs can be obtained by mREV method. • High degree of encapsulation characterizes obtained liposomes. • Cytarabine and methotrexate release from liposomes followed both: diffusion and controlled mechanisms.

Investigation of interaction between alkoxy substituted phthalocyanines with different lengths of alkyl residue and bovine serum albumin

Energy Technology Data Exchange (ETDEWEB)

Lebedeva, Natalya Sh., E-mail: nsl@isc-ras.ru [G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, Akademicheskaya, 1, 153045 Ivanovo (Russian Federation); Gubarev, Yury A.; Vyugin, Anatoly I. [G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, Akademicheskaya, 1, 153045 Ivanovo (Russian Federation); Koifman, Oscar I. [Research Institute of Macroheterocycles of Ivanovo State University of Chemistry and Technology, 153000 Ivanovo (Russian Federation)

2015-10-15

Interaction between bovine serum albumin and alkoxy substituted phthalocyanines was studied by means of electron absorption spectroscopy, fluorescence spectroscopy and viscosimetry. The binding constants and binding distance were calculated. It was found that ZnPc(4-NH-CO-C{sub 6}H{sub 4}-OC{sub 10}H{sub 21}){sub 4} prevents twisting of BSA molecule and localizes between subdomains IB and IIA in protein globule. ZnPc(4-NH-CO-C{sub 6}H{sub 4}-OC{sub 6}H{sub 13}){sub 4} and ZnPc(4-NH-CO-C{sub 6}H{sub 4}-OC{sub 8}H{sub 17}){sub 4} are located on the outer surface of the protein globule. In the case of ZnPc(4-NH-CO-C{sub 6}H{sub 4}-OC{sub 3}H{sub 7}){sub 4} it can be assumed that the phthalocyanine molecule is in the immediate vicinity of the subdomains IB and IIA. - Highlights: • Interaction between bovine serum albumin and alkoxy substituted phthalocyanines was studied by means of electron absorption spectroscopy, fluorescence spectroscopy and viscosimetry. • The binding constants and binding distance were calculated by using the Scatchard method. • Photochemical characteristics of phthalocyanines of studied phthalocyanines are defined. • Localization of phthalocyanines on the protein globule is defined.

Spin-exchange interaction between transition metals and metalloids in soft-ferromagnetic metallic glasses

Science.gov (United States)

Das, Santanu; Choudhary, Kamal; Chernatynskiy, Aleksandr; Choi Yim, Haein; Bandyopadhyay, Asis K.; Mukherjee, Sundeep

2016-06-01

High-performance magnetic materials have immense industrial and scientific importance in wide-ranging electronic, electromechanical, and medical device technologies. Metallic glasses with a fully amorphous structure are particularly suited for advanced soft-magnetic applications. However, fundamental scientific understanding is lacking for the spin-exchange interaction between metal and metalloid atoms, which typically constitute a metallic glass. Using an integrated experimental and molecular dynamics approach, we demonstrate the mechanism of electron interaction between transition metals and metalloids. Spin-exchange interactions were investigated for a Fe-Co metallic glass system of composition [(Co1-x Fe x )0.75B0.2Si0.05]96Cr4. The saturation magnetization increased with higher Fe concentration, but the trend significantly deviated from simple rule of mixtures. Ab initio molecular dynamics simulation was used to identify the ferromagnetic/anti-ferromagnetic interaction between the transition metals and metalloids. The overlapping band-structure and density of states represent ‘Stoner type’ magnetization for the amorphous alloys in contrast to ‘Heisenberg type’ in crystalline iron. The enhancement of magnetization by increasing iron was attributed to the interaction between Fe 3d and B 2p bands, which was further validated by valence-band study.

Luminescence quenching by heavy metal ions of probes based on anthracene, pyrene, and eosin in human serum albumin

Science.gov (United States)

Naumova, E. V.; Melnikov, A. G.; Melnikov, G. V.

2013-05-01

Fluorescence and phosphorescence quenching processes of polar and non-polar luminescent probes associated with human serum albumin (HSA) in phosphate buffer at pH 7.4 were studied. Stern-Volmer quenching constants of anthracene and pyrene fluorescence and eosin phosphorescence and rate constants for quenching of eosin triplet states were determined. The polarity index of pyrene bound to HSA was obtained as a function of thallium nitrate concentration. The influences of structural changes in the proteins that were stimulated by heavy-metal salts and of screening of protein charges by salt ions on quenching processes of singlet and triplet states of the probes were found.

SPECTROPHOTOMETRIC ANALYSIS OF BOVINE SERUM ALBUMIN IN PRESENCE OF SOME BISCHALCONES

OpenAIRE

Shweta Garg; Mamta Singh; N. Raghav

2013-01-01

We have synthesized a series of bischalcones by the Claisen-Schmidt condensation and their effect was observed on bovine serum albumin. We have found that the synthesized bischalcones interacted with bovine serum albumin irrespective of the nature and position of the substituent with a little difference.

Study the interaction between CdTe-glutathione and human serum albumin

Energy Technology Data Exchange (ETDEWEB)

Yang, Qing; Zhou, Xi-min; Zhu, Yi-shuo [National Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000 (China); Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Chen, Xing-guo, E-mail: chenxg@lzu.edu.cn [National Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000 (China); Department of Chemistry, Lanzhou University, Lanzhou 730000 (China)

2013-03-15

In this paper, glutathione (GSH) modified CdTe quantum dots (CdTe-GSH QDs) were synthesized in an aqueous solution. Then, the binding of the CdTe-GSH QDs to human serum albumin (HSA) was studied using the fluorescence spectroscopy. The quenching mechanism was investigated in terms of the association constants and basic thermodynamic parameters. The fluorescence data revealed that CdTe-GSH QDs could quench the intrinsic fluorescence of human serum albumin by a static quenching mechanism. Furthermore, alteration of the secondary protein structure in the presence of the QDs was confirmed by synchronous fluorescence spectra. - Highlights: Black-Right-Pointing-Pointer In this paper, the binding of the CdTe-GSH QDs to human serum albumin (HSA) was studied using a fluorescence spectroscopy. Black-Right-Pointing-Pointer The quenching mechanism was investigated in terms of the association constants and basic thermodynamic parameters. Black-Right-Pointing-Pointer Furthermore, alteration of the secondary protein structure in the presence of the QDs was confirmed by synchronous fluorescence spectra. Black-Right-Pointing-Pointer The research can help us assess biological toxicity of QDs and further expand the application scope of QDs.

Diketo modification of curcumin affects its interaction with human serum albumin

Science.gov (United States)

Shaikh, Shaukat Ali M.; Singh, Beena G.; Barik, Atanu; Ramani, Modukuri V.; Balaji, Neduri V.; Subbaraju, Gottumukkala V.; Naik, Devidas B.; Indira Priyadarsini, K.

2018-06-01

Curcumin isoxazole (CI) and Curcumin pyrazole (CP), the diketo modified derivatives of Curcumin (CU) are metabolically more stable and are being explored for pharmacological properties. One of the requirements in such activities is their interaction with circulatory proteins like human serum albumin (HSA). To understand this, the interactions of CI and CP with HSA have been investigated employing absorption and fluorescence spectroscopy and the results are compared with that of CU. The respective binding constants of CP, CI and CU with HSA were estimated to be 9.3 × 105, 8.4 × 105 and 2.5 × 105 M-1, which decreased with increasing salt concentration in the medium. The extent of decrease in the binding constant was the highest in CP followed by CI and CU. This revealed that along with hydrophobic interaction other binding modes like electrostatic interactions operate between CP/CI/CU with HSA. Fluorescence quenching studies of HSA with these compounds suggested that both static and dynamic quenching mechanisms operate, where the contribution of static quenching is higher for CP and CI than that for CU. From fluorescence resonance energy transfer studies, the binding site of CU, CI and CP was found to be in domain IIA of HSA. CU was found to bind in closer proximity with Trp214 as compared to CI and CP and the same was responsible for efficient energy transfer and the same was also established by fluorescence anisotropy measurements. Furthermore docking simulation complemented the experimental observation, where both electrostatic as well as hydrophobic interactions were indicated between HSA and CP, CI and CU. This study is useful in designing more stable CU derivatives having suitable binding properties with proteins like HSA.

Diketo modification of curcumin affects its interaction with human serum albumin.

Science.gov (United States)

Shaikh, Shaukat Ali M; Singh, Beena G; Barik, Atanu; Ramani, Modukuri V; Balaji, Neduri V; Subbaraju, Gottumukkala V; Naik, Devidas B; Indira Priyadarsini, K

2018-06-15

Curcumin isoxazole (CI) and Curcumin pyrazole (CP), the diketo modified derivatives of Curcumin (CU) are metabolically more stable and are being explored for pharmacological properties. One of the requirements in such activities is their interaction with circulatory proteins like human serum albumin (HSA). To understand this, the interactions of CI and CP with HSA have been investigated employing absorption and fluorescence spectroscopy and the results are compared with that of CU. The respective binding constants of CP, CI and CU with HSA were estimated to be 9.3×10 5 , 8.4×10 5 and 2.5×10 5 M -1 , which decreased with increasing salt concentration in the medium. The extent of decrease in the binding constant was the highest in CP followed by CI and CU. This revealed that along with hydrophobic interaction other binding modes like electrostatic interactions operate between CP/CI/CU with HSA. Fluorescence quenching studies of HSA with these compounds suggested that both static and dynamic quenching mechanisms operate, where the contribution of static quenching is higher for CP and CI than that for CU. From fluorescence resonance energy transfer studies, the binding site of CU, CI and CP was found to be in domain IIA of HSA. CU was found to bind in closer proximity with Trp214 as compared to CI and CP and the same was responsible for efficient energy transfer and the same was also established by fluorescence anisotropy measurements. Furthermore docking simulation complemented the experimental observation, where both electrostatic as well as hydrophobic interactions were indicated between HSA and CP, CI and CU. This study is useful in designing more stable CU derivatives having suitable binding properties with proteins like HSA. Copyright © 2018 Elsevier B.V. All rights reserved.

Profile of total protein, albumin, globulin and albumin globulin ratio in bulls

Directory of Open Access Journals (Sweden)

Ida Zahidah Irfan

2014-06-01

Full Text Available Determination of serum total protein concentration and main fractions (albumin and globulin can be used as an important diagnostic tool in clinical biochemistry. Several factors can affect the concentration of total protein, albumin, globulin and albumin globulin ratio (A/G. The aim of this study is to obtain serum protein profiles, albumin, globulin and A/G ratio based on breed, age and BCS (body condition score. Blood samples from 160 bulls were collected. Blood chemistry were analyzed by photometer principle using a commercial kit. There were significant (P<0.001 breed variation on total protein, albumin, globulin and albumin globulin ratio. Significant age differences were observed on total protein and albumin concentration (P<0.001, while globulin concentration and A/G ratio were also significant (P<0.05. Amongs groups of BCS, significant difference was verified only in the albumin concentration (P<0.05. The concentration of total proteins, albumins and globulins in the serum of the bulls are higher than standard values for cattle, while A/G ratio is lower.

Species dependence of [{sup 64}Cu]Cu-Bis(thiosemicarbazone) radiopharmaceutical binding to serum albumins

Energy Technology Data Exchange (ETDEWEB)

Basken, Nathan E. [Division of Nuclear Pharmacy, Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, IN 47907 (United States)], E-mail: nbasken@purdue.edu; Mathias, Carla J. [Division of Nuclear Pharmacy, Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, IN 47907 (United States); Lipka, Alexander E. [Department of Statistics, Purdue University, West Lafayette, IN 47907 (United States); Green, Mark A. [Division of Nuclear Pharmacy, Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, IN 47907 (United States)], E-mail: magreen@purdue.edu

2008-04-15

Introduction: Interactions of three copper(II) bis(thiosemicarbazone) positron emission tomography radiopharmaceuticals with human serum albumin, and the serum albumins of four additional mammalian species, were evaluated. Methods: {sup 64}Cu-labeled diacetyl bis(N{sup 4}-methylthiosemicarbazonato)copper(II) (Cu-ATSM), pyruvaldehyde bis(N{sup 4}-methylthiosemicarbazonato)copper(II) (Cu-PTSM) and ethylglyoxal bis(thiosemicarbazonato)copper(II) (Cu-ETS) were synthesized and their binding to human, canine, rat, baboon and porcine serum albumins quantified by ultrafiltration. Protein binding was also measured for each tracer in human, porcine, rat and mouse serum. Results: The interaction of these neutral, lipophilic copper chelates with serum albumin is highly compound- and species-dependent. Cu-PTSM and Cu-ATSM exhibit particularly high affinity for human serum albumin (HSA), while the albumin binding of Cu-ETS is relatively insensitive to species. At HSA concentrations of 40 mg/ml, '% free' (non-albumin-bound) levels of radiopharmaceutical were 4.0{+-}0.1%, 5.3{+-}0.2% and 38.6{+-}0.8% for Cu-PTSM, Cu-ATSM and Cu-ETS, respectively. Conclusions: Species-dependent variations in radiopharmaceutical binding to serum albumin may need to be considered when using animal models to predict the distribution and kinetics of these compounds in humans.

Activation volume and interaction of metal particulate media

Energy Technology Data Exchange (ETDEWEB)

Tetsukawa, Hiroki [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan)]. E-mail: tetsukaw@arc.sony.co.jp; Kondo, Hirofumi [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan)

2005-09-15

We have investigated the activation volume (V{sub ac}) and magnetostatic interaction of metal particulate (MP) media. The activation volume of MP media decreases with the decrease of physical volume (V{sub phy}) of metal particles. The activation volume and the ratio of V{sub phy}/V{sub ac} of advanced metal particles are 6x10{sup -24}m{sup 3} and 1.5, respectively. It can be predicted that the physical volume of metal particle is about 3x10{sup -24}m{sup 3} when the physical volume is equal to the activation volume. This value is agreement with the practical lower limit of physical volume of metal particle predicted by Sharrock. The negative interaction (demagnetization effect) in MP media decreases with low saturation magnetization of the metal particles, a thin magnetic layer, a high orientation of MP media, and a low packing fraction of metal particles in the MP media. The activation volume of the MP media decreased as the negative interactions decreased. In advanced MP media with low M{sub r}.t (M{sub r}=remanent magnetization and t=thickness), the influence of interaction on the activation volume is reduced.

Activation volume and interaction of metal particulate media

International Nuclear Information System (INIS)

Tetsukawa, Hiroki; Kondo, Hirofumi

2005-01-01

We have investigated the activation volume (V ac ) and magnetostatic interaction of metal particulate (MP) media. The activation volume of MP media decreases with the decrease of physical volume (V phy ) of metal particles. The activation volume and the ratio of V phy /V ac of advanced metal particles are 6x10 -24 m 3 and 1.5, respectively. It can be predicted that the physical volume of metal particle is about 3x10 -24 m 3 when the physical volume is equal to the activation volume. This value is agreement with the practical lower limit of physical volume of metal particle predicted by Sharrock. The negative interaction (demagnetization effect) in MP media decreases with low saturation magnetization of the metal particles, a thin magnetic layer, a high orientation of MP media, and a low packing fraction of metal particles in the MP media. The activation volume of the MP media decreased as the negative interactions decreased. In advanced MP media with low M r .t (M r =remanent magnetization and t=thickness), the influence of interaction on the activation volume is reduced

Albumin microaggregates for radioactive scanning of reticuloendothelial systems

International Nuclear Information System (INIS)

Saklad, E.L.

1980-01-01

An agent is described for radioactively imaging the reticuloendothelial system (RES) of vertebrates, especially primates, particularly the liver, spleen and bone marrow. The RES agent consists of a sup(99m)Tc-labelled microaggregated complex of a reducing metal and albumin to the unlabelled microaggregated complex in the form of a kit. The agent may also contain a stabilizing ligand for the reducing metal, e.g. a phosphonate, phosphate, aminocarboxylate, polyhydroxycarboxylate or polycarboxylates. The methods of preparing the agent and using it for RES imaging are described. (U.K.)

Controlling adsorption of albumin with hyaluronan on silica surfaces and sulfonated latex particles.

Science.gov (United States)

Berts, Ida; Fragneto, Giovanna; Porcar, Lionel; Hellsing, Maja S; Rennie, Adrian R

2017-10-15

Polysaccharides are known to modify binding of proteins at interfaces and this paper describes studies of these interactions and how they are modified by pH. Specifically, the adsorption of human serum albumin on to polystyrene latex and to silica is described, focusing on how this is affected by hyaluronan. Experiments were designed to test how such binding might be modified under relevant physiological conditions. Changes in adsorption of albumin alone and the co-adsorption of albumin and hyaluronan are driven by electrostatic interactions. Multilayer binding is found to be regulated by the pH of the solution and the molecular mass and concentration of hyaluronan. Highest adsorption was observed at pH below 4.8 and for low molecular mass hyaluronan (≤150kDa) at concentrations above 2mgml -1 . On silica with grafted hyaluronan, albumin absorption is reversed by changes in solvent pH due to their strong electrostatic attraction. Albumin physisorbed on silica surfaces is also rinsed away with dilute hyaluronan solution at pH 4.8. The results demonstrate that the protein adsorption can be controlled both by changes of pH and by interaction with other biological macromolecules. Copyright © 2017 Elsevier Inc. All rights reserved.

Interaction of different thiol-capped CdTe quantum dots with bovine serum albumin

International Nuclear Information System (INIS)

Wang Qisui; Zhang Xiaolei; Zhou Xiaolan; Fang Tingting; Liu Pengfei; Liu Peng; Min Xinmin; Li, Xi

2012-01-01

Due to their unique optical properties, quantum dots (QDs) are rapidly revolutionizing many areas of medicine and biology. Despite the remarkable speed of development of nanoscience, relatively little is known about the interaction of nanoscale objects with organism. In this work, interaction of CdTe QDs coated with mercaptopropanoic acid (MPA), L-cysteine (L-cys), and glutathione (GSH) with bovine serum albumin (BSA) was investigated. Fluorescence (FL), UV–vis absorption, and circular dichroism (CD) spectra methods were used. The Stern-Volmer quenching constant (K sv ) at different temperatures, corresponding thermodynamic parameters (ΔH, ΔG and ΔS), and information of the structural features of BSA were gained. We found that QDs can effectively quench the FL of BSA in a ligand-dependent manner, electrostatic interactions play a major role in the binding reaction, and the nature of quenching is static, resulting in forming QDs-BSA complexes. The CD spectra showed that the secondary and tertiary structure of BSA was changed. This study contributes to a better understanding of the ligand effects on QDs-proteins interactions, which is a critical issue for the applications in vivo. - Highlights: ► The interaction between three thiol-capped QDs and BSA by UV–vis, FL, and CD spectra. ► The bio-effect of CdTe QDs on BSA was a ligand-dependent manner. ► The thermodynamic parameters and the structural features of BSA were gained.

Study of albumin from beef blood serum in D2O solutions

International Nuclear Information System (INIS)

Lewandowska, D.; Podoski, T.

1994-01-01

Molecular dynamics of albumin obtained from beef blood serum have been investigated in heavy water solutions by means of NMR spectra. The chemical shifts as well as spin-lattice relaxation times have been measured. The number of water protons interacting with albumin molecule have been estimated

Metal-microorganism interactions

International Nuclear Information System (INIS)

Andres, Y.; Thouand, G.; Redercher, S.; Boualam, M.; Texier, A.Cl.; Hoeffer, R.

1997-01-01

The physico-chemical procedures of treating the metalliferous effluents are not always adapted to de polluting the slightly concentrated industrial wastes. An alternative idea was advanced, implying the ability of some microorganisms to fix in considerable amounts the metal ions present in aqueous solutions, possibly in a selective way. This approach has been investigated thoroughly during the last 30 years, particularly from a mechanistic point of view. The advantage of the microorganisms lies mainly in the large diversity of bacteria and in their chemical state dependent interaction with metals, as well as, in the possibilities of developing their selective and quantitative separation properties. A biomass from Mycobacterium smegmatis, an acidic alcoholic resistant bacteria, has been used to prepare a bio-sorption support allowing the preferential sorption of thorium as compared to uranium and lanthanum. These studies have been extended to biological polymers such as chitosan and to studies related to bioaccumulation mechanisms and/or to the microbial resistances towards metals

Interaction of singlet oxygen with bovine serum albumin and the role of the protein nano-compartmentalization.

Science.gov (United States)

Giménez, Rodrigo E; Vargová, Veronika; Rey, Valentina; Turbay, M Beatriz Espeche; Abatedaga, Inés; Morán Vieyra, Faustino E; Paz Zanini, Verónica I; Mecchia Ortiz, Juan H; Katz, Néstor E; Ostatná, Veronika; Borsarelli, Claudio D

2016-05-01

Singlet molecular oxygen ((1)O2) contributes to protein damage triggering biophysical and biochemical changes that can be related with aging and oxidative stress. Serum albumins, such as bovine serum albumin (BSA), are abundant proteins in blood plasma with different biological functions. This paper presents a kinetic and spectroscopic study of the (1)O2-mediated oxidation of BSA using the tris(2,2'-bipyridine)ruthenium(II) cation [Ru(bpy)3](2+) as sensitizer. BSA quenches efficiently (1)O2 with a total (chemical+physical interaction) rate constant kt(BSA)=7.3(±0.4)×10(8)M(-1)s(-1), where the chemical pathway represented 37% of the interaction. This efficient quenching by BSA indicates the participation of several reactive residues. MALDI-TOF MS analysis of intact BSA confirmed that after oxidation by (1)O2, the mass protein increased the equivalent of 13 oxygen atoms. Time-resolved emission spectra analysis of BSA established that Trp residues were oxidized to N'-formylkynurenine, being the solvent-accessible W134 preferentially oxidized by (1)O2 as compared with the buried W213. MS confirmed oxidation of at least two Tyr residues to form dihydroxyphenylalanine, with a global reactivity towards (1)O2 six-times lower than for Trp residues. Despite the lack of MS evidences, kinetic and chemical analysis also suggested that residues other than Trp and Tyr, e.g. Met, must react with (1)O2. Modeling of the 3D-structure of BSA indicated that the oxidation pattern involves a random distribution of (1)O2 into BSA; allowing also the interaction of (1)O2 with buried residues by its diffusion from the bulk solvent through interconnected internal hydrophilic and hydrophobic grooves. Copyright © 2016 Elsevier Inc. All rights reserved.

Interaction of spermine with DNA, vitamin C and bovine serum albumin in the unirradiated and gamma irradiated states

International Nuclear Information System (INIS)

Upadhyay, S.N.; Lal, C.; Bhardwaj, R.; Chaturvedi, S.; Chaudhury, N.K.

2006-01-01

Structural deformability of spermine with radiation dose (maximum 10 Gy) has been proved. Complex formation of spermine with DNA, vitamin C and BSA took place. Calibration and radiation-induced absorption changes in spermine by ninhydrin reagent has been followed quantitatively. Interaction of vitamin C with DNA and their radiation-induced changes have been reported. Interaction of spermine with DNA in the unirradiated and gamma irradiated states in 10 -3 M phosphate buffer and water have been compared. Addition of spermine and vitamin C to DNA makes DNA structure more condensed. Bovine serum albumin also binds with spermine and protects it from radiation-induced degradation. (author)

Spectroscopic study of the interaction of styrylcyanine dyes Sbo, Sil and their derivatives with bovine serum albumin.

Science.gov (United States)

Kurtaliev, Eldar N

2011-07-01

The spectral-luminescent characteristics of newly synthesized styrylcyanine dyes on the base of dyes Sbo ((E)-2-(4-(dimethylamino)styryl)-3-methylbenzo[d]oxazol-3-ium iodide) and Sil ((E)-2-(4-(dimethylamino)styryl)-1,3,3-trimethyl-3H-indolium perchlorate) in aqueous solutions without and in the presence of bovine serum albumin (BSA) were studied. It was established that the absorption spectra of dyes Tol-6, Dbo-10 and Dil-10 with increasing amount of BSA appear new bands with λ(max)=505 nm, λ(max)=512 nm and λ(max)=566 nm, respectively, whose intensity increases in proportion to the amount of albumin. The intensity of the glow of the main band of fluorescence in the presence of BSA sharply increases. The binding constant (K) and the number of binding sites (N) of studied dyes with BSA were determined. The dependence of binding constants with BSA on the dipole moment of dye molecules was determined, which indicates that besides electrostatic forces of attraction between molecules styrylcyanine dyes with BSA, hydrophobic interactions are essential. © Springer Science+Business Media, LLC 2011

Multispectroscopic and molecular modeling approach to investigate the interaction of diclofop-methyl enantiomers with human serum albumin

Energy Technology Data Exchange (ETDEWEB)

Zhang, Ping; Liu, Donghui; Li, Zhe; Shen, Zhigang; Wang, Peng [Department of Applied Chemistry, China Agricultural University, Beijing 100193 (China); Zhou, Meng [Business School, University of Bedfordshire, Luton LU1 3JU (United Kingdom); Zhou, Zhiqiang [Department of Applied Chemistry, China Agricultural University, Beijing 100193 (China); Zhu, Wentao, E-mail: wentaozhu@cau.edu.cn [Department of Applied Chemistry, China Agricultural University, Beijing 100193 (China)

2014-11-15

Pesticides and related environmental contaminants have always been threated to human health due to their intrinsic toxicity. In the context of this contribution, the interaction between diclofop-methyl (DM) enantiomers and human serum albumin (HSA) has been characterized by steady state and three-dimensional fluorescence, molecular modeling, circular dichroism (CD) and ultraviolet–visible (UV–vis) spectroscopy. The binding constants significantly showed the binding was enantioselective and HSA had higher affinity for S-DM. The thermodynamic parameters of the binding reaction (ΔG, ΔH and ΔS) clearly signified that hydrophobic effects and H-bonds contribute to the formation of DM-HSA complex. The alterations of protein secondary structure in the presence of DM enantiomers were confirmed by CD spectroscopy, UV–vis and three-dimensional fluorescence spectroscopy. In addition, both fluorescence probe study and molecular modeling simulation evidenced the binding of DM enantiomers to HSA primarily took place in subdomain IIIA (Sudlow's site II). This investigation highlights the binding mechanism, specific binding sites and binding region of DM enantiomers on human serum albumin at the first time. Besides, such task can provide important insight to the interaction of the physiological protein HSA with chiral aryloxyphenoxypropionate herbicides and give support to the human health risk assessment. - Highlights: • The binding of DM enantiomers to HSA was enantioselective. • HSA had higher affinity for S-DM than R-DM. • Hydrophobic effects and hydrogen bonds were involved in the DM-HSA interaction. • The binding of DM enantiomers to HSA primarily took place in Sudlow's site II. • DM enantiomers could alter the second structure of HSA.

Multispectroscopic and molecular modeling approach to investigate the interaction of diclofop-methyl enantiomers with human serum albumin

International Nuclear Information System (INIS)

Zhang, Ping; Liu, Donghui; Li, Zhe; Shen, Zhigang; Wang, Peng; Zhou, Meng; Zhou, Zhiqiang; Zhu, Wentao

2014-01-01

Pesticides and related environmental contaminants have always been threated to human health due to their intrinsic toxicity. In the context of this contribution, the interaction between diclofop-methyl (DM) enantiomers and human serum albumin (HSA) has been characterized by steady state and three-dimensional fluorescence, molecular modeling, circular dichroism (CD) and ultraviolet–visible (UV–vis) spectroscopy. The binding constants significantly showed the binding was enantioselective and HSA had higher affinity for S-DM. The thermodynamic parameters of the binding reaction (ΔG, ΔH and ΔS) clearly signified that hydrophobic effects and H-bonds contribute to the formation of DM-HSA complex. The alterations of protein secondary structure in the presence of DM enantiomers were confirmed by CD spectroscopy, UV–vis and three-dimensional fluorescence spectroscopy. In addition, both fluorescence probe study and molecular modeling simulation evidenced the binding of DM enantiomers to HSA primarily took place in subdomain IIIA (Sudlow's site II). This investigation highlights the binding mechanism, specific binding sites and binding region of DM enantiomers on human serum albumin at the first time. Besides, such task can provide important insight to the interaction of the physiological protein HSA with chiral aryloxyphenoxypropionate herbicides and give support to the human health risk assessment. - Highlights: • The binding of DM enantiomers to HSA was enantioselective. • HSA had higher affinity for S-DM than R-DM. • Hydrophobic effects and hydrogen bonds were involved in the DM-HSA interaction. • The binding of DM enantiomers to HSA primarily took place in Sudlow's site II. • DM enantiomers could alter the second structure of HSA

Cu(II) bis(thiosemicarbazone) radiopharmaceutical binding to serum albumin: further definition of species dependence and associated substituent effects

International Nuclear Information System (INIS)

Basken, Nathan E.; Green, Mark A.

2009-01-01

Introduction: The pyruvaldehyde bis(N 4 -methylthiosemicarbazonato)copper(II) (Cu-PTSM) and diacetyl bis(N 4 -methylthiosemicarbazonato)copper(II) (Cu-ATSM) radiopharmaceuticals exhibit strong, species-dependent binding to the IIA site of human serum albumin (HSA), while the related ethylglyoxal bis(thiosemicarbazonato)copper(II) (Cu-ETS) radiopharmaceutical appears to exhibit only nonspecific binding to HSA and animal serum albumins. Methods: To further probe the structural basis for the species dependence of this albumin binding interaction, we examined protein binding of these three radiopharmaceuticals in solutions of albumin and/or serum from a broader array of mammalian species (rat, sheep, donkey, rabbit, cow, pig, dog, baboon, mouse, cat and elephant). We also evaluated the albumin binding of several copper(II) bis(thiosemicarbazone) chelates offering more diverse substitution of the ligand backbone. Results: Cu-PTSM and Cu-ATSM exhibit a strong interaction with HSA that is not apparent with the albumins of other species, while the binding of Cu-ETS to albumin is much less species dependent. The strong interaction of Cu-PTSM with HSA does not appear to simply correlate with variation, relative to the animal albumins, of a single amino acid lining HSA's IIA site. Those agents that selectively interact with HSA share the common feature of only methyl or hydrogen substitution at the carbon atoms of the diimine fragment of the ligand backbone. Conclusions: The interspecies variations in albumin binding of Cu-PTSM and Cu-ATSM are not simply explained by unique amino acid substitutions in the IIA binding pocket of the serum albumins. However, the specific affinity for this region of HSA is disrupted when substituents bulkier than a methyl group appear on the imine carbons of the copper bis(thiosemicarbazone) chelate.

Cu(II) bis(thiosemicarbazone) radiopharmaceutical binding to serum albumin: further definition of species dependence and associated substituent effects

Energy Technology Data Exchange (ETDEWEB)

Basken, Nathan E. [Division of Nuclear Pharmacy, Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, IN 47907 (United States); Green, Mark A. [Division of Nuclear Pharmacy, Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, IN 47907 (United States)], E-mail: magreen@purdue.edu

2009-07-15

Introduction: The pyruvaldehyde bis(N{sup 4}-methylthiosemicarbazonato)copper(II) (Cu-PTSM) and diacetyl bis(N{sup 4}-methylthiosemicarbazonato)copper(II) (Cu-ATSM) radiopharmaceuticals exhibit strong, species-dependent binding to the IIA site of human serum albumin (HSA), while the related ethylglyoxal bis(thiosemicarbazonato)copper(II) (Cu-ETS) radiopharmaceutical appears to exhibit only nonspecific binding to HSA and animal serum albumins. Methods: To further probe the structural basis for the species dependence of this albumin binding interaction, we examined protein binding of these three radiopharmaceuticals in solutions of albumin and/or serum from a broader array of mammalian species (rat, sheep, donkey, rabbit, cow, pig, dog, baboon, mouse, cat and elephant). We also evaluated the albumin binding of several copper(II) bis(thiosemicarbazone) chelates offering more diverse substitution of the ligand backbone. Results: Cu-PTSM and Cu-ATSM exhibit a strong interaction with HSA that is not apparent with the albumins of other species, while the binding of Cu-ETS to albumin is much less species dependent. The strong interaction of Cu-PTSM with HSA does not appear to simply correlate with variation, relative to the animal albumins, of a single amino acid lining HSA's IIA site. Those agents that selectively interact with HSA share the common feature of only methyl or hydrogen substitution at the carbon atoms of the diimine fragment of the ligand backbone. Conclusions: The interspecies variations in albumin binding of Cu-PTSM and Cu-ATSM are not simply explained by unique amino acid substitutions in the IIA binding pocket of the serum albumins. However, the specific affinity for this region of HSA is disrupted when substituents bulkier than a methyl group appear on the imine carbons of the copper bis(thiosemicarbazone) chelate.

Characteristics and thermodynamics of the interaction of 6-shogaol with human serum albumin as studied by isothermal titration calorimetry

Directory of Open Access Journals (Sweden)

Shevin Rizal Feroz

Full Text Available ABSTRACT The interaction between 6-shogaol, a pharmacologically active ginger constituent, and human serum albumin (HSA, the main in vivo drug transporter, was investigated using isothermal titration calorimetry (ITC. The value of the binding constant, Ka (5.02 ± 1.37 × 104 M−1 obtained for the 6-shogaol-HSA system suggested intermediate affinity. Analysis of the ITC data revealed feasibility of the binding reaction due to favorable enthalpy and entropy changes. The values of the thermodynamic parameters suggested involvement of van der Waals forces, hydrogen bonds and hydrophobic interactions in the 6-shogaol-HSA complex formation.

Investigation of the Interaction Between Human Serum Albumin and Two Drugs as Binary and Ternary Systems.

Science.gov (United States)

Abdollahpour, Nooshin; Soheili, Vahid; Saberi, Mohammad Reza; Chamani, Jamshidkhan

2016-12-01

Human serum albumin (HSA) is the most frequent protein in blood plasma. Albumin transports various compounds, preserves osmotic pressure, and buffers pH. A unique feature of albumin is its ability to bind drugs and other bioactive molecules. However, it is important to consider binary and ternary systems of two pharmaceuticals to estimate the effect of the first drug on the second one and physicochemical properties. Different techniques including time-resolved, second-derivative and anisotropy fluorescence spectroscopy, resonance light scattering (RLS), critical induced aggregation concentration (C CIAC ), particle size, zeta potential and stability analysis were employed in this assessment to elucidate the binding behavior of Amlodipine and Aspirin to HSA. Moreover, isothermal titration calorimetric techniques were performed and the QSAR properties were applied to analyze the hydration energy and log P. Multiple sequence alignments were also used to predict the structure and biological characteristics of the HSA binding site. Time-resolved fluorescence spectroscopy showed interaction of both drugs to HSA based on a static quenching mechanism. Subsequently, second-derivative fluorescence spectroscopy presented different values of parameter H in binary and ternary systems, which were suggested that tryptophan was in a more polar environment in the ternary system than in a binary system. Moreover, the polydispersity index and results from mean number measurements revealed that the presence of the second drug caused a decrease in the stability of systems and increased the heterogeneity of complex. It is also, observed that the gradual addition of HSA has led to a marked increase in fluorescence anisotropy (r) of Amlodipine and Aspirin which can be suggested that the drugs were located in a restricted environment of the protein as confirmed by Red Edge Excitation Shift (REES) studies. The isothermal titration calorimetric technique demonstrated that the interaction of

Long-range interactions among three alkali-metal atoms

International Nuclear Information System (INIS)

Marinescu, M.; Starace, A.F.

1996-01-01

The long-range asymptotic form of the interaction potential surface for three neutral alkali-metal atoms in their ground states may be expressed as an expansion in inverse powers of inter-nuclear distances. The first leading powers are proportional to the dispersion coefficients for pairwise atomic interactions. They are followed by a term responsible for a three body dipole interaction. The authors results consist in evaluation of the three body dipole interaction coefficient between three alkali-metal atoms. The generalization to long-range n atom interaction terms will be discussed qualitatively

Surface/structure functionalization of copper-based catalysts by metal-support and/or metal-metal interactions

Science.gov (United States)

Konsolakis, Michalis; Ioakeimidis, Zisis

2014-11-01

Cu-based catalysts have recently attracted great attention both in catalysis and electro-catalysis fields due to their excellent catalytic performance and low cost. Given that their performance is determined, to a great extent, by Cu sites local environment, considerable efforts have been devoted on the strategic modifications of the electronic and structural properties of Cu sites. In this regard, the feasibility of tuning the local structure of Cu entities by means of metal-support or metal-metal interactions is investigated. More specifically, the physicochemical properties of Cu entities are modified by employing: (i) different oxides (CeO2, La2O3, Sm2O3), or (ii) ceria-based mixed oxides (Ce1-xSmxOδ) as supporting carriers, and (iii) a second metal (Cobalt) adjacent to Cu (bimetallic Cu-Co/CeO2). A characterization study, involving BET, XRD, TPR, and XPS, reveal that significant modifications on structural, redox and electronic properties of Cu sites can be induced by adopting either different oxide carriers or bimetallic complexes. Fundamental insights into the tuning of Cu local environment by metal-support or metal-metal interactions are provided, paving the way for real-life industrial applications.

Interactions of poly(amidoamine) dendrimers with human serum albumin: binding constants and mechanisms.

Science.gov (United States)

Giri, Jyotsnendu; Diallo, Mamadou S; Simpson, André J; Liu, Yi; Goddard, William A; Kumar, Rajeev; Woods, Gwen C

2011-05-24

The interactions of nanomaterials with plasma proteins have a significant impact on their in vivo transport and fate in biological fluids. This article discusses the binding of human serum albumin (HSA) to poly(amidoamine) [PAMAM] dendrimers. We use protein-coated silica particles to measure the HSA binding constants (K(b)) of a homologous series of 19 PAMAM dendrimers in aqueous solutions at physiological pH (7.4) as a function of dendrimer generation, terminal group, and core chemistry. To gain insight into the mechanisms of HSA binding to PAMAM dendrimers, we combined (1)H NMR, saturation transfer difference (STD) NMR, and NMR diffusion ordered spectroscopy (DOSY) of dendrimer-HSA complexes with atomistic molecular dynamics (MD) simulations of dendrimer conformation in aqueous solutions. The binding measurements show that the HSA binding constants (K(b)) of PAMAM dendrimers depend on dendrimer size and terminal group chemistry. The NMR (1)H and DOSY experiments indicate that the interactions between HSA and PAMAM dendrimers are relatively weak. The (1)H NMR STD experiments and MD simulations suggest that the inner shell protons of the dendrimers groups interact more strongly with HSA proteins. These interactions, which are consistently observed for different dendrimer generations (G0-NH(2)vs G4-NH(2)) and terminal groups (G4-NH(2)vs G4-OH with amidoethanol groups), suggest that PAMAM dendrimers adopt backfolded configurations as they form weak complexes with HSA proteins in aqueous solutions at physiological pH (7.4).

Species Differences in the Binding of Sodium 4-Phenylbutyrate to Serum Albumin.

Science.gov (United States)

Yamasaki, Keishi; Enokida, Taisuke; Taguchi, Kazuaki; Miyamura, Shigeyuki; Kawai, Akito; Miyamoto, Shuichi; Maruyama, Toru; Seo, Hakaru; Otagiri, Masaki

2017-09-01

Sodium 4-phenylbutyrate (PB) is clinically used as a drug for treating urea cycle disorders. Recent research has shown that PB also has other pharmacologic activities, suggesting that it has the potential for use as a drug for treating other disorders. In the process of drug development, preclinical testing using experimental animals is necessary to verify the efficacy and safety of PB. Although the binding of PB to human albumin has been studied, our knowledge of its binding to albumin from the other animal species is extremely limited. To address this issue, we characterized the binding of PB to albumin from several species (human, bovine, rabbit, and rat). The results indicated that PB interacts with 1 high-affinity site of albumin from these species, which corresponds to site II of human albumin. The affinities of PB to human and bovine albumins were higher than those to rabbit and rat albumin, and that to rabbit albumin was the lowest. Binding and molecular docking studies using structurally related compounds of PB suggested that species differences in the affinity are attributed to differences in the structural feature of the PB-binding sites on albumins (e.g., charge distribution, hydrophobicity, shape, or size). Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Selective analysis of human serum albumin based on SEC-ICP-MS after labelling with iophenoxic acid

DEFF Research Database (Denmark)

Dersch, Julie Maria; Nguyen, Tam T. T. N.; Østergaard, Jesper

2015-01-01

Human serum albumin (HSA) is the most abundant protein in the human plasma. HSA has several physiological roles in the human body, including storage and transport. Owing to the predominance of albumin in plasma, HSA is often involved in the protein binding of drugs. The aim of this work was to de...... plasma and urine samples and for studying the binding of cisplatin to proteins in the human plasma.......Human serum albumin (HSA) is the most abundant protein in the human plasma. HSA has several physiological roles in the human body, including storage and transport. Owing to the predominance of albumin in plasma, HSA is often involved in the protein binding of drugs. The aim of this work...... was to develop a selective, quantitative method for determining albumin in plasma with the purpose of clarifying the fate of metal-based drugs in biological systems. The method can also be applied for determination of urine albumin, which is of relevance in diagnostics of kidney disease. A selective method...

Ammonia nanotubes and their interactions with coinage metals

Energy Technology Data Exchange (ETDEWEB)

Mohajeri, Afshan, E-mail: amohajeri@shirazu.ac.ir; Bozorgizadeh, Tahereh

2014-09-30

Highlights: • The possibility of building ammonia nanotubes (ANTs) is explored. • Six ANTs formed by the stacks of 4- and 5-membered ammonia rings have been studied. • The interactions between the ANTs and coinage metals are investigated. • The nature of nitrogen–metal bonds is unveiled by quantum chemical approaches. - Abstract: The hydrogen bond networks of finite ammonia molecules are considered to explore the possibility of building ammonia nanotubes (ANTs). Six ANTs formed by the stacks of 4- and 5-membered ammonia rings have been studied. The calculated stabilization energies indicate considerable stability for ANTs. In the second part, the interactions between the constructed ANTs and coinage metals (M = Cu, Ag, and Au) are investigated with a focus on the nature of nitrogen…metal bonds. The changes in binding energies from copper to gold reveal that the three metals have almost similar tendency for the interaction with ANTs and the interaction strength is governed by the structure of ANT. Furthermore, the electronic and structural properties of the resulting complexes have been unveiled by means of the quantum chemical analyses. The N…M bonds are found to have partially covalent and partially electrostatic nature.

Trace Metal Requirements and Interactions in Symbiodinium kawagutii

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Irene B. Rodriguez

2018-02-01

Full Text Available Photosynthetic organisms need trace metals for various biological processes and different groups of microalgae have distinctive obligate necessities due to their respective biochemical requirements and ecological niches. We have previously shown that the dinoflagellate Symbiodinium kawagutii requires high concentrations of bioavailable Fe to achieve optimum growth. Here, we further explored the trace metal requirements of S. kawagutii with intensive focus on the effect of individual metal and its interaction with other divalent metals. We found that low Zn availability significantly decreases growth rates and results in elevated intracellular Mn, Co, Ni, and Fe quotas in the dinoflagellate. The results highlight the complex interaction among trace metals in S. kawagutii and suggest either metal replacement strategy to counter low Zn availability or enhanced uptake of other metals by non-specific divalent metal transporters. In this work, we also examined the Fe requirement of S. kawagutii using continuous cultures. We validated that 500 pM of Fe′ was sufficient to support maximum cell density during steady state growth period either at 26 or 28°C. This study shows that growth of S. kawagutii was limited by metal availability in the following order, Fe > Zn > Mn > Cu > Ni > Co. The fundamental information obtained for the free-living Symbiodinium shall provide insights into how trace metal availability, either from ambient seawater or hosts, affects growth and proliferation of symbiotic dinoflagellates and the interaction between symbiont and their hosts.

Investigation on the interaction between bovine serum albumin and 2,2-diphenyl-1-picrylhydrazyl

Energy Technology Data Exchange (ETDEWEB)

Li, Xiangrong [Department of Chemistry, School of Basic Medicine, Xinxiang Medical University, Xinxiang, Henan 453003 (China); Chen, Dejun; Wang, Gongke [School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, 46 Jian-she Road, Mu Ye District, Xinxiang, Henan 453007 (China); Lu, Yan, E-mail: 1842457577@qq.com [School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, 46 Jian-she Road, Mu Ye District, Xinxiang, Henan 453007 (China)

2014-12-15

Albumin represents a very abundant and important circulating antioxidant in plasma. In this paper, the ability of bovine serum albumin (BSA) to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical has been investigated using UV–vis absorption spectra. The result shows that the antioxidant activity of BSA against DPPH radical is similar to glutathione and the value of IC{sub 50} is 5.153×10{sup −5} mol L{sup −1}. The interaction between BSA and DPPH has been investigated without or with the eight popular antioxidants (L-ascorbic acid, α-tocopherol, glutathione, melatonin, (+)-catechin hydrate, procyanidine B3, β-carotene and astaxanthin) by means of fluorescence spectroscopy and circular dichroism (CD) spectroscopy. The fluorescence experiments show that DPPH quenches the fluorescence intensity of BSA through a static mechanism. The quenching process of DPPH with BSA is easily affected by the eight antioxidants, however, they cannot change the quenching mechanism of DPPH with BSA. Additionally, as shown by synchronous fluorescence spectroscopy and CD, DPPH may induce conformational and microenvironmental changes of BSA. - Highlights: • The antioxidant activity of BSA against DPPH is similar to glutathione. • DPPH can quench the fluorescence of BSA through a static quenching. • One molecule of DPPH radical reduced by one molecule of BSA. • The eight antioxidants cannot change the quenching mechanism of DPPH with BSA. • The binding parameters are decreased by the introduction of the eight antioxidants.

Optical, structural and thermodynamic properties of the interaction between tradimefon and serum albumin

Science.gov (United States)

Zhang, Hua-xin; Mei, Ping; Yang, Xi-xiong

2009-04-01

The biological toxicity of a chloric pesticide, tradimefon to bovine serum albumin (BSA) were studied by fluorescence and absorption spectroscopy. The fluorescence quenching mechanism analysis indicates the quenching of BSA by TDF was caused by BSA-TDF complex formation and electrostatic interaction played major role in the reaction. The number of binding sites n and observed binding constant Kb was measured by fluorescence quenching method. The thermodynamic parameters Δ Hθ, Δ Gθ, Δ Sθ at different temperatures were calculated, and the distance r between donor (BSA) and acceptor (TDF) was obtained according to Förster theory of non-radiation energy transfer. Three-dimensional fluorescence spectra, circular dichroism (CD) spectra and synchronous fluorescence spectra were used to investigate the structural change of BSA molecules with addition of TDF and the mechanism of binding reaction was analyzed at molecular level.

Interaction of alkali metal nitrates with calcium carbonate and kyanite

International Nuclear Information System (INIS)

Protsyuk, A.P.; Malakhov, A.I.; Karabanov, V.P.; Lebedeva, L.P.

1978-01-01

Thermographic, thermodynamic and X-ray phase studies have been made into the interaction of alkali metal nitrates with calcium carbonate and kyanite. Examined among other things was the effect of water vapor and carbon dioxide on the interaction between alkali metal nitrates and kyanite. The chemical mechanism of the occurring processes has been established. The interaction with calcium carbonates results in the formation of alkali metal carbonates and calcium oxide with liberation of nitrogen oxide and oxygen. The products of the interaction with kyanite are shown to be identical with the compounds forming when alkali metal carbonates are used

Fluorescent bovine serum albumin interacting with the antitussive quencher dextromethorphan: a spectroscopic insight.

Science.gov (United States)

Durgannavar, Amar K; Patgar, Manjanath B; Nandibewoor, Sharanappa T; Chimatadar, Shivamurti A

2016-05-01

The interaction of dextromethorphan hydrobromide (DXM) with bovine serum albumin (BSA) is studied by using fluorescence spectra, UV-vis absorption, synchronous fluorescence spectra (SFS), 3D fluorescence spectra, Fourier transform infrared (FTIR) spectroscopy and circular dichroism under simulated physiological conditions. DXM effectively quenched the intrinsic fluorescence of BSA. Values of the binding constant, K(A), are 7.159 × 10(3), 9.398 × 10(3) and 16.101 × 10(3)  L/mol; the number of binding sites, n, and the corresponding thermodynamic parameters ΔG°, ΔH° and ΔS° between DXM and BSA were calculated at different temperatures. The interaction between DXM and BSA occurs through dynamic quenching and the effect of DXM on the conformation of BSA was analyzed using SFS. The average binding distance, r, between the donor (BSA) and acceptor (DXM) was determined based on Förster's theory. The results of fluorescence spectra, UV-vis absorption spectra and SFS show that the secondary structure of the protein has been changed in the presence of DXM. Copyright © 2015 John Wiley & Sons, Ltd.

Role played by Disabled-2 in albumin induced MAP Kinase signalling

International Nuclear Information System (INIS)

Diwakar, Ramaswamy; Pearson, Alexander L.; Colville-Nash, Paul; Baines, Deborah L.; Dockrell, Mark E.C.

2008-01-01

Albumin has been shown to activate the mitogen activated protein kinase (MAPK) pathway in proximal tubular cells (PTECs) of the kidney. Megalin, the putative receptor for albumin has potential signalling properties. However, the mechanisms by which megalin signals are unclear. The adaptor phosphoprotein Disabled-2 (Dab2) is known to interact with the cytoplasmic tail of megalin and may be involved in albumin-mediated MAPK signalling. In this study, we investigated the role of Dab2 in albumin-mediated MAPK signalling and further studied the role of Dab2 in albumin-induced TGFβ-1 secretion, a MAPK dependent event. We used RNA interference to knockdown Dab2 protein abundance in HKC-8 cells a model of human PTECs. Albumin activated ERK1,2 and Elk-1 in a MEK-1 dependent manner and resulted in secretion of TGFβ-1. In the absence of albumin, knockdown of Dab2 resulted in a trend towards increase in pERK1,2 consistent with its putative role as an inhibitor of cell proliferation. However albumin-induced ERK1,2 activation was completely abolished by Dab2 knockdown. Dab2 knockdown did not however result in inhibition of albumin-induced TGFβ-1 secretion. These results suggest that Dab2 is a ligand dependent bi-directional regulator of ERK1,2 activity by demonstrating that in addition to its more traditional role as an inhibitor of ERK1,2 it may also activate ERK1,2

Human serum albumin homeostasis: a new look at the roles of synthesis, catabolism, renal and gastrointestinal excretion, and the clinical value of serum albumin measurements

Directory of Open Access Journals (Sweden)

Levitt DG

2016-07-01

Full Text Available David G Levitt,1,* Michael D Levitt2,* 1Department of Integrative Biology and Physiology, University of Minnesota, 2Research Service, Veterans Affairs Medical Center, Minneapolis, MN, USA *These authors contributed equally to this work Abstract: Serum albumin concentration (CP is a remarkably strong prognostic indicator of morbidity and mortality in both sick and seemingly healthy subjects. Surprisingly, the specifics of the pathophysiology underlying the relationship between CP and ill-health are poorly understood. This review provides a summary that is not previously available in the literature, concerning how synthesis, catabolism, and renal and gastrointestinal clearance of albumin interact to bring about albumin homeostasis, with a focus on the clinical factors that influence this homeostasis. In normal humans, the albumin turnover time of about 25 days reflects a liver albumin synthesis rate of about 10.5 g/day balanced by renal (≈6%, gastrointestinal (≈10%, and catabolic (≈84% clearances. The acute development of hypoalbuminemia with sepsis or trauma results from increased albumin capillary permeability leading to redistribution of albumin from the vascular to interstitial space. The best understood mechanism of chronic hypoalbuminemia is the decreased albumin synthesis observed in liver disease. Decreased albumin production also accounts for hypoalbuminemia observed with a low-protein and normal caloric diet. However, a calorie- and protein-deficient diet does not reduce albumin synthesis and is not associated with hypoalbuminemia, and CP is not a useful marker of malnutrition. In most disease states other than liver disease, albumin synthesis is normal or increased, and hypoalbuminemia reflects an enhanced rate of albumin turnover resulting either from an increased rate of catabolism (a poorly understood phenomenon or enhanced loss of albumin into the urine (nephrosis or intestine (protein-losing enteropathy. The latter may occur

Biophysical study on the interaction of ceftriaxone sodium with bovine serum albumin using spectroscopic methods.

Science.gov (United States)

Pan, Jiongwei; Ye, Zaiting; Cai, Xiaoping; Wang, Liangxing; Cao, Zhuo

2012-12-01

The interaction of ceftriaxone sodium (CS), a cephalosporin antibiotic, with the major transport protein, bovine serum albumin (BSA), was investigated using different spectroscopic techniques such as fluorescence, circular dichroism (CD), and UV-vis spectroscopy. Values of binding parameters for BSA-CS interaction in terms of binding constant and number of binding sides were found to be 9.00 × 10(3), 3.24 × 10(3), and 2.30 × 10(3) M(-1) at 281, 301, and 321 K, respectively. Thermodynamic analysis of the binding data obtained at different temperatures showed that the binding process was spontaneous and was primarily mediated by van der Waals force or hydrogen bonding. CS binding to BSA caused secondary structural alterations in the protein as revealed by CD results. The distance between CS and Trp of BSA was determined as 3.23 nm according to the Förster resonance energy transfer theory. © 2012 Wiley Periodicals, Inc.

Hepatic bilirubin uptake in the isolated perfused rat liver is not facilitated by albumin binding

International Nuclear Information System (INIS)

Stollman, Y.R.; Gaertner, U.; Theilmann, L.; Ohmi, N.; Wolkoff, A.W.

1983-01-01

Bilirubin uptake by the liver has kinetic characteristics which suggest carrier-mediation. Bilirubin is readily bound to albumin. A liver cell surface receptor for albumin has been postulated. The present study was designed to examine directly whether albumin facilitates the hepatic uptake of bilirubin and whether uptake of bilirubin depends on binding to albumin. Rat liver was perfused with a protein-free fluorocarbon medium, and single-pass uptake of 1, 10, or 200 nmol of [ 3 H]bilirubin was determined after injection as an equimolar complex with 125 I-albumin, with 125 I-ligandin, or free with only a [ 14 C]sucrose reference. Uptake of 10 nmol of [ 3 H]bilirubin was 67.5 +/- 3.7% of the dose when injected with 125 I-albumin, 67.4 +/- 6.5% when injected with 125 I-ligandin, and 74.9 +/- 2.4% when injected with [ 14 C]sucrose (P greater than 0.1). At 200 nmol, uptake fell to 46.4 +/- 3.1% ( 125 I-albumin) and 63.3 +/- 3.4% [( 14 C]sucrose) of injected [ 3 H]bilirubin (P less than 0.01), which suggests saturation of the uptake mechanism. When influx was quantitated by the model of Goresky, similar results were obtained. When [ 3 H]bilirubin was injected simultaneously with equimolar 125 I-albumin and a [ 14 C]sucrose reference, there was no delay in 125 I-albumin transit as compared with that of [ 14 C]sucrose. This suggested that the off-rate of albumin from a putative hepatocyte receptor would have to be very rapid, which is unusual for high affinity receptor-ligand interaction. There was no evidence for facilitation of bilirubin uptake by binding to albumin or for interaction of albumin with a liver cell surface receptor. These results suggest that the hepatic bilirubin uptake mechanism is one of high affinity which can extract bilirubin from circulating carriers such as albumin, ligandin, or fluorocarbon

Combined spectroscopic and molecular docking techniques to study interaction of Zn (II) DiAmsar with serum albumins

Energy Technology Data Exchange (ETDEWEB)

Bardajee, Ghasem Rezanejade, E-mail: rezanejad@pnu.ac.ir; Hooshyar, Zari; Shafagh, Pegah; Ghiasvand, Samira; Kakavand, Nahaleh

2014-12-15

Zinc (II) diamine-sarcophagine (Zn (II) DiAmsar) as a water soluble hexadentate ligand was synthesized and characterized by nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR) and UV–visible (UV–vis) spectroscopy. The bindings of Zn (II) DiAmsar with human serum albumin (HSA) and bovine serum albumin (BSA) were investigated under the simulative physiological conditions. To study this binding, the fluorescence spectra in combination with FT-IR, UV–vis, cyclic voltammetry (CV), and molecular docking techniques were used in the present work. The results indicate that Zn (II) DiAmsar quenched effectively the intrinsic fluorescence of HSA and BSA via a static quenching process. The fluorescence quenching data was also used to determine binding sites and binding constants at different temperatures. The calculated thermodynamic parameters (∆G°, ∆H°, and ∆S°) suggest that the binding process occurs spontaneously by involving hydrogen bond and van der Waals interactions. The distance between HSA (or BSA) as a donor and Zn (II) DiAmsar as an acceptor was obtained according to fluorescence resonance energy transfer (FRET). In addition, the docking results revealed the possible binding sites and assess the microenvironment around the bounded Zn (II) DiAmsar.

Study of the interactions between fluoroquinolones and human serum albumin by affinity capillary electrophoresis and fluorescence method

International Nuclear Information System (INIS)

Zhang Liwei; Wang Kun; Zhang Xinxiang

2007-01-01

The interactions between fluoroquinolones and human serum albumin (HSA) were investigated by affinity capillary electrophoresis (ACE) and fluorescence quenching technique. Based on the efficient separation of several fluoroquinolones using a simple phosphate buffer, the binding constants of fluoroquinolones with HSA were determined simultaneously during one set of electrophoresis by ACE method. The thermodynamic parameters were obtained from data at different temperatures, and the negative ΔH and ΔS values showed that both hydrogen bonds and van der Waals interaction played major roles in the binding of fluoroquinolones to HSA. The interactions were also studied by fluorescence quenching technique. The results of fluorescence titration revealed that fluoroquinolones had the strong ability to quenching the intrinsic fluorescence of HSA through the static quenching procedure. The binding site number n, apparent binding constant K b and the Stern-Volmer quenching constant K sv were determined. The thermodynamic parameters were also studied by fluorescence method, and the results were consonant with that of ACE

Raman microspectroscopy of nanodiamond-induced structural changes in albumin.

Science.gov (United States)

Svetlakova, Anastasiya S; Brandt, Nikolay N; Priezzhev, Alexander V; Chikishev, Andrey Yu

2015-04-01

Nanodiamonds (NDs) are promising agents for theranostic applications due to reported low toxicity and high biocompatibility, which is still being extensively tested on cellular, tissue, and organism levels. It is presumed that for experimental and future clinical applications, NDs will be administered into the organism via the blood circulation system. In this regard, the interaction of NDs with blood components needs to be thoroughly studied. We studied the interaction of carboxylated NDs (cNDs) with albumin, one of the major proteins of blood plasma. After 2-h long in vitro incubation in an aqueous solution of the protein, 100-nm cNDs were dried and the dry samples were studied with the aid of Raman microspectroscopy. The spectroscopic data indicate significant conformational changes that can be due to cND–protein interaction. A possible decrease in the functional activity of albumin related to the conformational changes must be taken into account in the in vivo applications.

Raman microspectroscopy of nanodiamond-induced structural changes in albumin

Science.gov (United States)

Svetlakova, Anastasiya S.; Brandt, Nikolay N.; Priezzhev, Alexander V.; Chikishev, Andrey Yu.

2015-04-01

Nanodiamonds (NDs) are promising agents for theranostic applications due to reported low toxicity and high biocompatibility, which is still being extensively tested on cellular, tissue, and organism levels. It is presumed that for experimental and future clinical applications, NDs will be administered into the organism via the blood circulation system. In this regard, the interaction of NDs with blood components needs to be thoroughly studied. We studied the interaction of carboxylated NDs (cNDs) with albumin, one of the major proteins of blood plasma. After 2-h long in vitro incubation in an aqueous solution of the protein, 100-nm cNDs were dried and the dry samples were studied with the aid of Raman microspectroscopy. The spectroscopic data indicate significant conformational changes that can be due to cND-protein interaction. A possible decrease in the functional activity of albumin related to the conformational changes must be taken into account in the in vivo applications.

Induction of axial chirality in divanillin by interaction with bovine serum albumin.

Directory of Open Access Journals (Sweden)

Diego Venturini

Full Text Available Vanillin is a plant secondary metabolite and has numerous beneficial health applications. Divanillin is the homodimer of vanillin and used as a taste enhancer compound and also a promissory anticancer drug. Here, divanillin was synthesized and studied in the context of its interaction with bovine serum albumin (BSA. We found that divanillin acquires axial chirality when complexed with BSA. This chiroptical property was demonstrated by a strong induced circular dichroism (ICD signal. In agreement with this finding, the association constant between BSA and divanillin (3.3 x 105 mol-1L was higher compared to its precursor vanillin (7.3 x 104 mol-1L. The ICD signal was used for evaluation of the association constant, demonstration of the reversibility of the interaction and determination of the binding site, revealing that divanillin has preference for Sudlow's site I in BSA. This property was confirmed by displacement of the fluorescent markers warfarin (site I and dansyl-L-proline (site II. Molecular docking simulation confirmed the higher affinity of divanillin to site I. The highest scored conformation obtained by docking (dihedral angle 242° was used for calculation of the circular dichroism spectrum of divanillin using Time-Dependent Density Functional Theory (TDDFT. The theoretical spectrum showed good similarity with the experimental ICD. In summary, we have demonstrated that by interacting with the chiral cavities in BSA, divanillin became a atropos biphenyl, i.e., the free rotation around the single bound that links the aromatic rings was impeded. This phenomenon can be explained considering the interactions of divanillin with amino acid residues in the binding site of the protein. This chiroptical property can be very useful for studying the effects of divanillin in biological systems. Considering the potential pharmacological application of divanillin, these findings will be helpful for researchers interested in the pharmacological

Probing the interaction of human serum albumin with DPPH in the absence and presence of the eight antioxidants.

Science.gov (United States)

Li, Xiangrong; Chen, Dejun; Wang, Gongke; Lu, Yan

2015-02-25

Albumin represents a very abundant and important circulating antioxidant in plasma. DPPH radical is also called 2,2-diphenyl-1-picrylhydrazyl. It has been widely used for measuring the efficiency of antioxidants. In this paper, the ability of human serum albumin (HSA) to scavenge DPPH radical was investigated using UV-vis absorption spectra. The interaction between HSA and DPPH was investigated in the absence and presence of eight popular antioxidants using fluorescence spectroscopy. These results indicate the antioxidant activity of HSA against DPPH radical is similar to glutathione and the value of IC50 is 5.200×10(-5) mol L(-1). In addition, the fluorescence experiments indicate the quenching mechanism of HSA, by DPPH, is a static process. The quenching process of DPPH with HSA is easily affected by the eight antioxidants, however, they cannot change the quenching mechanism of DPPH with HSA. The binding of DPPH to HSA primarily takes place in subdomain IIA and exists two classes of binding sites with two different interaction behaviors. The decreased binding constants and the number of binding sites of DPPH with HSA by the introduction of the eight antioxidants may result from the competition of the eight antioxidants and DPPH binding to HSA. The binding of DPPH to HSA may induce the micro-environment of the lone Trp-214 from polar to slightly nonpolar. Copyright © 2014 Elsevier B.V. All rights reserved.

Metal-metal interaction mediates the iron induction of Drosophila MtnB

International Nuclear Information System (INIS)

Qiang, Wenjia; Huang, Yunpeng; Wan, Zhihui; Zhou, Bing

2017-01-01

Metallothionein (MT) protein families are a class of small and universal proteins rich in cysteine residues. They are synthesized in response to heavy metal stresses to sequester the toxic ions by metal-thiolate bridges. Five MT family members, namely MtnA, MtnB, MtnC, MtnD and MtnE, have been discovered and identified in Drosophila. These five isoforms of MTs are regulated by metal responsive transcription factor dMTF-1 and play differentiated but overlapping roles in detoxification of metal ions. Previous researches have shown that Drosophila MtnB responds to copper (Cu), cadmium (Cd) and zinc (Zn). Interestingly in this study we found that Drosophila MtnB expression also responds to elevated iron levels in the diet. Further investigations revealed that MtnB plays limited roles in iron detoxification, and the direct binding of MtnB to ferrous iron in vitro is also weak. The induction of MtnB by iron turns out to be mediated by iron interference of other metals, because EDTA at even a partial concentration of that of iron can suppress this induction. Indeed, in the presence of iron, zinc homeostasis is altered, as reflected by expression changes of zinc transporters dZIP1 and dZnT1. Thus, iron-mediated MtnB induction appears resulting from interrupted homeostasis of other metals such as zinc, which in turns induced MtnB expression. Metal-metal interaction may more widely exist than we expected. - Highlights: • Metallothionein B expression is regulated by iron in Drosophila melanogaster. • MtnB has limited physiological roles in iron detoxification. • Binding affinity of MtnB to iron is weak in vitro. • Induction of Drosophila MtnB by iron is mediated indirectly through metal-metal interaction.

He–He and He–metal interactions in transition metals from first-principles

Energy Technology Data Exchange (ETDEWEB)

Zhang, Pengbo, E-mail: zhangpb@dlmu.edu.cn [Department of Physics, Dalian Maritime University, Dalian 116026 (China); Zou, Tingting [Information Science and Technology College, Dalian Maritime University, Dalian 116026 (China); Zhao, Jijun, E-mail: zhaojj@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China)

2015-12-15

We investigated the atomistic mechanism of He–He and He–metal interactions in bcc transition metals (V, Nb, Ta, Cr, Mo, W, and Fe) using first-principles methods. We calculated formation energy and binding energy of He–He pair as function of distance within the host lattices. The strengths of He–He attraction in Cr, Mo, W, and Fe (0.37–1.11 eV) are significantly stronger than those in V, Nb, and Ta (0.06–0.17 eV). Such strong attractions mean that He atoms would spontaneously aggregate inside perfect Cr, Mo, W, and Fe host lattices in absence of defects like vacancies. The most stable configuration of He–He pair is <100> dumbbell in groups VB metals, whereas it adopts close <110> configuration in Cr, Mo, and Fe, and close <111> configuration in W. Overall speaking, the He–He equilibrium distances of 1.51–1.55 Å in the group VIB metals are shorter than 1.65–1.70 Å in the group VB metals. Moreover, the presence of interstitial He significantly facilitates vacancy formation and this effect is more pronounced in the group VIB metals. The present calculations help understand the He-metal/He–He interaction mechanism and make a prediction that He is easier to form He cluster and bubbles in the groups VIB metals and Fe.

Spectroscopic study on interaction between bisphenol A or its degraded solution under microwave irradiation in the presence of activated carbon and human serum albumin

International Nuclear Information System (INIS)

Zhang Zhaohong; Xu Danping; Tie Mei; Li Fangyi; Chen Zhonglin; Wang Jie; Gao Wei; Ji Xiaotong; Xu Yao

2011-01-01

In this study, the interaction between bisphenol A (BPA) or its degraded solution under microwave irradiation after their adsorption on activated carbon (AC/MW) and human serum albumin (HSA) was investigated by UV-vis and fluorescence spectroscopy techniques. The results showed that BPA could bind to HSA molecule, which could cause the stretch of peptide chains. Also, the degraded BPA solution with a few residues could still interact with HSA. Otherwise, the influences of pH and ionic strength on the interaction were estimated. The fluorescence quenching modes of HSA initiated by BPA at three temperatures (298, 310 and 315 K) were all obtained using Stern-Volmer and Lineweaver-Burk equations. The number of binding sites (n), binding constants (K D ) and energy transfer efficiency (E) were all calculated. The thermodynamic parameters (ΔH, ΔG and ΔS) and binding distances (r) were all measured at the three temperatures, respectively. Synchronous fluorescence spectroscopy was also carried out. - Highlights: →The interaction between bisphenol A (BPA) and human serum albumin (HSA) was investigated. → The interaction between degraded BPA solution and HSA was also studied. → The fluorescence quenching mode of HSA initiated by BPA was obtained. → The number of binding site (n) and binding constant (K D ) and their binding distances (r) between BPA and HSA were calculated.

Interaction of biocompatible natural rosin-based surfactants with human serum albumin: A biophysical study

International Nuclear Information System (INIS)

Ishtikhar, Mohd; Ali, Mohd Sajid; Atta, Ayman M.; Al-Lohedan, H.A.; Nigam, Lokesh; Subbarao, Naidu; Hasan Khan, Rizwan

2015-01-01

Biophysical insight into interaction of biocompatible rosin-based surfactants with human serum albumin (HSA) was studied at physiological conditions using various spectroscopic, calorimetric and molecular docking approaches. The binding constant (K b ), enthalpy (ΔH 0 ), entropy (ΔS 0 ) and Gibbs free energy change (ΔG 0 ) were calculated by spectroscopic and calorimetric method. We have also calculated the probability of energy transfer by FRET analysis. The circular dichroism study showed that the cationic surfactant QRMAE significantly altered the secondary structure of HSA as compared to the nonionic rosin surfactants. The thermodynamic study was performed by ITC to determine binding constant as well as change in enthalpy of HSA in presence of rosin surfactants. It clearly showed that hydrogen binding and hydrophobic interaction play an important role in the binding of HSA to rosin surfactants. We have also performed molecular docking studies to locate the binding site on HSA and to visualize the mode of interaction. The present study provides a significant insight into HSA–rosin surfactants interaction, which also improves our understanding of the possible effect of rosin surfactants on human health. - Highlights: • RMPEG 750 has the highest Kb, Kq and Ksv value as compared to other rosin surfactants. • The probability of energy transfer from HSA to rosin surfactants was maximum in the case of RMPEG 750. • Cationic surfactant QRMAE significantly altered the secondary structure of the HSA as compared to other rosin surfactants. • Molecular docking and ITC experiment studies, to locate the binding site on HSA and to investigate the mode of interaction

Interaction study on bovine serum albumin physically binding to silver nanoparticles: Evolution from discrete conjugates to protein coronas

Energy Technology Data Exchange (ETDEWEB)

Guo, Jun; Zhong, Ruibo; Li, Wanrong; Liu, Yushuang; Bai, Zhijun; Yin, Jun; Liu, Jingran; Gong, Pei [Agricultural Nanocenter, School of Life Science, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot 010018 (China); Zhao, Xinmin, E-mail: zhao.xinmin@hotmail.com [School of Foreign Language, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot 010018 (China); Zhang, Feng, E-mail: fengzhang1978@hotmail.com [Agricultural Nanocenter, School of Life Science, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot 010018 (China)

2015-12-30

Graphical abstract: With the non-uniform coating of amphiphilic polymer, the silver nanoparticles (AgNPs) can form protein coronas which can become discrete protein–nanoparticle conjugates when controlling the protein–nanoparticle molar ratios. The protein's conformational changes upon binding NPs was also studied by both circular dichroism and three-dimensional fluorescence spectroscopy. - Highlights: • The amphiphilic polymer coating can not only transfer hydrophobic NPs into water soluble, but also providing a thick shell responsible for the strong physisorption to proteins without significantly changing their spatial conformations. • NP with discrete proteins can be simply obtained by a simple mixing procedure followed by a gel electrophoresis separation, and the resulting conjugates are robust enough to resist common separation techniques like gel electrophoresis. • In combination with the universal amphiphilic polymer coating strategy and the physisorption mediated protein–NP conjugation, proteins like BSA can be effectively conjugated to different materials such as noble metal, semiconductor and magnetic NPs. • In contrast to chemical coupling methods, the physisorption mediated protein–NP conjugation holds facile, robust and reversible advantages, which may find wide applications in nano-biomedicine field. - Abstract: The nanostructures formed by inorganic nanoparticles together with organic molecules especially biomolecules have attracted increasing attention from both industries and researching fields due to their unique hybrid properties. In this paper, we systemically studied the interactions between amphiphilic polymer coated silver nanoparticles and bovine serum albumins by employing the fluorescence quenching approach in combination with the Stern-Volmer and Hill equations. The binding affinity was determined to 1.30 × 10{sup 7} M{sup −1} and the interaction was spontaneously driven by mainly the van der Waals force and

Interaction study on bovine serum albumin physically binding to silver nanoparticles: Evolution from discrete conjugates to protein coronas

Science.gov (United States)

Guo, Jun; Zhong, Ruibo; Li, Wanrong; Liu, Yushuang; Bai, Zhijun; Yin, Jun; Liu, Jingran; Gong, Pei; Zhao, Xinmin; Zhang, Feng

2015-12-01

The nanostructures formed by inorganic nanoparticles together with organic molecules especially biomolecules have attracted increasing attention from both industries and researching fields due to their unique hybrid properties. In this paper, we systemically studied the interactions between amphiphilic polymer coated silver nanoparticles and bovine serum albumins by employing the fluorescence quenching approach in combination with the Stern-Volmer and Hill equations. The binding affinity was determined to 1.30 × 107 M-1 and the interaction was spontaneously driven by mainly the van der Waals force and hydrogen-bond mediated interactions, and negatively cooperative from the point of view of thermodynamics. With the non-uniform coating of amphiphilic polymer, the silver nanoparticles can form protein coronas which can become discrete protein-nanoparticle conjugates when controlling their molar ratios of mixing. The protein's conformational changes upon binding nanoparticles was also studied by using the three-dimensional fluorescence spectroscopy.

Cellular Specificity of the Blood-CSF Barrier for Albumin Transfer across the Choroid Plexus Epithelium

DEFF Research Database (Denmark)

Liddelow, Shane A; Dzięgielewska, Katarzyna M; Møllgård, Kjeld

2014-01-01

in albumin transport into developing brain, however the exact mechanism remains unknown. We postulate that SPARC is a docking site for albumin, mediating its uptake and transfer by choroid plexus epithelial cells from blood into cerebrospinal fluid (CSF). We used in vivo physiological measurements...... of transfer of endogenous (mouse) and exogenous (human) albumins, in situ Proximity Ligation Assay (in situ PLA), and qRT-PCR experiments to examine the cellular mechanism mediating protein transfer across the blood-CSF interface. We report that at all developmental stages mouse albumin and SPARC gave...... positive signals with in situ PLAs in plasma, CSF and within individual plexus cells suggesting a possible molecular interaction. In contrast, in situ PLA experiments in brain sections from mice injected with human albumin showed positive signals for human albumin in the vascular compartment that were only...

Intermolecular interaction of fosinopril with bovine serum albumin (BSA): The multi-spectroscopic and computational investigation.

Science.gov (United States)

Zhou, Kai-Li; Pan, Dong-Qi; Lou, Yan-Yue; Shi, Jie-Hua

2018-04-16

The intermolecular interaction of fosinopril, an angiotensin converting enzyme inhibitor with bovine serum albumin (BSA), has been investigated in physiological buffer (pH 7.4) by multi-spectroscopic methods and molecular docking technique. The results obtained from fluorescence and UV absorption spectroscopy revealed that the fluorescence quenching mechanism of BSA induced by fosinopril was mediated by the combined dynamic and static quenching, and the static quenching was dominant in this system. The binding constant, K b , value was found to lie between 2.69 × 10 3 and 9.55 × 10 3  M -1 at experimental temperatures (293, 298, 303, and 308 K), implying the low or intermediate binding affinity between fosinopril and BSA. Competitive binding experiments with site markers (phenylbutazone and diazepam) suggested that fosinopril preferentially bound to the site I in sub-domain IIA on BSA, as evidenced by molecular docking analysis. The negative sign for enthalpy change (ΔH 0 ) and entropy change (ΔS 0 ) indicated that van der Waals force and hydrogen bonds played important roles in the fosinopril-BSA interaction, and 8-anilino-1-naphthalenesulfonate binding assay experiments offered evidence of the involvements of hydrophobic interactions. Moreover, spectroscopic results (synchronous fluorescence, 3-dimensional fluorescence, and Fourier transform infrared spectroscopy) indicated a slight conformational change in BSA upon fosinopril interaction. Copyright © 2018 John Wiley & Sons, Ltd.

Radioimmunoassay for urinary albumin

International Nuclear Information System (INIS)

Woo, J.; Floyd, M.; Cannon, D.C.; Kahan, B.

1978-01-01

We describe a rapid, sensitive, and precise radioimmunoassay for urinary albumin (U/sub alb/). Aliquots of diluted urine were incubated at room temperature for 1 h with 125 I-labelled albumin and a rabbit antiserum monospecifid for human albumin. Phase separation was effected by the double-antibody technique. The dose-response curve was linear in the range of 15.6 to 10,000 ng, equivalent to 4 to 3000 mg/liter of urine. The limit of sensitivity was 16 ng of albumin. The coefficient of assay variation was 4.8%, both at 44 mg/liter and at 1304 mg/liter. A displacement curve obtained with a serially diluted urine sample of high albumin concentration was completely superimposable with the curve for which human albumin was used as a standard. In 26 normal individuals the range for U/sub alb/ was 2.2 to 12.6 mg/24 h, and for albumin clearance (C/sub alb/), 1.8 x 10 -5 --19.6 x 10 -5 ml/min. After renal homografts in 25 patients, U/sub alb/ ranged from 16.9 to 9928 mg/24 h, and C/sub alb/ from 2.7 x 10 -4 to 1.7 x 10 -1 ml/min. Both increased U/sub alb/ and C/sub alb/ correlated well with the severity of renal homograft rejection

Interaction mechanisms between organic UV filters and bovine serum albumin as determined by comprehensive spectroscopy exploration and molecular docking.

Science.gov (United States)

Ao, Junjie; Gao, Li; Yuan, Tao; Jiang, Gaofeng

2015-01-01

Organic UV filters are a group of emerging PPCP (pharmaceuticals and personal care products) contaminants. Current information is insufficient to understand the in vivo processes and health risks of organic UV filters in humans. The interaction mechanism of UV filters with serum albumin provides critical information for the health risk assessment of these active ingredients in sunscreen products. This study investigates the interaction mechanisms of five commonly used UV filters (2-hydroxy-4-methoxybenzophenone, BP-3; 2-ethylhexyl 4-methoxycinnamate, EHMC; 4-methylbenzylidene camphor, 4-MBC; methoxydibenzoylmethane, BDM; homosalate, HMS) with bovine serum albumin (BSA) by spectroscopic measurements of fluorescence, circular dichroism (CD), competitive binding experiments and molecular docking. Our results indicated that the fluorescence of BSA was quenched by these UV filters through a static quenching mechanism. The values of the binding constant (Ka) ranged from (0.78±0.02)×10(3) to (1.29±0.01)×10(5) L mol(-1). Further exploration by synchronous fluorescence and CD showed that the conformation of BSA was demonstrably changed in the presence of these organic UV filters. It was confirmed that the UV filters can disrupt the α-helical stability of BSA. Moreover, the results of molecular docking revealed that the UV filter molecule is located in site II (sub-domain IIIA) of BSA, which was further confirmed by the results of competitive binding experiments. In addition, binding occurred mainly through hydrogen bonding and hydrophobic interaction. This study raises critical concerns regarding the transportation, distribution and toxicity effects of organic UV filters in human body. Copyright © 2014 Elsevier Ltd. All rights reserved.

Exploring the interaction between Salvia miltiorrhiza and human serum albumin: Insights from herb-drug interaction reports, computational analysis and experimental studies

Science.gov (United States)

Shao, Xin; Ai, Ni; Xu, Donghang; Fan, Xiaohui

2016-05-01

Human serum albumin (HSA) binding is one of important pharmacokinetic properties of drug, which is closely related to in vivo distribution and may ultimately influence its clinical efficacy. Compared to conventional drug, limited information on this transportation process is available for medicinal herbs, which significantly hampers our understanding on their pharmacological effects, particularly when herbs and drug are co-administrated as polytherapy to the ailment. Several lines of evidence suggest the existence of Salvia miltiorrhiza-Warfarin interaction. Since Warfarin is highly HSA bound in the plasma with selectivity to site I, it is critical to evaluate the possibility of HSA-related herb-drug interaction. Herein an integrated approach was employed to analyze the binding of chemicals identified in S. miltiorrhiza to HSA. Molecular docking simulations revealed filtering criteria for HSA site I compounds that include docking score and key molecular determinants for binding. For eight representative ingredients from the herb, their affinity and specificity to HSA site I was measured and confirmed fluorometrically, which helps to improve the knowledge of interaction mechanisms between this herb and HSA. Our results indicated that several compounds in S. miltiorrhiza were capable of decreasing the binding constant of Warfarin to HSA site I significantly, which may increase free drug concentration in vivo, contributing to the herb-drug interaction observed clinically. Furthermore, the significance of HSA mediated herb-drug interactions was further implied by manual mining on the published literatures on S. miltiorrhiza.

Determination of association constants between steroid compounds and albumins by partial-filling ACE.

Science.gov (United States)

Amundsen, Lotta K; Sirén, Heli

2007-10-01

ACE is a popular technique for evaluating association constants between drugs and proteins. However, ACE has not previously been applied to study the association between electrically neutral biomolecules and plasma proteins. We studied the affinity between human and bovine serum albumins (HSA and BSA, respectively) and three neutral endogenous steroid hormones (testosterone, epitestosterone and androstenedione) and two synthetic analogues (methyltestosterone and fluoxymesterone) by applying the partial-filling technique in ACE (PF-ACE). From the endocrinological point of view, the distribution of endogenous steroids among plasma components is of great interest. Strong interactions with albumins suppress the biological activity of steroids. Notable differences in the association constants were observed. In the case of the endogenous steroids, the interactions between testosterone and the albumins were strongest, and those between androstenedione and the albumins were substantially weaker. The association constants, K(b), for testosterone, epitestosterone and androstenedione and HSA at 37 degrees C were 32 100 +/- 3600, 21 600 +/- 1500 and 13 300 +/- 1300 M(-1), respectively, while the corresponding values for the steroids and BSA were 18 800 +/- 1500, 14 000 +/- 400 and 7800 +/- 900 M(-1). Methyltestosterone was bound even more strongly than testosterone, while fluoxymesterone was only weakly bound by the albumins. Finally, the steroids were separated by PF-ACE with HSA and BSA used as resolving components.

Interactions between imazethapyr and bovine serum albumin: Spectrofluorimetric study

Energy Technology Data Exchange (ETDEWEB)

Pacheco, Maria E. [Division Quimica Analitica, Departamento de Quimica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Buenos Aires (Argentina); Bruzzone, Liliana, E-mail: bruzzone@quimica.unlp.edu.ar [Division Quimica Analitica, Departamento de Quimica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Buenos Aires (Argentina)

2012-10-15

The interaction between imazethapyr (IMA) and bovine serum albumin (BSA) was investigated by fluorescence spectroscopy. The Stern-Volmer quenching constant (K{sub SV}) at three temperatures was evaluated in order to determine the quenching mechanism. The dependence of fluorescence quenching on viscosity was also evaluated for this purpose. The results showed that IMA quenches the fluorescence intensity of BSA through a static quenching process. The values of the binding constant for the formed BSA-IMA complex and the number of binding sites were found to be 1.51 Multiplication-Sign 10{sup 5} M{sup -1} and 0.77, respectively, at room temperature. Based on the calculated thermodynamic parameters, the forces that dominate the binding process are hydrogen bonds and van der Waals forces, and the binding process is spontaneous and exothermic. The quenching of protein fluorescence by iodide ion was used to probe the accessibility of tryptophan residues in BSA and the change in accessibility induced by the presence of IMA. According to the obtained results, the BSA-IMA complex is formed in the site where the Trp-134 is located, causing it to become less exposed to the solvent. - Highlights: Black-Right-Pointing-Pointer Fluorescence spectroscopy helps to understand protein binding mechanisms. Black-Right-Pointing-Pointer Quenching measurements reveal the nature of the binding process involved. Black-Right-Pointing-Pointer Iodine ion can be used to study the change in accessibility of tryptophan residues. Black-Right-Pointing-Pointer Thermodynamic parameters for the binding reaction confirm binding modes.

A DSC study of zinc binding to bovine serum albumin (BSA

Directory of Open Access Journals (Sweden)

SANJA OSTOJIC

2007-04-01

Full Text Available The thermal denaturation of bovine serum albumin (BSA is a kinetically and thermodynamically controlled process. The effects of zinc binding to bovine serum albumin (BSA, followed by differential scanning calorimetry (DSC, were investigated in this work, with the purpose of obtaining a better understanding of the albumin/zinc interaction. From the DSC curves, the thermodynamic parameters of protein denaturation were obtained, i.e., the temperature of thermal transition maximum (Tm, calorimetric enthalpy (DHcal, van't Hoff enthalpy (DHvH, the number of binding sites (I, II, the binding constants for each binding site (KbI, KbII and the average number of ligands bound per mole of native protein XN. The thermodynamic data of protein unfolding showed that zinc binding to bovine serum albumin increases the stability of the protein (higher values of DHcal and the different ratio DHcal/DHvH indicates the perturbation of the protein during thermal denaturation.

Interaction of biocompatible natural rosin-based surfactants with human serum albumin: A biophysical study

Energy Technology Data Exchange (ETDEWEB)

Ishtikhar, Mohd [Protein Biophysics Laboratory, Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002 (India); Ali, Mohd Sajid [Surfactant Research Chair, Department of Chemistry, King Saud University, P.O. Box-2455, Riyadh 11451 (Saudi Arabia); Atta, Ayman M. [Surfactant Research Chair, Department of Chemistry, King Saud University, P.O. Box-2455, Riyadh 11451 (Saudi Arabia); Petroleum Application department, Egyptian Petroleum Research Institute, Ahmad Elzomor St., Nasr city, Cairo-11727 (Egypt); Al-Lohedan, H.A. [Surfactant Research Chair, Department of Chemistry, King Saud University, P.O. Box-2455, Riyadh 11451 (Saudi Arabia); Nigam, Lokesh; Subbarao, Naidu [Centre for Computational Biology and Bioinformatics, School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067 (India); Hasan Khan, Rizwan, E-mail: rizwanhkhan@hotmail.com [Protein Biophysics Laboratory, Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002 (India)

2015-11-15

Biophysical insight into interaction of biocompatible rosin-based surfactants with human serum albumin (HSA) was studied at physiological conditions using various spectroscopic, calorimetric and molecular docking approaches. The binding constant (K{sub b}), enthalpy (ΔH{sup 0}), entropy (ΔS{sup 0}) and Gibbs free energy change (ΔG{sup 0}) were calculated by spectroscopic and calorimetric method. We have also calculated the probability of energy transfer by FRET analysis. The circular dichroism study showed that the cationic surfactant QRMAE significantly altered the secondary structure of HSA as compared to the nonionic rosin surfactants. The thermodynamic study was performed by ITC to determine binding constant as well as change in enthalpy of HSA in presence of rosin surfactants. It clearly showed that hydrogen binding and hydrophobic interaction play an important role in the binding of HSA to rosin surfactants. We have also performed molecular docking studies to locate the binding site on HSA and to visualize the mode of interaction. The present study provides a significant insight into HSA–rosin surfactants interaction, which also improves our understanding of the possible effect of rosin surfactants on human health. - Highlights: • RMPEG 750 has the highest Kb, Kq and Ksv value as compared to other rosin surfactants. • The probability of energy transfer from HSA to rosin surfactants was maximum in the case of RMPEG 750. • Cationic surfactant QRMAE significantly altered the secondary structure of the HSA as compared to other rosin surfactants. • Molecular docking and ITC experiment studies, to locate the binding site on HSA and to investigate the mode of interaction.

Size-dependent interaction of silica nanoparticles with lysozyme and bovine serum albumin proteins

Science.gov (United States)

Yadav, Indresh; Aswal, Vinod K.; Kohlbrecher, Joachim

2016-05-01

The interaction of three different sized (diameter 10, 18, and 28 nm) anionic silica nanoparticles with two model proteins—cationic lysozyme [molecular weight (MW) 14.7 kDa)] and anionic bovine serum albumin (BSA) (MW 66.4 kDa) has been studied by UV-vis spectroscopy, dynamic light scattering (DLS), and small-angle neutron scattering (SANS). The adsorption behavior of proteins on the nanoparticles, measured by UV-vis spectroscopy, is found to be very different for lysozyme and BSA. Lysozyme adsorbs strongly on the nanoparticles and shows exponential behavior as a function of lysozyme concentration irrespective of the nanoparticle size. The total amount of adsorbed lysozyme, as governed by the surface-to-volume ratio, increases on lowering the size of the nanoparticles for a fixed volume fraction of the nanoparticles. On the other hand, BSA does not show any adsorption for all the different sizes of the nanoparticles. Despite having different interactions, both proteins induce similar phase behavior where the nanoparticle-protein system transforms from one phase (clear) to two phase (turbid) as a function of protein concentration. The phase behavior is modified towards the lower concentrations for both proteins with increasing the nanoparticle size. DLS suggests that the phase behavior arises as a result of the nanoparticles' aggregation on the addition of proteins. The size-dependent modifications in the interaction potential, responsible for the phase behavior, have been determined by SANS data as modeled using the two-Yukawa potential accounting for the repulsive and attractive interactions in the systems. The protein-induced interaction between the nanoparticles is found to be short-range attraction for lysozyme and long-range attraction for BSA. The magnitude of attractive interaction irrespective of protein type is enhanced with increase in the size of the nanoparticles. The total (attractive+repulsive) potential leading to two-phase formation is found to be

Improved anticancer effects of albumin-bound paclitaxel nanoparticle via augmentation of EPR effect and albumin-protein interactions using S-nitrosated human serum albumin dimer.

Science.gov (United States)

Kinoshita, Ryo; Ishima, Yu; Chuang, Victor T G; Nakamura, Hideaki; Fang, Jun; Watanabe, Hiroshi; Shimizu, Taro; Okuhira, Keiichiro; Ishida, Tatsuhiro; Maeda, Hiroshi; Otagiri, Masaki; Maruyama, Toru

2017-09-01

In the latest trend of anticancer chemotherapy research, there were many macromolecular anticancer drugs developed based on enhanced permeability and retention (EPR) effect, such as albumin bound paclitaxel nanoparticle (nab- PTX, also called Abraxane ® ). However, cancers with low vascular permeability posed a challenge for these EPR based therapeutic systems. Augmenting the intrinsic EPR effect with an intrinsic vascular modulator such as nitric oxide (NO) could be a promising strategy. S-nitrosated human serum albumin dimer (SNO-HSA Dimer) shown promising activity previously was evaluated for the synergistic effect when used as a pretreatment agent in nab-PTX therapy against various tumor models. In the high vascular permeability C26 murine colon cancer subcutaneous inoculation model, SNO-HSA Dimer enhanced tumor selectivity of nab-PTX, and attenuated myelosuppression. SNO-HSA Dimer also augmented the tumor growth inhibition of nab-PTX in low vascular permeability B16 murine melanoma subcutaneous inoculation model. Furthermore, nab-PTX therapy combined with SNO-HSA Dimer showed higher antitumor activity and improved survival rate of SUIT2 human pancreatic cancer orthotopic model. In conclusion, SNO-HSA Dimer could enhance the therapeutic effect of nab-PTX even in low vascular permeability or intractable pancreatic cancers. The possible underlying mechanisms of action of SNO-HSA Dimer were discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Application of photoactivation in the preparation of radiopharmaceuticals. Pt. 3. Human serum albumin labelled with technetium (99mTc)

International Nuclear Information System (INIS)

Komarek, P.; Kleisner, I.; Konopkova, M.; Komarkova, I.

1997-01-01

Human serum albumin was photoactivated with UV light at 254 nm and labelled with technetium ( 99m Tc) by reducing pertechnetate ( 99m Tc) with stannous chloride. Radiochemical purity was determined by using paper chromatography, columns and electrophoresis. The biodistribution of labelled albumin in rats was assessed by activity counting in isolated organs 15 and 60 minutes after administration. Photoactivation increases the number of free SH groups, which affect favourably the labelling efficiency. Irradiated albumin exhibits a higher labelling efficiency (99%) than non-irradiated albumin (96%). The structural changes depend on the UV radiation dose, concentration of irradiated substances, and metal ion content (Sn 2+ ). The results obtained suggest that the elimination from blood of albumin whose structure has been altered by photoactivation can be accelerated, thereby creating favourable conditions for its application in the diagnosis of inflammatory diseases. (author)

Study of binding interaction between anthelmintic 2, 3-dihydroquinazolin-4-ones with bovine serum albumin by spectroscopic methods

Energy Technology Data Exchange (ETDEWEB)

Hemalatha, K.; Madhumitha, G., E-mail: madhumitha.g@vit.ac.in

2016-10-15

A new series of brominated derivatives of 2, 3-dihydroquinazolin-4(1H)-one were synthesized and their structures were confirmed using IR, NMR and mass spectra. The synthesized derivatives were screened for their in vitro anthelmintic activity. The investigations on interaction of the bioactive compound, 2i with bovine serum albumin (BSA) were evaluated. The quenching mechanism of the compound, 2i was deduced based on the results of Stern–Volmer equation. The number of binding site, prediction of binding site region and the changes in the secondary structure of protein were predicted using various spectroscopic studies.

Urinary albumin in space missions

DEFF Research Database (Denmark)

Cirillo, Massimo; De Santo, Natale G; Heer, Martina

2002-01-01

Proteinuria was hypothesized for space mission but research data are missing. Urinary albumin, as index of proteinuria, was analyzed in frozen urine samples collected by astronauts during space missions onboard MIR station and on ground (control). Urinary albumin was measured by a double antibody...... radioimmunoassay. On average, 24h urinary albumin was 27.4% lower in space than on ground; the difference was statistically significant. Low urinary albumin excretion could be another effect of exposure to weightlessness (microgravity)....

Interaction of hydrogen and oxygen with bulk defects and surfaces of metals

International Nuclear Information System (INIS)

Besenbacher, F.

1994-05-01

The thesis deals with the interaction of hydrogen with defects in metals and the interaction of hydrogen and oxygen with metal surfaces studied by ion-beam techniques and scanning tunneling microscopy (STM), respectively. The first part of the thesis discusses the interaction of hydrogen with simple defects in transition metals. The trap-binding enthalpies and the lattice location of hydrogen trapped to vacancies have been determined, and an extremely simple and versatile picture of the hydrogen-metal interaction has evolved, in which the trap strength is mainly determined by the local electron density. Any dilution of the lattice will lead to a trap, vacancies and voids being the strongest trap. It is found that hydrogen trapped to vacancies in fcc metals is quantum-mechanically delocalized, and the excitation energies for the hydrogen in the vacancy potential are a few MeV only. The interaction of hydrogen with metal surfaces is studied by the transmission channeling (TC) technique. It is found that hydrogen chemisorbs in the highest-coordinated sites on the surfaces, and that there is a direct relationship between the hydrogen-metal bond length and the coordination number for the hydrogen. In the final part of the thesis the dynamics of the chemisorption process for oxygen and hydrogen on metal surfaces is studied by STM, a fascinating and powerful technique for exploring the atomic-scale realm of surfaces. It is found that there is a strong coupling between the chemisorption process and the distortion of the metal surface. The adsorbates induce a surface reconstruction, i.e. metal-metal bond breaks and metal-adsorbate bounds form. Whereas hydrogen interacts weakly with the metals and induces reconstructions where only nnn metals bonds are broken, oxygen interacts strongly with the metal, and the driving force for the O-induced reconstructions appears to be the formation of low-coordinated metal-O rows, formed by breaking of nn metal bonds. Finally it is shown

Emission solvatochromic behavior of a pentacoordinated Zn(II) complex: A viable tool for studying the metallodrug–protein interaction

Energy Technology Data Exchange (ETDEWEB)

Ricciardi, Loredana, E-mail: loredana.ricciardi@unical.it [Department of Chemistry and Chemical Technology, University of Calabria, I-87036 Rende (CS) (Italy); Centre of Excellence “Functional Nanostructured Materials” CEMIF.CAL, LASCAMM and CR INSTM, INSTM Calabria Unit, and CNR-IPCF-UOS Cosenza - Licryl Laboratory, I-87036 Rende (CS) (Italy); Pucci, Daniela; Pirillo, Sante; La Deda, Massimo [Department of Chemistry and Chemical Technology, University of Calabria, I-87036 Rende (CS) (Italy); Centre of Excellence “Functional Nanostructured Materials” CEMIF.CAL, LASCAMM and CR INSTM, INSTM Calabria Unit, and CNR-IPCF-UOS Cosenza - Licryl Laboratory, I-87036 Rende (CS) (Italy)

2014-07-01

A metal complex with antitumoral activity, Zn(Curcumin)(bypiridine)Cl, was characterized from a photophysical point of view, showing a green emission and a positive solvatochromism. These characteristics can be conveniently used to study its interaction with Human Serum Albumin (HSA), a protein carrier of many non-aqueous biologically-active compounds in the blood stream. The intrinsic fluorescence of HSA was quenched by Fluorescence Resonance Energy Transfer toward the Zn(II) complex, and the Stern–Volmer equation was applied to determine the bimolecular quenching rate constant of the interaction. - Highlights: • Albumin binding information is a key characteristic of drug pharmacology. • Fluorescence spectroscopy offers a simple method for revealing drug–protein interaction. • The fluorescence of the Zn(II) complex and its solvatochromisms has allowed studying the binding from a dual perspective.

SPECTROSCOPIC STUDY OF INTERACTION OF SODIUM DOLUTEGRAVIR WITH HUMAN SERUM ALBUMIN

Directory of Open Access Journals (Sweden)

A. V. Yegorova

2017-11-01

Full Text Available Drug-protein binding has become an important research field in life sciences, chemistry and clinical medicine. Under physiological conditions, in vitro interaction between the antiviral drug 2 Sodium (4R, 12aS-9-{[(2,4-difluorophenylmethyl]carbamoyl}-4-methyl-6,8-dioxo3,4,6,8, 12,12a-hexahydro-2H-pyrido[1’,2’:4,5]pyrazino[2, 1-b][1,3]oxazin-7 –olate (dolutegravir sodium, DN and human serum albumin (HSA was investigated at excitation wavelength 280 nm and at different temperatures (298 K and 313 K by fluorescence emission spectroscopy. The emission of HSA was characterized by a broad emission band at 346 nm. The results of the experiment showed that DN quench the intrinsic fluorescence of the protein as a result of static interaction in the HSA -DN system, which is confirmed by shifts in the difference UV spectra of the HSA -DN and the reduction of the binding constant for the HSA -DN system with increasing temperature. The constant (KA =9,82· 103 L·mol-1 at 298 K and the number of binding sites of the HSA –DN system are established. The negative values of enthalpy change (ΔHº and entropy change (ΔSº can be attributed in part to van der Waals forces and in part to the formation of hydrogen bonds. A value of 2,14 nm for the average distance r between DN (acceptor and tryptophan residues of HSA (donor was derived from the fluorescence resonance energy transfer. The overlap of the absorbance spectrum of DN with the fluorescence emission spectrum of HAS has been shown. Since, the pharmaceutical firms need standardized screens for protein binding in the first step of new drug design, this kind of study of interaction between HSA with DN would be useful in pharmaceutical industry and clinical medicine.

Binding of streptomycin with bovine serum albumin: Energetics and conformational aspects

International Nuclear Information System (INIS)

Jha, Niki S.; Kishore, Nand

2009-01-01

Thermodynamics of the binding of antibiotic streptomycin to bovine serum albumin have been studied using isothermal titration calorimetry in combination with fluorescence, UV-vis and circular dichroism spectroscopies. The values of van't Hoff enthalpy calculated from the temperature dependence of the binding constant do not agree with the calorimetric enthalpies indicating temperature dependent conformational changes in the protein upon binding. With increase in the ionic strength, reduction in the binding affinity of streptomycin to BSA is observed suggesting the predominance of electrostatic interactions in the binding. The contribution of hydrophobic interactions in the binding is also demonstrated by decrease in binding affinity in the presence of tetrabutylammonium bromide (TBAB). The value of binding affinity in the presence of sucrose indicates that hydrogen bonding is not a significant contribution in complexation. The results have permitted quantitative evaluation of the interaction of streptomycin with bovine serum albumin

Renal albumin excretion: twin studies identify influences of heredity, environment, and adrenergic pathway polymorphism

DEFF Research Database (Denmark)

Rao, Fangwen; Wessel, Jennifer; Wen, Gen

2007-01-01

biosynthesis (tyrosine hydroxylase), catabolism (monoamine oxidase A), storage/release (chromogranin A), receptor target (dopamine D1 receptor), and postreceptor signal transduction (sorting nexin 13 and rho kinase). Epistasis (gene-by-gene interaction) occurred between alleles at rho kinase, tyrosine...... hydroxylase, chromogranin A, and sorting nexin 13. Dopamine D1 receptor polymorphism showed pleiotropic effects on both albumin and dopamine excretion. These studies establish new roles for heredity and environment in albumin excretion. Urinary excretions of albumin and catecholamines are highly heritable......, and their parallel suggests adrenergic mediation of early glomerular permeability alterations. Albumin excretion is influenced by multiple adrenergic pathway genes and is, thus, polygenic. Such functional links between adrenergic activity and glomerular injury suggest novel approaches to its prediction, prevention...

Effect of Temperature on Tolbutamide Binding to Glycated Serum Albumin

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Agnieszka Szkudlarek

2017-03-01

Full Text Available Glycation process occurs in protein and becomes more pronounced in diabetes when an increased amount of reducing sugar is present in bloodstream. Glycation of protein may cause conformational changes resulting in the alterations of its binding properties even though they occur at a distance from the binding sites. The changes in protein properties could be related to several pathological consequences such as diabetic and nondiabetic cardiovascular diseases, cataract, renal dysfunction and Alzheimer’s disease. The experiment was designed to test the impact of glycation process on sulfonylurea drug tolbutamide-albumin binding under physiological (T = 309 K and inflammatory (T = 311 K and T = 313 K states using fluorescence and UV-VIS spectroscopies. It was found in fluorescence analysis experiments that the modification of serum albumin in tryptophanyl and tyrosyl residues environment may affect the tolbutamide (TB binding to albumin in subdomain IIA and/or IIIA (Sudlow’s site I and/or II, and also in subdomains IB and IIB. We estimated the binding of tolbutamide to albumin described by a mixed nature of interaction (specific and nonspecific. The association constants Ka (L∙mol−1 for tolbutamide at its high affinity sites on non-glycated albumin were in the range of 1.98–7.88 × 104 L∙mol−1 (λex = 275 nm, 1.20–1.64 × 104 L∙mol−1 (λex = 295 nm and decreased to 1.24–0.42 × 104 L∙mol−1 at λex = 275 nm (T = 309 K and T = 311 K and increased to 2.79 × 104 L∙mol−1 at λex = 275 nm (T = 313 K and to 4.43–6.61 × 104 L∙mol−1 at λex = 295 nm due to the glycation process. Temperature dependence suggests the important role of van der Waals forces and hydrogen bonding in hydrophobic interactions between tolbutamide and both glycated and non-glycated albumin. We concluded that the changes in the environment of TB binding of albumin in subdomain IIA and/or IIIA as well as in subdomains IB and IIB influence on

Albumin and pre-albumin levels do not reflect the nutritional status of female adolescents with restrictive eating disorders.

Science.gov (United States)

Huysentruyt, Koen; De Schepper, Jean; Vanbesien, Jesse; Vandenplas, Yvan

2016-04-01

Albumin and pre-albumin are frequently used as nutritional markers in clinical practice. We examined whether serum albumin and pre-albumin were predicted by body mass index (BMI), hydration and/or inflammation in female adolescents with a recently diagnosed restrictive eating disorder (RED). This was a retrospective study of female adolescents with RED from 2002 to 2011. Low albumin and pre-albumin levels were defined as nutritional status in adolescents with RED. ©2015 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

Study on interaction of Ligupurpuroside A with bovine serum albumin by multi-spectroscopic methods

Energy Technology Data Exchange (ETDEWEB)

Shen, Liang-liang [College of Life Sciences, Shenzhen Key Laboratory of Marine Bioresources and Ecology/Shenzhen Key Laboratory of Microbial Genetic Engineering, Shenzhen 518060 (China); Xu, Hong, E-mail: xuhong@szu.edu.cn [College of Life Sciences, Shenzhen Key Laboratory of Marine Bioresources and Ecology/Shenzhen Key Laboratory of Microbial Genetic Engineering, Shenzhen 518060 (China); Huang, Feng-wen; Li, Yi; Xiao, Jie; Xiao, Hua-feng; Ying, Ming; Tian, Sheng-li; Yang, Zhen; Liu, Gang; Hu, Zhang-li [College of Life Sciences, Shenzhen Key Laboratory of Marine Bioresources and Ecology/Shenzhen Key Laboratory of Microbial Genetic Engineering, Shenzhen 518060 (China); He, Zhen-dan, E-mail: hezhendan@126.com [School of Medicine, Shenzhen University, Shenzhen 518060 (China); Zhou, Kai [Shenzhen Marine Environment and Resource Monitoring Center, Shenzhen 518060 (China)

2014-10-15

The interaction of Ligupurpuroside A with bovine serum albumin (BSA) has been investigated by fluorescence spectra, UV–vis absorption spectra, three-dimensional (3D) fluorescence spectra, synchronous fluorescence spectra and circular dichroism (CD) spectra along with a molecular docking method. The fluorescence experiments indicate that Ligupurpuroside A can quench the intrinsic fluorescence of BSA through a combined quenching way at the low concentration of Ligupurpuroside A, and a static quenching procedure at the high concentration. The thermodynamic analysis suggests that hydrogen bonds and van der Waals forces are the main forces between BSA and Ligupurpuroside A. According to the theory of Förster's non-radiation energy transfer, the binding distance between BSA and Ligupurpuroside A was calculated to be 2.73 nm, which implies that energy transfer occurs between BSA and Ligupurpuroside A. All these experimental results have been validated by the protein–ligand docking studies which show that Ligupurpuroside A binds to the residues located in the hydrophobic cavity on subdomain IIA of BSA. In addition, conformation change of BSA was observed from three-dimensional fluorescence spectra, synchronous fluorescence spectra and circular dichroism spectra under experimental conditions. - Highlights: • The interaction of Ligupurpuroside A with BSA was investigated. • The fluorescence quenching of BSA induced by Ligupurpuroside A is a combined quenching process. • The main interaction forces were hydrogen bonds and van der Waals forces. • Ligupurpuroside A binding results in a decrease in α-helix.

Synthesis of biological active thiosemicarbazone and characterization of the interaction with human serum albumin

International Nuclear Information System (INIS)

Yu, Wangshu; Shi, Lei; Hui, Guangquan; Cui, Fengling

2013-01-01

The synthesis of a new biological active reagent, 2-((1,4-dihydroxy)-9,10-anthraquinone) aldehyde thiosemicarbazone (DHAQTS), was designed. The interaction between DHAQTS and HSA was studied by fluorescence spectroscopy in combination with molecular modeling under simulation of physiological conditions. According to the results of fluorescence measurements, the quenching mechanism was suggested to be static. The thermodynamic parameters are calculated by van't Hoff equation, which demonstrated that hydrophobic interactions are the predominant intermolecular forces stabilizing the complex. The number of binding sites (n) was calculated. Through the site marker competitive experiment, DHAQTS was confirmed to be located in site I of HSA. The binding distance r=2.83 nm between the donor HSA and acceptor DHAQTS was obtained according to Förster's non-radiative energy transfer theory. The three-dimensional fluorescence spectral results showed the conformation and microenvironment of HSA changed in the presence of DHAQTS. The effects of common ions on the binding of DHAQTS to HSA were also evaluated. The experimental results were in agreement with the results obtained via a molecular docking study. - Highlights: ► 2-((1,4-dihydroxy)-9,10-anthraquinone)aldehyde thiosemicarbazone (DHAQTS) was synthesized. ► DHAQTS can quench the fluorescence of human serum albumin (HSA) by static quenching mechanism. ► Hydrophobic interactions were the predominant intermolecular forces. ► The competitive experiment was carried out to identify the DHAQTS binding site on HSA. ► Three-dimensional spectra confirmed DHAQTS caused the conformational change of HSA.

The impact of change in albumin assay on reference intervals, prevalence of 'hypoalbuminaemia' and albumin prescriptions.

Science.gov (United States)

Coley-Grant, Deon; Herbert, Mike; Cornes, Michael P; Barlow, Ian M; Ford, Clare; Gama, Rousseau

2016-01-01

We studied the impact on reference intervals, classification of patients with hypoalbuminaemia and albumin infusion prescriptions on changing from a bromocresol green (BCG) to a bromocresol purple (BCP) serum albumin assay. Passing-Bablok regression analysis and Bland-Altman plot were used to compare Abbott BCP and Roche BCG methods. Linear regression analysis was used to compare in-house and an external laboratory Abbott BCP serum albumin results. Reference intervals for Abbott BCP serum albumin were derived in two different laboratories using pathology data from adult patients in primary care. Prescriptions for 20% albumin infusions were compared one year before and one year after changing the albumin method. Abbott BCP assay had a negative bias of approximately 6 g/L compared with Roche BCG method.There was good agreement (y = 1.04 x - 1.03; R(2 )= 0.9933) between in-house and external laboratory Abbott BCP results. Reference intervals for the serum albumin Abbott BCP assay were 31-45 g/L, different to those recommended by Pathology Harmony and the manufacturers (35-50 g/L). Following the change in method there was a large increase in the number of patients classified as hypoalbuminaemic using Pathology Harmony references intervals (32%) but not when retrospectively compared to locally derived reference intervals (16%) compared with the previous year (12%). The method change was associated with a 44.6% increase in albumin prescriptions. This equated to an annual increase in expenditure of £35,234. We suggest that serum albumin reference intervals be method specific to prevent misclassification of albumin status in patients. Change in albumin methodology may have significant impact on hospital resources. © The Author(s) 2015.

Spectroscopic Studies on the Interaction of Acid Yellow With Bovine Serum Albumin

International Nuclear Information System (INIS)

Pan Xingren; Liu Rutao; Qin Pengfei; Wang Li; Zhao Xingchen

2010-01-01

Azo dyes, which are common in the environment, can be toxic to various organisms. In order to determine the molecular mechanism of acid yellow 11(AY) toxicity, we studied the effect of AY exposure to the common protein bovine serum albumin (BSA) by several spectroscopic techniques including fluorescence spectroscopy, ultraviolet spectrophotometry (UV) and circular dichroism (CD). It could be concluded from the fluorescence spectra that the quenching effect of BSA by AY was mainly due to complex formation which was unrelated to the absorption of AY. The enthalpy change (ΔH) and entropy change (ΔS) were found to be -21.94 kJ/mol and 30.04 Jmol -1 K -1 , respectively. The results confirm that electrostatic attraction was the predominant intermolecular force between BSA and AY. Furthermore, the binding distance (r) between AY and the inner tryptophan residue of BSA was determined to be 3.541 nm on the basis of Forster theory of non-radiative energy transfer. In addition, the conformational changes of BSA in the presence of AY were also analyzed by UV and CD. These results indicated that AY could interact with BSA by complex formation, which also affected the structure of BSA.

Quadrupole interaction in zinc metal

International Nuclear Information System (INIS)

Vetterling, W.T.; Pound, R.V.

1977-01-01

To allow measurement of the quadrupole interaction in zinc metal, the enriched ZnO was reduced to zinc metal powder and compressed into a pill of thickness 1.4 gm/cm 2 . Sources were made by diffusing 20 mCi of 67 Ga into sintered copper pills. The transducer was based on a cylinder of PZT-4 with 1 / 2 -inch length and could cover linearly a velocity range of +-100 μ/s at 200 Hz. The multiscalar was a modified Northern model NS600, with a minimum dwell time of 20 μs, and with a 10-count buffer at the input to eliminate deadtime from memory cycling

Curcumin-incorporated albumin nanoparticles and its tumor image

International Nuclear Information System (INIS)

Gong, Guangming; Wu, Rongchun; Pan, Qinqin; Wang, Kaikai; Sun, Yong; Lu, Ying

2015-01-01

Albumin is an ideal carrier for hydrophobic drugs. This paper reports a facile route to develop human serum albumin (HSA)–curcumin (CCM) nanoparticles, in which β-mercaptoethanol (β-ME) acted as an inducer and CCM acted as a bridge. Fluorescence quenching and conformational changes in HSA–CCM nanoparticles occurred during assembly. Disulfide bonds and hydrophobic interactions may play a key role in assembly. HSA–CCM nanoparticles were about 130 nm in size, and the solubility of CCM increased by more than 500 times. The HSA–CCM nanoparticles could accumulate at the cytoplasm of tumor cells and target the tumor tissues. Therefore, HSA nanoparticles fabricated by β-ME denaturation are promising nanocarriers for hydrophobic substances from chemotherapy drugs to imaging probes. (paper)

Curcumin-incorporated albumin nanoparticles and its tumor image

Science.gov (United States)

Gong, Guangming; Pan, Qinqin; Wang, Kaikai; Wu, Rongchun; Sun, Yong; Lu, Ying

2015-01-01

Albumin is an ideal carrier for hydrophobic drugs. This paper reports a facile route to develop human serum albumin (HSA)-curcumin (CCM) nanoparticles, in which β-mercaptoethanol (β-ME) acted as an inducer and CCM acted as a bridge. Fluorescence quenching and conformational changes in HSA-CCM nanoparticles occurred during assembly. Disulfide bonds and hydrophobic interactions may play a key role in assembly. HSA-CCM nanoparticles were about 130 nm in size, and the solubility of CCM increased by more than 500 times. The HSA-CCM nanoparticles could accumulate at the cytoplasm of tumor cells and target the tumor tissues. Therefore, HSA nanoparticles fabricated by β-ME denaturation are promising nanocarriers for hydrophobic substances from chemotherapy drugs to imaging probes.

Curcumin-incorporated albumin nanoparticles and its tumor image.

Science.gov (United States)

Gong, Guangming; Pan, Qinqin; Wang, Kaikai; Wu, Rongchun; Sun, Yong; Lu, Ying

2015-01-30

Albumin is an ideal carrier for hydrophobic drugs. This paper reports a facile route to develop human serum albumin (HSA)-curcumin (CCM) nanoparticles, in which β-mercaptoethanol (β-ME) acted as an inducer and CCM acted as a bridge. Fluorescence quenching and conformational changes in HSA-CCM nanoparticles occurred during assembly. Disulfide bonds and hydrophobic interactions may play a key role in assembly. HSA-CCM nanoparticles were about 130 nm in size, and the solubility of CCM increased by more than 500 times. The HSA-CCM nanoparticles could accumulate at the cytoplasm of tumor cells and target the tumor tissues. Therefore, HSA nanoparticles fabricated by β-ME denaturation are promising nanocarriers for hydrophobic substances from chemotherapy drugs to imaging probes.

The investigation of the interaction between piracetam and bovine serum albumin by spectroscopic methods

Science.gov (United States)

Guo, Xingjia; Han, Xiaowei; Tong, Jian; Guo, Chuang; Yang, Wenfeng; Zhu, Jifen; Fu, Bing

2010-03-01

The interaction between piracetam (OPA) with bovine serum albumin (BSA) has been thoroughly studied by fluorescence quenching technique in combination with UV-vis absorption, Fourier transform infrared (FT-IR), and circular dichroism (CD) spectroscopies under the simulative physiological conditions. The quenching of BSA fluorescence by OPA was found to be a static quenching process. The binding constants ( K a) are 3.014, 2.926, and 2.503 × 10 3 M -1 at 292, 298, and 309 K, respectively. According to the van't Hoff equation, the thermodynamic functions standard enthalpy (Δ H) and standard entropy (Δ S) for the reaction were calculated to be -74.560 kJ mol -1 and -159.380 J mol -1 K -1, which indicated that OPA binds to BSA mainly by hydrogen bonds and van der Waals interactions. The binding distance between BSA and OPA was calculated to be 4.10 nm according to the theory of FÖrster's non-radiation energy transfer. The displacement experiments confirmed that OPA could bind to the site I of BSA. Furthermore, the effects of pH and some common ions on the binding constant were also examined. And the alterations of protein secondary structure in the presence of OPA were observed by the CD and FT-IR spectra.

Biomolecular Interaction Study of Cyclolinopeptide A with Human Serum Albumin

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Ben Rempel

2010-01-01

Full Text Available The kinetics, energetics, and structure of Cyclolinopeptide A binding with Human Serum Albumin were investigated with surface plasmon resonance and circular dichroism. The complex is formed through slow recognition kinetics that is temperature sensitive in the range of 20°C–37°C. The overall reaction was observed to be endothermic (ΔH=204 kJ mol−1 and entropy driven (ΔS=746 J mol−1K−1 with overall small changes to the tertiary structure.

Interactive influences of bioactive trace metals on biological production in oceanic waters

International Nuclear Information System (INIS)

Bruland, K.W.; Donat, J.R.; Hutchins, D.A.

1991-01-01

The authors present an overview of the oceanic chemistries of the bioactive trace metals, Mn, Fe, Co, Ni, Cu, and Zn; the authors combine field data with results from laboratory phytoplankton culture-trace metal studies and speculate on the potential influences of these trace metals on oceanic plankton production and species composition. Most field studies have focused on the effects of single metals. However, they propose that synergistic and antagonistic interactions between multiple trace metals could be very important in the oceans. Trace metal antagonisms that may prove particularly important are those between Cu and the potential biolimiting metals Fe, Mn, and Zn. These antagonistic interactions could have the greatest influence on biological productivity in areas of the open ocean isolated from terrestrial inputs, such as the remote high nutrient regions of the Pacific and Antarctic Oceans. The emerging picture of trace metal-biota interactions in these oceanic areas is one in which biology strongly influences distribution and chemical speciation of all these bioactive trace metals. It also seems likely that many of these bioactive trace metals and their speciation may influence levels of primary productivity, species composition, and trophic structure. Future investigations should give more complete consideration to the interactive effects of biologically important trace metals

21 CFR 862.1035 - Albumin test system.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Albumin test system. 862.1035 Section 862.1035....1035 Albumin test system. (a) Identification. An albumin test system is a device intended to measure the albumin concentration in serum and plasma. Albumin measurements are used in the diagnosis and...

Influence of galloyl moiety in interaction of epicatechin with bovine serum albumin: a spectroscopic and thermodynamic characterization.

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Sandip Pal

Full Text Available The health benefits stemming from green tea are well known, but the exact mechanism of its biological activity is not elucidated. Epicatechin (EC and epicatechin gallate (ECG are two dietary catechins ubiquitously present in green tea. Serum albumins functionally carry these catechins through the circulatory system and eliminate reactive oxygen species (ROS induced injury. In the present study ECG is observed to have higher antioxidant activity; which is attributed to the presence of galloyl moiety. The binding affinity of these catechins to bovine serum albumin (BSA will govern the efficacy of their biological activity. EC and ECG bind with BSA with binding constants 1.0 × 10(6 M(-1 and 6.6 × 10(7 M(-1, respectively. Changes in secondary structure of BSA on interaction with EC and ECG have been identified by circular dichroism (CD and Fourier transform infrared (FT-IR spectroscopy. Thermodynamic characterization reveals the binding process to be exothermic, spontaneous and entropy driven. Mixed binding forces (hydrophobic, electrostatic and hydrogen bonding exist between ECG and BSA. Binding site for EC is primarily site-II in sub-domain IIIA of BSA and for ECG; it is site-I in sub-domain IIA. ECG with its high antioxidant activity accompanied by high affinity for BSA could be a model in drug designing.

Interactions of nanobubbles with bovine serum albumin and papain films on gold surfaces.

Science.gov (United States)

Kolivoska, Viliam; Gál, Miroslav; Hromadová, Magdaléna; Lachmanová, Stepánka; Pospísil, Lubomír

2011-12-01

Nanobubbles formed on monocrystalline gold/water interface by means of the ethanol-to-water solvent exchange were exposed to the solutions of either bovine serum albumin or papain proteins. Both proteins do not change the position of nanobubbles in water, as observed by in situ tapping mode atomic force microscopy imaging before and after the introduction of the protein. The aqueous environment was subsequently replaced by ethanol. While all nanobubbles were found to dissolve in ethanol in the presence of bovine serum albumin, most of them survived when papain was employed. The protective ability of papain was ascribed to its resistance towards the protein denaturation in aqueous solutions of ethanol. The authors employed in situ atomic force nanolithography to investigate the nanomorphology of the papain/nanobubble assemblies in ethanol.

Interaction and sonodynamic damage activity of acridine red (AD-R) to bovine serum albumin (BSA)

Energy Technology Data Exchange (ETDEWEB)

Chen, Dandan; Xie, Jinhui; Wu, Qiong; Fan, Ping; Wang, Jun, E-mail: wangjun888tg@126.com

2015-04-15

The sonodynamic therapy (SDT) has become an attractive antitumor treatment method in recent years, but the selection of sonosensitizer, mechanism of damage biomolecule and kind of reactive oxygen species (ROS) generated during sonodynamic process have not been investigated in detail. In this paper, the acridine red (AD-R), as a sonosensitizer, combining with ultrasonic irradiation to damage bovine serum albumin (BSA) was investigated. At first, the interaction of AD-R to BSA molecules in aqueous solution was studied by fluorescence spectroscopy. As judged from the experimental results, the quenching mechanism of BSA fluorescence belongs to a static process. Synchronous fluorescence spectra demonstrate that the binding and damage sites to BSA molecules are mainly on the tryptophan residues. The generation and kind of generated ROS were also estimated by the method of oxidation and extraction photometry. This paper may offer some valuable references for the study of the sonodynamic activity and application of AD-R in SDT for tumor treatment. - Highlights: ●Acridine red (AD-R) is used to study interaction with BSA. ●Spectroscopy is used to study sonodynamic damage activity of AD-R to BSA. ●Generation of ROS caused by AD-R under ultrasonic irradiation was determined.

Interaction and sonodynamic damage activity of acridine red (AD-R) to bovine serum albumin (BSA)

International Nuclear Information System (INIS)

Chen, Dandan; Xie, Jinhui; Wu, Qiong; Fan, Ping; Wang, Jun

2015-01-01

The sonodynamic therapy (SDT) has become an attractive antitumor treatment method in recent years, but the selection of sonosensitizer, mechanism of damage biomolecule and kind of reactive oxygen species (ROS) generated during sonodynamic process have not been investigated in detail. In this paper, the acridine red (AD-R), as a sonosensitizer, combining with ultrasonic irradiation to damage bovine serum albumin (BSA) was investigated. At first, the interaction of AD-R to BSA molecules in aqueous solution was studied by fluorescence spectroscopy. As judged from the experimental results, the quenching mechanism of BSA fluorescence belongs to a static process. Synchronous fluorescence spectra demonstrate that the binding and damage sites to BSA molecules are mainly on the tryptophan residues. The generation and kind of generated ROS were also estimated by the method of oxidation and extraction photometry. This paper may offer some valuable references for the study of the sonodynamic activity and application of AD-R in SDT for tumor treatment. - Highlights: ●Acridine red (AD-R) is used to study interaction with BSA. ●Spectroscopy is used to study sonodynamic damage activity of AD-R to BSA. ●Generation of ROS caused by AD-R under ultrasonic irradiation was determined

Interaction of terbium group metal oxides with carbon

International Nuclear Information System (INIS)

Vodop'yanov, A.G.; Baranov, S.V.; Kozhevnikov, G.N.

1990-01-01

Mechanism of carbothermal reduction of terbium group metals from oxides is investigated using thermodynamic and kinetic analyses. Interaction of metal oxides with carbon covers dissociation of metal oxides and reduction by carbon monoxide, which contribution into general reduction depends on CO pressure. Temperatures of reaction beginning for batch initial components at P=1.3x10 -4 and P CO =0.1 MPa and of formation of oxycarbide melts are determined

Surface and micellar properties of Chloroquine Diphosphate and its interactions with surfactants and Human Serum Albumin

International Nuclear Information System (INIS)

Usman, Muhammad; Siddiq, Mohammad

2013-01-01

Highlights: ► Free energy of adsorption is more negative than free energy of micellization. ► Shifts in UV/Visible spectra in presence of SDS indicated interaction of CLQ with SDS. ► The decrease in fluorescence intensity of HSA by CLQ shows its binding with HSA. -- Abstract: This manuscript addresses the physicochemical behavior of an antimalarial drug Chloroquine Diphosphate (CLQ) as well as its interaction with anionic surfactants and Human Serum Albumin (HSA). Surface tension and specific conductivity were employed to detect the critical micelle concentration (CMC) and thus its surface and thermodynamic parameters were calculated. Solubilization of this drug within micelles of anionic surfactant sodium dodecyl sulfate (SDS) has also been studied. UV/Visible spectroscopy was used to calculate partition coefficient (K x ), free energy of partition and number of drug molecules per micelle. The complexation of drug with HSA at physiological conditions (pH 7.4) has also been analyzed by using UV/Visible and fluorescence spectroscopy. The values of drug-protein binding constant, number of binding sites and free energy of binding were calculated

Presence of albumin mRNA precursors in nuclei of analbuminemic rat liver lacking cytoplasmic albumin mRNA.

OpenAIRE

Esumi, H; Takahashi, Y; Sekiya, T; Sato, S; Nagase, S; Sugimura, T

1982-01-01

Analbuminemic rats, which lack serum albumin, were previously found to have no albumin mRNA in the cytoplasm of the liver. In the present study, the existence of nuclear albumin mRNA precursors in the liver of analbuminemic rats was examined by RNA X cDNA hybridization kinetics. Albumin mRNA precursors were present in the nuclei of analbuminemic rat liver at almost normal levels, despite the absence of albumin mRNA from the cytoplasm. Nuclear RNA of analbuminemic rat liver was subjected to el...

Recombinant human serum albumin hydrogel as a novel drug delivery vehicle

International Nuclear Information System (INIS)

Hirose, Masaaki; Tachibana, Akira; Tanabe, Toshizumi

2010-01-01

Serum albumin acts as a physiological carrier for various compounds including drugs. A hydrogel consisting of recombinant human serum albumin (rHSA) was prepared to take advantage of drug binding ability of albumin for a sustained drug release carrier. The hydrogel was prepared by mixing rHSA and dithiothreitol and casted to a polystyrene mold. Hydrogel formation was thought to occur through the intermolecular interaction of the hydrophobic groups by protein denaturation. The release of sodium benzoate and salicylic acid from the hydrogel completed in 2 h, while warfarin release continued for 24 h. The total amounts of the drugs released from 100 mg of 15 and 5% rHSA hydrogel were 2.3 and 1.4 μmol for warfarin, 1.4 and 1.1 μmol for salicylic acid and 0.9 and 0.9 μmol for sodium benzoate. These results reflected the order of the binding ability of drugs for intact albumin indicating that the drug binding ability of HSA still remained after the hydrogel formation. However, fibroblast cells attached and proliferated well on the hydrogel, indicating that denaturation of rHSA proceeded to the extent to allow the cell attachment. The present rHSA hydrogel might be suitable for a sustained release carrier of drugs having affinity for albumin.

Recombinant human serum albumin hydrogel as a novel drug delivery vehicle

Energy Technology Data Exchange (ETDEWEB)

Hirose, Masaaki, E-mail: Hirose.Masaaki@mh.mt-pharma.co.jp [Advanced Medical Research Laboratory, Research Division, Mitsubishi Tanabe Pharma Corporation, 3-16-89 Kashima, Yodogawa-ku, Osaka 532-8505 (Japan); Department of Applied Chemistry and Bioengineering, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); Tachibana, Akira; Tanabe, Toshizumi [Department of Applied Chemistry and Bioengineering, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan)

2010-06-15

Serum albumin acts as a physiological carrier for various compounds including drugs. A hydrogel consisting of recombinant human serum albumin (rHSA) was prepared to take advantage of drug binding ability of albumin for a sustained drug release carrier. The hydrogel was prepared by mixing rHSA and dithiothreitol and casted to a polystyrene mold. Hydrogel formation was thought to occur through the intermolecular interaction of the hydrophobic groups by protein denaturation. The release of sodium benzoate and salicylic acid from the hydrogel completed in 2 h, while warfarin release continued for 24 h. The total amounts of the drugs released from 100 mg of 15 and 5% rHSA hydrogel were 2.3 and 1.4 {mu}mol for warfarin, 1.4 and 1.1 {mu}mol for salicylic acid and 0.9 and 0.9 {mu}mol for sodium benzoate. These results reflected the order of the binding ability of drugs for intact albumin indicating that the drug binding ability of HSA still remained after the hydrogel formation. However, fibroblast cells attached and proliferated well on the hydrogel, indicating that denaturation of rHSA proceeded to the extent to allow the cell attachment. The present rHSA hydrogel might be suitable for a sustained release carrier of drugs having affinity for albumin.

Asperity interaction in adhesive contact of metallic rough surfaces

International Nuclear Information System (INIS)

Sahoo, Prasanta; Banerjee, Atanu

2005-01-01

The analysis of adhesive contact of metallic rough surfaces considering the effect of asperity interaction is the subject of this investigation. The micro-contact model of asperity interactions developed by Zhao and Chang (2001 Trans. ASME: J. Tribol. 123 857-64) is combined with the elastic plastic adhesive contact model developed by Chang et al (1988 Trans. ASME: J. Tribol. 110 50-6) to consider the asperity interaction and elastic-plastic deformation in the presence of surface forces simultaneously. The well-established elastic adhesion index and plasticity index are used to consider the different contact conditions. Results show that asperity interaction influences the load-separation behaviour in elastic-plastic adhesive contact of metallic rough surfaces significantly and, in general, adhesion is reduced due to asperity interactions

Nanoparticles of Conjugated Methotrexate-Human Serum Albumin: Preparation and Cytotoxicity Evaluations

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Azade Taheri

2011-01-01

Full Text Available Methotrexate-human serum albumin conjugates were developed by a simple carbodiimide reaction. Methotrexate-human serum albumin conjugates were then crosslinked with 1-ethyl-3-(3-dimethylaminopropyl carbodiimide HCl (EDC to form nanoparticles. The size of nanoparticles determined by laser light scattering and TEM was between 90–150 nm. Nanoparticles were very stable at physiologic conditions (PBS pH 7.4, 37∘C and after incubation with serum. The effect of amount of EDC used for crosslinking on the particle size and free amino groups of nanoparticles was examined. The amount of crosslinker showed no significant effect on the size of nanoparticles but free amino groups of nanoparticles were decreased by increasing the crosslinker. The physicochemical interactions between methotrexate and human serum albumin were investigated by differential scanning calorimetry (DSC. Nanoparticles were more cytotoxic on T47D cells compared to free methotrexate. Moreover, methotrexate-human serum albumin nanoparticles decreased the IC50 value of methotrexate on T47D cells in comparison with free methotrexate.

Nanoparticles of Conjugated Methotrexate-Human Serum Albumin: Preparation and Cytotoxicity Evaluations

International Nuclear Information System (INIS)

Taheri, A.; Atyabi, F.; Nouri, F.S.; Ahadi, F.; Derakhshan, M.A.; Dinarvand, R.; Atyabi, F.; Ghahremani, M.H.; Ostad, S.N.; Dinarvand, R.; Amini, M.; Ghahremani, M.H.; Ostad, S.N.; Mansoori, P.

2011-01-01

Methotrexate-human serum albumin conjugates were developed by a simple carbodiimide reaction. Methotrexate-human serum albumin conjugates were then crosslinked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide HCl (EDC) to form nanoparticles. The size of nanoparticles determined by laser light scattering and TEM was between 90 150 nm. Nanoparticles were very stable at physiologic conditions (PBS pH 7.4, 37 degree C) and after incubation with serum. The effect of amount of EDC used for crosslinking on the particle size and free amino groups of nanoparticles was examined. The amount of cross linker showed no significant effect on the size of nanoparticles but free amino groups of nanoparticles were decreased by increasing the cross linker. The physicochemical interactions between methotrexate and human serum albumin were investigated by differential scanning calorimetry (DSC). Nanoparticles were more cytotoxic on T 47 D cells compared to free methotrexate. Moreover, methotrexate-human serum albumin nanoparticles decreased the C50 value of methotrexate on T 47 D cells in comparison with free methotrexate.

[Novel Hyphenated Techniques of Atomic Spectrometry for Metal Species Interaction with Biomolecules].

Science.gov (United States)

Li, Yan; Yan, Xiu-ping

2015-09-01

Trace metals may be adopted by biological systems to assist in the syntheses and metabolic functions of genes (DNA and RNA) and proteins in the environment. These metals may be beneficial or may pose a risk to humans and other life forms. Novel hybrid techniques are required for studies on the interaction between different metal species and biomolecules, which is significant for biology, biochemistry, nutrition, agriculture, medicine, pharmacy, and environmental science. In recent years, our group dwells on new hyphenated techniques based on capillary electrophoresis (CE), electrothermal atomic absorption spectrometry (ETAAS), and inductively coupled plasma mass spectroscopy (ICP-MS), and their application for different metal species interaction with biomolecules such as DNA, HSA, and GSH. The CE-ETAAS assay and CE-ICP-MS assay allow sensitively probing the level of biomolecules such as DNA damage by different metal species and extracting the kinetic and thermodynamic information on the interactions of different metal species with biomolecules, provides direct evidences for the formation of different metal species--biomolecule adducts. In addition, the consequent structural information were extracted from circular dichroism (CD) and X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and Fourier transform infrared (FTIR) spectroscopy. The present works represent the most complete and extensive study to date on the interactions between different metal species with biomolecules, and also provide new evidences for and insights into the interactions of different metal species with biomolecules for further understanding of the toxicological effects of metal species.

Long-range interactions between excited helium and alkali-metal atoms

KAUST Repository

Zhang, J.-Y.

2012-12-03

The dispersion coefficients for the long-range interaction of the first four excited states of He, i.e., He(2 1,3S) and He(2 1,3P), with the low-lying states of the alkali-metal atoms Li, Na, K, and Rb are calculated by summing over the reduced matrix elements of the multipole transition operators. For the interaction between He and Li the uncertainty of the calculations is 0.1–0.5%. For interactions with other alkali-metal atoms the uncertainty is 1–3% in the coefficient C5, 1–5% in the coefficient C6, and 1–10% in the coefficients C8 and C10. The dispersion coefficients Cn for the interaction of He(2 1,3S) and He(2 1,3P) with the ground-state alkali-metal atoms and for the interaction of He(2 1,3S) with the alkali-metal atoms in their first 2P states are presented in this Brief Report. The coefficients for other pairs of atomic states are listed in the Supplemental Material.

Human serum albumin mediated self-assembly of gold nanoparticles into hollow spheres

Energy Technology Data Exchange (ETDEWEB)

Nayak, Nimai C [Singapore-MIT Alliance, Manufacturing Systems and Technology Programme, Nanyang Technological University, 65 Nanyang Drive, 637460 (Singapore); Shin, Kwanwoo [Interdisciplinary Program of Integrated Biotechnology, Sogang University, Shinsoo-dong, Mapo-gu, Seoul 121-742 (Korea, Republic of)], E-mail: ncnayak@gmail.com

2008-07-02

The assembly of nanoparticles in topologically predefined superstructures is an important area in nanoscale architecture. In this paper, we report an unusual aggregation phenomenon involving L-lysine capped gold nanoparticles and human serum albumin into hollow nanospheres. The electrostatic interaction between positively charged L-lysine capped gold nanoparticles and negatively charged human serum albumin at physiological pH led to the assembly of the gold nanoparticles into hollow spheres. The phenomenon can be explained by the dry hole opening mechanism.

Human serum albumin mediated self-assembly of gold nanoparticles into hollow spheres

International Nuclear Information System (INIS)

Nayak, Nimai C; Shin, Kwanwoo

2008-01-01

The assembly of nanoparticles in topologically predefined superstructures is an important area in nanoscale architecture. In this paper, we report an unusual aggregation phenomenon involving L-lysine capped gold nanoparticles and human serum albumin into hollow nanospheres. The electrostatic interaction between positively charged L-lysine capped gold nanoparticles and negatively charged human serum albumin at physiological pH led to the assembly of the gold nanoparticles into hollow spheres. The phenomenon can be explained by the dry hole opening mechanism

Studies of the interaction of CS@ZnS:Mn with bovine serum albumin under illumination

Energy Technology Data Exchange (ETDEWEB)

Liu, Li, E-mail: 2476625723@qq.com [Institute of Agricultural Quality Standards and Testing Technology Research, Hubei Academy of Agricultural Science, Wuhan 430064 (China); Xiao, Ling [School of Resource and Environmental Science, Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan 430072 (China)

2015-09-15

Highlights: • The interaction and illumination damages of CS@ZnS:Mn D-dots to BSA were studied. • The quenching mechanism of CS@ZnS:Mn D-dots with BSA belongs to dynamic quenching. • The hydrophobic interaction plays a major role; the binding processes are spontaneous. • The FL enhancement of CS@ZnS:Mn D-dots by BSA under UV illumination was observed. • The probable mechanism is mainly a photo-induced free radical procedure. - Abstract: In this study, chitosan coated Mn-doped ZnS quantum dots (CS@ZnS:Mn D-dots) were obtained in aqueous media under ambient pressure. The interaction and illumination damages of CS@ZnS:Mn D-dots with bovine serum albumin (BSA) were studied by means of ultraviolet–visible (UV–vis) and fluorescence (FL) spectra. It was found that the FL of BSA was quenched by CS@ZnS:Mn D-dots. The dominating quenching mechanism of CS@ZnS:Mn D-dots with BSA belongs to dynamic quenching. Hydrophobic interaction plays a major role in the CS@ZnS:Mn–BSA interaction; binding processes are spontaneous. Influencing factors such as illumination time and CS@ZnS:Mn D-dots concentrations were considered. The FL quenching effect of BSA by CS@ZnS:Mn D-dots is enhanced with the increase of illumination time and CS@ZnS:Mn D-dots concentration. The FL enhancement of CS@ZnS:Mn D-dots by BSA under UV illumination was also observed. It was proved that, the interaction of CS@ZnS:Mn D-dots with BSA under UV illumination is mainly a result of a photo-induced free radical procedure. CS@ZnS:Mn D-dots may be used as photosensitizers in photodynamic therapy.

Studies of the interaction of CS@ZnS:Mn with bovine serum albumin under illumination

International Nuclear Information System (INIS)

Liu, Li; Xiao, Ling

2015-01-01

Highlights: • The interaction and illumination damages of CS@ZnS:Mn D-dots to BSA were studied. • The quenching mechanism of CS@ZnS:Mn D-dots with BSA belongs to dynamic quenching. • The hydrophobic interaction plays a major role; the binding processes are spontaneous. • The FL enhancement of CS@ZnS:Mn D-dots by BSA under UV illumination was observed. • The probable mechanism is mainly a photo-induced free radical procedure. - Abstract: In this study, chitosan coated Mn-doped ZnS quantum dots (CS@ZnS:Mn D-dots) were obtained in aqueous media under ambient pressure. The interaction and illumination damages of CS@ZnS:Mn D-dots with bovine serum albumin (BSA) were studied by means of ultraviolet–visible (UV–vis) and fluorescence (FL) spectra. It was found that the FL of BSA was quenched by CS@ZnS:Mn D-dots. The dominating quenching mechanism of CS@ZnS:Mn D-dots with BSA belongs to dynamic quenching. Hydrophobic interaction plays a major role in the CS@ZnS:Mn–BSA interaction; binding processes are spontaneous. Influencing factors such as illumination time and CS@ZnS:Mn D-dots concentrations were considered. The FL quenching effect of BSA by CS@ZnS:Mn D-dots is enhanced with the increase of illumination time and CS@ZnS:Mn D-dots concentration. The FL enhancement of CS@ZnS:Mn D-dots by BSA under UV illumination was also observed. It was proved that, the interaction of CS@ZnS:Mn D-dots with BSA under UV illumination is mainly a result of a photo-induced free radical procedure. CS@ZnS:Mn D-dots may be used as photosensitizers in photodynamic therapy

Application of a new method for data analysis of isothermal titration calorimetry in the interaction between human serum albumin and Ni{sup 2+}[Serum albumin; Nickel; Isothermal titration calorimetry; Calorimetric method

Energy Technology Data Exchange (ETDEWEB)

Saboury, Ali Akbar. E-mail: saboury@chamran.ut.ac.ir

2003-12-01

The interaction of human serum albumin (HAS) with divalent nickel ion was studied by isothermal titration calorimetry (ITC) in 30 mM Tris buffer, pH 7.0. There is a set of eight identical and independent binding sites for nickel ions on the protein at the temperature of 300 K. A new calorimetric data analysis allows the determination of the complete set of thermodynamic parameters. The binding isotherm for nickel-HSA interaction is easily obtained by carrying out two different ITC experiments. In the first experiment, the enthalpy of binding for one mole of nickel ion to one mole of binding site on HSA ({delta}H=-36.5 kJ) is obtained, and is used in a second experiment to determine the binding isotherm and to find the number of binding sites (g=8) and the equilibrium constant (K=0.57 {mu}M{sup -1})

Interactions of hydrogen isotopes and oxides with metal tubes

International Nuclear Information System (INIS)

Longhurst, G. R.; Cleaver, J.

2008-01-01

Understanding and accounting for interaction of hydrogen isotopes and their oxides with metal surfaces is important for persons working with tritium systems. Reported data from several investigators have shown that the processes of oxidation, adsorption, absorption, and permeation are all coupled and interactive. A computer model has been developed for predicting the interaction of hydrogen isotopes and their corresponding oxides in a flowing carrier gas stream with the walls of a metallic tube, particularly at low hydrogen concentrations. An experiment has been constructed to validate the predictive model. Predictions from modeling lead to unexpected experiment results. (authors)

Interactions of hydrogen isotopes and oxides with metal tubes

Energy Technology Data Exchange (ETDEWEB)

Longhurst, G. R. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3860 (United States); Cleaver, J. [Idaho State Univ., 921 South 8th Avenue, Pocatello, ID 83201 (United States)

2008-07-15

Understanding and accounting for interaction of hydrogen isotopes and their oxides with metal surfaces is important for persons working with tritium systems. Reported data from several investigators have shown that the processes of oxidation, adsorption, absorption, and permeation are all coupled and interactive. A computer model has been developed for predicting the interaction of hydrogen isotopes and their corresponding oxides in a flowing carrier gas stream with the walls of a metallic tube, particularly at low hydrogen concentrations. An experiment has been constructed to validate the predictive model. Predictions from modeling lead to unexpected experiment results. (authors)

Interactions of Hydrogen Isotopes and Oxides with Metal Tubes

International Nuclear Information System (INIS)

Longhurst, Glen R.

2008-01-01

Understanding and accounting for interaction of hydrogen isotopes and their oxides with metal surfaces is important for persons working with tritium systems. Reported data from several investigators have shown that the processes of oxidation, adsorption, absorption, and permeation are all coupled and interactive. A computer model has been developed for predicting the interaction of hydrogen isotopes and their corresponding oxides in a flowing carrier gas stream with the walls of a metallic tube, particularly at low hydrogen concentrations. An experiment has been constructed to validate the predictive model. Predictions from modeling lead to unexpected experiment results

Enhancing Docetaxel Delivery to Multidrug-Resistant Cancer Cells with Albumin-Coated Nanocrystals.

Science.gov (United States)

Gad, Sheryhan F; Park, Joonyoung; Park, Ji Eun; Fetih, Gihan N; Tous, Sozan S; Lee, Wooin; Yeo, Yoon

2018-01-29

Intravenous delivery of poorly water-soluble anticancer drugs such as docetaxel (DTX) is challenging due to the low bioavailability and the toxicity related to solubilizing excipients. Colloidal nanoparticles are used as alternative carriers, but low drug loading capacity and circulation instability limit their clinical translation. To address these challenges, DTX nanocrystals (NCs) were prepared using Pluronic F127 as an intermediate stabilizer and albumin as a functional surface modifier, which were previously found to be effective in producing small and stable NCs. We hypothesize that the albumin-coated DTX NCs (DTX-F-alb) will remain stable in serum-containing medium so as to effectively leverage the enhanced permeability and retention effect. In addition, the surface-bound albumin, in its native form, may contribute to cellular transport of NCs through interactions with albumin-binding proteins such as secreted protein acidic and rich in cysteine (SPARC). DTX-F-alb NCs showed sheet-like structure with an average length, width, and thickness of 284 ± 96, 173 ± 56, and 40 ± 8 nm and remained stable in 50% serum solution at a concentration greater than 10 μg/mL. Cytotoxicity and cellular uptake of DTX-F-alb and unformulated (free) DTX were compared on three cell lines with different levels of SPARC expression and DTX sensitivity. While the uptake of free DTX was highly dependent on DTX sensitivity, DTX-F-alb treatment resulted in relatively consistent cellular levels of DTX. Free DTX was more efficient in entering drug-sensitive B16F10 and SKOV-3 cells than DTX-F-alb, with consistent cytotoxic effects. In contrast, multidrug-resistant NCI/ADR-RES cells took up DTX-F-alb more than free DTX with time and responded better to the former. This difference was reduced by SPARC knockdown. The high SPARC expression level of NCI/ADR-RES cells, the known affinity of albumin for SPARC, and the opposing effect of SPARC knockdown support that DTX-F-alb have exploited the

Thermodynamic Study of the Interaction of Bovine Serum Albumin and Amino Acids with Cellulose Nanocrystals.

Science.gov (United States)

Lombardo, Salvatore; Eyley, Samuel; Schütz, Christina; van Gorp, Hans; Rosenfeldt, Sabine; Van den Mooter, Guy; Thielemans, Wim

2017-06-06

The interaction of bovine serum albumin (BSA) with sulfated, carboxylated, and pyridinium-grafted cellulose nanocrystals (CNCs) was studied as a function of the degree of substitution by determining the adsorption isotherm and by directly measuring the thermodynamics of interaction. The adsorption of BSA onto positively charged pyridinium-grafted cellulose nanocrystals followed Langmuirian adsorption with the maximum amount of adsorbed protein increasing linearly with increasing degree of substitution. The binding mechanism between the positively charged pyridinum-grafted cellulose nanocrystals and BSA was found to be endothermic and based on charge neutralization. A positive entropy of adsorption associated with an increase of the degree of disorder upon addition of BSA compensated for the unfavorable endothermic enthalpy and enabled formation of pyridinium-g-CNC-BSA complexes. The endothermic enthalpy of adsorption was further found to decrease as a function of increasing degree of substitution. Negatively charged cellulose nanocrystals bearing sulfate and/or carboxylic functionalities were found to not interact significantly with the BSA protein. To investigate in more detail the role of single amino acids in the adsorption of proteins onto cellulose nanocrystals, we also studied the interaction of different types of amino acids with CNCs, i.e., charged (lysine, aspartic acid), aromatic (tryptophan, tyrosine), and polar (serine) amino acids. We found that none of the single amino acids bound with CNCs irrespective of surface charge and that therefore the binding of proteins with CNCs appears to require larger amino acid sequences that induce a greater entropic contribution to stabilize binding. Single amino acids are thus not adsorbed onto cellulose nanocrystals.

Cellular specificity of the blood-CSF barrier for albumin transfer across the choroid plexus epithelium.

Directory of Open Access Journals (Sweden)

Shane A Liddelow

Full Text Available To maintain the precise internal milieu of the mammalian central nervous system, well-controlled transfer of molecules from periphery into brain is required. Recently the soluble and cell-surface albumin-binding glycoprotein SPARC (secreted protein acidic and rich in cysteine has been implicated in albumin transport into developing brain, however the exact mechanism remains unknown. We postulate that SPARC is a docking site for albumin, mediating its uptake and transfer by choroid plexus epithelial cells from blood into cerebrospinal fluid (CSF. We used in vivo physiological measurements of transfer of endogenous (mouse and exogenous (human albumins, in situ Proximity Ligation Assay (in situ PLA, and qRT-PCR experiments to examine the cellular mechanism mediating protein transfer across the blood-CSF interface. We report that at all developmental stages mouse albumin and SPARC gave positive signals with in situ PLAs in plasma, CSF and within individual plexus cells suggesting a possible molecular interaction. In contrast, in situ PLA experiments in brain sections from mice injected with human albumin showed positive signals for human albumin in the vascular compartment that were only rarely identifiable within choroid plexus cells and only at older ages. Concentrations of both endogenous mouse albumin and exogenous (intraperitoneally injected human albumin were estimated in plasma and CSF and expressed as CSF/plasma concentration ratios. Human albumin was not transferred through the mouse blood-CSF barrier to the same extent as endogenous mouse albumin, confirming results from in situ PLA. During postnatal development Sparc gene expression was higher in early postnatal ages than in the adult and changed in response to altered levels of albumin in blood plasma in a differential and developmentally regulated manner. Here we propose a possible cellular route and mechanism by which albumin is transferred from blood into CSF across a sub

Serum albumin: accuracy and clinical use.

Science.gov (United States)

Infusino, Ilenia; Panteghini, Mauro

2013-04-18

Albumin is the major plasma protein and its determination is used for the prognostic assessment of several diseases. Clinical guidelines call for monitoring of serum albumin with specific target cut-offs that are independent of the assay used. This requires accurate and equivalent results among different commercially available methods (i.e., result standardization) through a consistent definition and application of a reference measurement system. This should be associated with the definition of measurement uncertainty goals based on medical relevance of serum albumin to make results reliable for patient management. In this paper, we show that, in the current situation, if one applies analytical goals for serum albumin measurement derived from its biologic variation, the uncertainty budget derived from each step of the albumin traceability chain is probably too high to fulfil established quality levels for albumin measurement and to guarantee the accuracy needed for clinical usefulness of the test. The situation is further worsened if non-specific colorimetric methods are used for albumin measurement as they represent an additional random source of uncertainty. Copyright © 2013 Elsevier B.V. All rights reserved.

Albumin for End-Stage Liver Disease

Science.gov (United States)

2012-01-01

Albumin has been widely used in patients with cirrhosis in an attempt to improve circulatory and renal functions. The benefits of albumin infusions in preventing the deterioration in renal function associated with large-volume paracentesis, spontaneous bacterial peritonitis, and established hepatorenal syndrome in conjunction with a vasoconstrictor are well established. While some of these indications are supported by the results of randomized studies, others are based only on clinical experience and have not been proved in prospective studies. The paucity of well-designed trials, the high cost of albumin, the lack of a clear-cut survival benefit, and fear of transmitting unknown infections make the use of albumin controversial. The recent development of the molecular adsorbent recirculating system, an albumin dialysis, is an example of the capacity of albumin to act by mechanisms other than its oncotic effect. Efforts should be made to define the indications for albumin use, the dose required, and predictors of response, so that patients gain the maximum benefit from its administration. PMID:22403494

Detecting microalbuminuria by urinary albumin/creatinine concentration ratio

DEFF Research Database (Denmark)

Jensen, J S; Clausen, P; Borch-Johnsen, K

1997-01-01

BACKGROUND: Microalbuminuria, i.e. a subclinical increase of the albumin excretion rate in urine, may be a novel atherosclerotic risk factor. This study aimed to test whether microalbuminuria can be identified by measurement of urinary albumin concentration or urinary albumin/creatinine concentra......BACKGROUND: Microalbuminuria, i.e. a subclinical increase of the albumin excretion rate in urine, may be a novel atherosclerotic risk factor. This study aimed to test whether microalbuminuria can be identified by measurement of urinary albumin concentration or urinary albumin/creatinine...... not included. Urinary albumin (Ualb) and creatinine (Ucreat) concentrations were measured in an overnight collected sample by enzyme-linked immunosorbent and colorimetric assays, respectively. Urinary albumin excretion rate (UAER) and urinary albumin/creatinine concentration ratio (Ualb/Ucreat) were calculated......, and 73%, 97%, and 73% for Ualb/Ucreat, respectively. CONCLUSIONS: It is concluded that measurement of the albumin/creatinine concentration ratio is a specific and quite sensitive alternative to measurement of the urinary albumin excretion rate in timed collections, when screening for microalbuminuria....

Synthesis of biological active thiosemicarbazone and characterization of the interaction with human serum albumin

Energy Technology Data Exchange (ETDEWEB)

Yu, Wangshu; Shi, Lei; Hui, Guangquan [College of Chemistry and Environmental Science, Henan Normal University, Xinxiang 453007 (China); Cui, Fengling, E-mail: fenglingcui@hotmail.com [College of Chemistry and Environmental Science, Henan Normal University, Xinxiang 453007 (China)

2013-02-15

The synthesis of a new biological active reagent, 2-((1,4-dihydroxy)-9,10-anthraquinone) aldehyde thiosemicarbazone (DHAQTS), was designed. The interaction between DHAQTS and HSA was studied by fluorescence spectroscopy in combination with molecular modeling under simulation of physiological conditions. According to the results of fluorescence measurements, the quenching mechanism was suggested to be static. The thermodynamic parameters are calculated by van't Hoff equation, which demonstrated that hydrophobic interactions are the predominant intermolecular forces stabilizing the complex. The number of binding sites (n) was calculated. Through the site marker competitive experiment, DHAQTS was confirmed to be located in site I of HSA. The binding distance r=2.83 nm between the donor HSA and acceptor DHAQTS was obtained according to Foerster's non-radiative energy transfer theory. The three-dimensional fluorescence spectral results showed the conformation and microenvironment of HSA changed in the presence of DHAQTS. The effects of common ions on the binding of DHAQTS to HSA were also evaluated. The experimental results were in agreement with the results obtained via a molecular docking study. - Highlights: Black-Right-Pointing-Pointer 2-((1,4-dihydroxy)-9,10-anthraquinone)aldehyde thiosemicarbazone (DHAQTS) was synthesized. Black-Right-Pointing-Pointer DHAQTS can quench the fluorescence of human serum albumin (HSA) by static quenching mechanism. Black-Right-Pointing-Pointer Hydrophobic interactions were the predominant intermolecular forces. Black-Right-Pointing-Pointer The competitive experiment was carried out to identify the DHAQTS binding site on HSA. Black-Right-Pointing-Pointer Three-dimensional spectra confirmed DHAQTS caused the conformational change of HSA.

Podocytes degrade endocytosed albumin primarily in lysosomes.

Science.gov (United States)

Carson, John M; Okamura, Kayo; Wakashin, Hidefumi; McFann, Kim; Dobrinskikh, Evgenia; Kopp, Jeffrey B; Blaine, Judith

2014-01-01

Albuminuria is a strong, independent predictor of chronic kidney disease progression. We hypothesize that podocyte processing of albumin via the lysosome may be an important determinant of podocyte injury and loss. A human urine derived podocyte-like epithelial cell (HUPEC) line was used for in vitro experiments. Albumin uptake was quantified by Western blot after loading HUPECs with fluorescein-labeled (FITC) albumin. Co-localization of albumin with lysosomes was determined by confocal microscopy. Albumin degradation was measured by quantifying FITC-albumin abundance in HUPEC lysates by Western blot. Degradation experiments were repeated using HUPECs treated with chloroquine, a lysosome inhibitor, or MG-132, a proteasome inhibitor. Lysosome activity was measured by fluorescence recovery after photo bleaching (FRAP). Cytokine production was measured by ELISA. Cell death was determined by trypan blue staining. In vivo, staining with lysosome-associated membrane protein-1 (LAMP-1) was performed on tissue from a Denys-Drash trangenic mouse model of nephrotic syndrome. HUPECs endocytosed albumin, which co-localized with lysosomes. Choloroquine, but not MG-132, inhibited albumin degradation, indicating that degradation occurs in lysosomes. Cathepsin B activity, measured by FRAP, significantly decreased in HUPECs exposed to albumin (12.5% of activity in controls) and chloroquine (12.8%), and declined further with exposure to albumin plus chloroquine (8.2%, plysosomes are involved in the processing of endocytosed albumin in podocytes, and lysosomal dysfunction may contribute to podocyte injury and glomerulosclerosis in albuminuric diseases. Modifiers of lysosomal activity may have therapeutic potential in slowing the progression of glomerulosclerosis by enhancing the ability of podocytes to process and degrade albumin.

Antioxidant flavonoids bind human serum albumin

Science.gov (United States)

Kanakis, C. D.; Tarantilis, P. A.; Polissiou, M. G.; Diamantoglou, S.; Tajmir-Riahi, H. A.

2006-10-01

Human serum albumin (HSA) is a principal extracellular protein with a high concentration in blood plasma and carrier for many drugs to different molecular targets. Flavonoids are powerful antioxidants and prevent DNA damage. The antioxidative protections are related to their binding modes to DNA duplex and complexation with free radicals in vivo. However, flavonoids are known to inhibit the activities of several enzymes such as calcium phospholipid-dependent protein kinase, tyrosine protein kinase from rat lung, phosphorylase kinase, phosphatidylinositol 3-kinase and DNA topoisomerases that exhibit the importance of flavonoid-protein interaction. This study was designed to examine the interaction of human serum albumin (HSA) with quercetin (que), kaempferol (kae) and delphinidin (del) in aqueous solution at physiological conditions, using constant protein concentration of 0.25 mM (final) and various drug contents of 1 μM-1 mM. FTIR and UV-vis spectroscopic methods were used to determine the polyphenolic binding mode, the binding constant and the effects of flavonoid complexation on protein secondary structure. The spectroscopic results showed that flavonoids are located along the polypeptide chains through H-bonding interactions with overall affinity constant of Kque = 1.4 × 10 4 M -1, Kkae = 2.6 × 10 5 M -1 and Kdel = 4.71 × 10 5 M -1. The protein secondary structure showed no alterations at low pigment concentration (1 μM), whereas at high flavonoid content (1 mM), major reduction of α-helix from 55% (free HSA) to 42-46% and increase of β-sheet from 15% (free HSA) to 17-19% and β-anti from 7% (free HSA) to 10-20% occurred in the flavonoid-HSA adducts. The major reduction of HSA α-helix is indicative of a partial protein unfolding upon flavonoid interaction.

Unveiling the stimulatory effects of tartrazine on human and bovine serum albumin fibrillogenesis: Spectroscopic and microscopic study

Science.gov (United States)

Al-Shabib, Nasser Abdulatif; Khan, Javed Masood; Alsenaidy, Mohammad A.; Alsenaidy, Abdulrahman M.; Khan, Mohd Shahnawaz; Husain, Fohad Mabood; Khan, Mohammad Rashid; Naseem, Mohammad; Sen, Priyankar; Alam, Parvez; Khan, Rizwan Hasan

2018-02-01

Amyloid fibrils are playing key role in the pathogenesis of various neurodegenerative diseases. Generally anionic molecules are known to induce amyloid fibril in several proteins. In this work, we have studied the effect of anionic food additive dye i.e., tartrazine (TZ) on the amyloid fibril formation of human serum albumins (HSA) and bovine serum albumin (BSA) at pHs 7.4 and 3.5. We have employed various biophysical methods like, turbidity measurements, Rayleigh Light Scattering (RLS), Dynamic Light Scattering (DLS), intrinsic fluorescence, Congo red assay, far-UV CD, transmission electron microscopy (TEM) and atomic force microscopy (AFM) to decipher the mechanism of TZ-induce amyloid fibril formation in both the serum albumins at pHs 7.4 and 3.5. The obtained results suggest that both the albumins forms amyloid-like aggregates in the presence of 1.0 to 15.0 mM of TZ at pH 3.5, but no amyloid fibril were seen at pH 7.4. The possible cause of TZ-induced amyloid fibril formation is electrostatic and hydrophobic interaction because sulfate group of TZ may have interacted electrostatically with positively charged amino acids of the albumins at pH 3.5 and increased protein-protein and protein-TZ interactions leading to amyloid fibril formation. The TEM, RLS and DLS results are suggesting that BSA forms bigger size amyloids compared to HSA, may be due to high surface hydrophobicity of BSA.

Podocytes Degrade Endocytosed Albumin Primarily in Lysosomes

Science.gov (United States)

Carson, John M.; Okamura, Kayo; Wakashin, Hidefumi; McFann, Kim; Dobrinskikh, Evgenia; Kopp, Jeffrey B.; Blaine, Judith

2014-01-01

Albuminuria is a strong, independent predictor of chronic kidney disease progression. We hypothesize that podocyte processing of albumin via the lysosome may be an important determinant of podocyte injury and loss. A human urine derived podocyte-like epithelial cell (HUPEC) line was used for in vitro experiments. Albumin uptake was quantified by Western blot after loading HUPECs with fluorescein-labeled (FITC) albumin. Co-localization of albumin with lysosomes was determined by confocal microscopy. Albumin degradation was measured by quantifying FITC-albumin abundance in HUPEC lysates by Western blot. Degradation experiments were repeated using HUPECs treated with chloroquine, a lysosome inhibitor, or MG-132, a proteasome inhibitor. Lysosome activity was measured by fluorescence recovery after photo bleaching (FRAP). Cytokine production was measured by ELISA. Cell death was determined by trypan blue staining. In vivo, staining with lysosome-associated membrane protein-1 (LAMP-1) was performed on tissue from a Denys-Drash trangenic mouse model of nephrotic syndrome. HUPECs endocytosed albumin, which co-localized with lysosomes. Choloroquine, but not MG-132, inhibited albumin degradation, indicating that degradation occurs in lysosomes. Cathepsin B activity, measured by FRAP, significantly decreased in HUPECs exposed to albumin (12.5% of activity in controls) and chloroquine (12.8%), and declined further with exposure to albumin plus chloroquine (8.2%, palbumin and chloroquine alone, and these effects were potentiated by exposure to albumin plus chloroquine. Compared to wild-type mice, glomerular staining of LAMP-1 was significantly increased in Denys-Drash mice and appeared to be most prominent in podocytes. These data suggest lysosomes are involved in the processing of endocytosed albumin in podocytes, and lysosomal dysfunction may contribute to podocyte injury and glomerulosclerosis in albuminuric diseases. Modifiers of lysosomal activity may have therapeutic

Femtosecond laser-plasma interaction with prepulse-generated liquid metal microjets

International Nuclear Information System (INIS)

Uryupina, D. S.; Ivanov, K. A.; Savel'ev, A. B.; Volkov, R. V.; Brantov, A. V.; Bychenkov, V. Yu.; Povarnitsyn, M. E.; Tikhonchuk, V. T.

2012-01-01

Ultrashort laser pulse interaction with a microstructured surface of a melted metal is a promising source of hard x-ray radiation. Microstructuring is achieved by a weak prepulse that produces narrow high-density microjets. As an x-ray source, the interaction of the main laser pulse with such jets is shown to be nearly two orders of magnitude more efficient than the interaction with ordinary metal targets. This paper presents the results of optical and x-ray studies of laser-plasma interaction physics under such conditions supported by numerical simulations of microjet formation and fast-electron generation.

Femtosecond laser-plasma interaction with prepulse-generated liquid metal microjets

Energy Technology Data Exchange (ETDEWEB)

Uryupina, D. S.; Ivanov, K. A.; Savel' ev, A. B.; Volkov, R. V. [Faculty of Physics and International Laser Center of M.V. Lomonosov Moscow State University, 119991 Moscow, Leninskie Gory (Russian Federation); Brantov, A. V.; Bychenkov, V. Yu. [P. N. Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow (Russian Federation); Povarnitsyn, M. E. [Joint Institute for High Temperatures, Russian Academy of Sciences, 125412 Moscow (Russian Federation); Tikhonchuk, V. T. [CELIA, University of Bordeaux - CNRS - CEA, 33405 Talence (France)

2012-01-15

Ultrashort laser pulse interaction with a microstructured surface of a melted metal is a promising source of hard x-ray radiation. Microstructuring is achieved by a weak prepulse that produces narrow high-density microjets. As an x-ray source, the interaction of the main laser pulse with such jets is shown to be nearly two orders of magnitude more efficient than the interaction with ordinary metal targets. This paper presents the results of optical and x-ray studies of laser-plasma interaction physics under such conditions supported by numerical simulations of microjet formation and fast-electron generation.

Time-dependent Enhanced Corrosion of Ti6Al4V in the Presence of H2O2 and Albumin.

Science.gov (United States)

Zhang, Yue; Addison, Owen; Yu, Fei; Troconis, Brendy C Rincon; Scully, John R; Davenport, Alison J

2018-02-16

There is increasing concern regarding the biological consequences of metal release from implants. However, the mechanisms underpinning implant surface degradation, especially in the absence of wear, are often poorly understood. Here the synergistic effect of albumin and H 2 O 2 on corrosion of Ti6Al4V in physiological saline is studied with electrochemical methods. It is found that albumin induces a time-dependent dissolution of Ti6Al4V in the presence of H 2 O 2 in physiology saline. Potentiostatic polarisation measurements show that albumin supresses dissolution in the presence of H 2 O 2 at short times (<24 h) but over longer time periods (120 h) it significantly accelerates corrosion, which is attributed to albumin-catalysed dissolution of the corrosion product layer resulting in formation of a thinner oxide film. Dissolution of Ti6Al4V in the presence of albumin and H 2 O 2 in physiological saline is also found to be dependent on potential: the titanium ion release rate is found to be higher (0.57 µg/cm 2 ) at a lower potential (90 mV), where the oxide capacitance and resistance inferred from Electrochemical Impedance Spectroscopy also suggests a less resistant oxide film. The study highlights the importance of using more realistic solutions, and considering behaviour over longer time periods when testing corrosion resistance of metallic biomaterials.

Deterministic Model for Rubber-Metal Contact Including the Interaction Between Asperities

NARCIS (Netherlands)

Deladi, E.L.; de Rooij, M.B.; Schipper, D.J.

2005-01-01

Rubber-metal contact involves relatively large deformations and large real contact areas compared to metal-metal contact. Here, a deterministic model is proposed for the contact between rubber and metal surfaces, which takes into account the interaction between neighboring asperities. In this model,

Studies on kinetics of albumin in uraemic patients on chronic haemodialysis: evidence of interstitial albumin wash-down

DEFF Research Database (Denmark)

Hildebrandt, P; Jensen, H A; Henriksen, Jens Henrik Sahl

1983-01-01

Albumin-kinetic studies were performed in nine uraemic patients without oedema on chronic haemodialysis and in seven normal controls in order to determine microvascular leakiness and thereby, during steady state, lymph drainage of albumin. Transvascular escape rate of albumin [TERalb i.......e. the fraction of intravascular mass (IVMalb) passing into, or returning from, the extravascular space per unit time] and the distribution ratio (DRalb) between IVMalb and total albumin mass were determined from intravenously injected radioiodinated serum albumin. Before haemodialysis, TERalb was significantly...... with respect to controls (mean 0 X 44, range 0 X 42-0 X 48, P less than 0 X 01), and the extravascular mass of albumin was significantly decreased (mean 27 X 9 mumol kg-1, range 14.1 - 41.2 v. mean 35.9, range 27.1 - 43.8, P less than 0.05). We interpret the results as to indicate increased transvascular...

Scavenger receptor-mediated recognition of maleyl bovine plasma albumin and the demaleylated protein in human monocyte macrophages

International Nuclear Information System (INIS)

Haberland, M.E.; Fogelman, A.M.

1985-01-01

Maleyl bovine plasma albumin competed on an equimolar basis with malondialdehyde low density lipoprotein (LDL) in suppressing the lysosomal hydrolysis of 125 I-labeled malondialdehyde LDL mediated by the scavenger receptor of human monocyte macrophages. Maleyl bovine plasma albumin, in which 94% of the amino groups were modified, exhibited an anodic mobility in agarose electrophoresis 1.7 times that of the native protein. Incubation of maleyl bovine plasma albumin at pH 3.5 regenerated the free amino groups and restored the protein to the same electrophoretic mobility as native albumin. Although ligands recognized by the scavenger receptor typically are anionic, the authors propose that addition of new negative charge achieved by maleylation, rather than directly forming the receptor binding site(s), induces conformational changes in albumin as a prerequisite to expression of the recognition domain(s). They conclude that the primary sequence of albumin, rather than addition of new negative charge, provides the recognition determinant(s) essential for interaction of maleyl bovine plasma albumin with the scavenger receptor

Long-range interactions between excited helium and alkali-metal atoms

KAUST Repository

Zhang, J.-Y.; Schwingenschlö gl, Udo; Shi, T.-Y.; Tang, L.-Y.; Yan, Z.-C.

2012-01-01

–5% in the coefficient C6, and 1–10% in the coefficients C8 and C10. The dispersion coefficients Cn for the interaction of He(2 1,3S) and He(2 1,3P) with the ground-state alkali-metal atoms and for the interaction of He(2 1,3S) with the alkali-metal atoms in their first

Graphene-metal interaction and its effect on the interface stability under ambient conditions

Energy Technology Data Exchange (ETDEWEB)

Dong, Aiyi; Fu, Qiang, E-mail: qfu@dicp.ac.cn; Wei, Mingming; Bao, Xinhe

2017-08-01

Highlights: • Graphene (Gr)/transition metal (TM: Fe, Co, Pt, and Au) interfaces form through TM intercalation at Gr/Ru(0001) surface. • Graphene-metal interaction strength follows the order of Ru ≈ Fe ≈ Co > Pt > Au. • Oxygen intercalation occurs at Gr/Fe, Gr/Co, Gr/Pt, and Gr/Ru interfaces but not at Gr/Au interface in air around 100 °C. - Abstract: Interaction between graphene (Gr) and metal plays an important role in physics and chemistry of graphene/metal interfaces. In this work, well-defined interfaces between graphene and transition metals (TMs) including Fe, Co, Pt, and Au were prepared through TM intercalation on Gr/Ru(0001) surface. The Gr-metal interaction was investigated using X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. We found that graphene interacts most strongly with Ru, Fe and Co and most weakly with Au, following the order of Ru ≈ Fe ≈ Co > Pt > Au. The Gr/Fe, Gr/Co, Gr/Pt, and Gr/Ru interfaces can be readily intercalated by oxygen when exposed to air and illuminated by an infrared lamp. In contrast, oxygen intercalation does not happen at the Gr/Au interface under the same condition. It is suggested that both Gr-metal interaction and oxygen adsorption on the underlying metal surface are critical in the oxygen intercalation and the Gr/metal interface stability.

Multi-spectroscopic and voltammetric evidences for binding, conformational changes of bovine serum albumin with thiamine.

Science.gov (United States)

Bagoji, Atmanand M; Gowda, Jayant I; Gokavi, Naveen M; Nandibewoor, Sharanappa T

2017-08-01

The interaction between thiamine hydrochloride (TA) and bovine serum albumin (BSA) was investigated by fluorescence, FTIR, UV-vis spectroscopic and cyclic voltammetric techniques under optimised physiological condition. The fluorescence intensity of BSA is gradually decreased upon addition of TA due to the formation of a BSA-TA complex. The binding parameters were evaluated and their behaviour at different temperatures was analysed. The quenching constants (K sv ) obtained were 2.6 × 10 4 , 2.2 × 10 4 and 2.0 × 10 4  L mol -1 at 288, 298 and 308 K, respectively. The binding mechanism was static-type quenching. The values of ΔH° and ΔS° were found to be 26.87 kJ mol -1 and 21.3 J K -1  mol -1 , and indicated that electrostatic interaction was the principal intermolecular force. The changes in the secondary structure of BSA upon interaction with TA were confirmed by synchronous and 3-D spectral results. Site probe studies reveal that TA is located in site I of BSA. The effects of some common metal ions on binding of BSA-TA complex were also investigated.

Interaction mode and nanoparticle formation of bovine serum albumin and anthocyanin in three buffer solutions

International Nuclear Information System (INIS)

Zhou, Rui; Dong, Xueyan; Song, Lanlan; Jing, Hao

2014-01-01

Investigation of interaction mode of bovine serum albumin (BSA) and anthocyanin (ACN) in different solutions will help us understand the interaction mechanism and functional change of bioactive small molecule and biomacromolecule. This study investigated the binding mode, including binding constant, number of binding sites, binding force of BSA and ACN interaction in three buffer solutions of phosphate (PBS), sodium chloride (NaCl), and PBS-NaCl, using fluorescence spectroscopy and synchronous fluorescence spectroscopy. Formation and characteristics of BSA–ACN complex were also investigated using dynamic light scattering (DLS) and transmission electron microscopy (TEM). The results showed that ACN could interact with BSA at both tyrosine (Tyr) and tryptophan (Trp) residues through both hydrogen bonds and van der Waals force, and the same binding mode was seen in dH 2 O and three buffer solutions. The value of binding constant K was decreased as the temperature increased from 298 K to 308 K, and the decreasing degree was in the order of dH 2 O (9.0×10 4 )>NaCl (2.64×10 4 )/PBS (2.37×10 4 )>PBS-NaCl (0.88×10 4 ), which was inversely correlated with the ionic strength of the buffer solutions of PBS-NaCl>NaCl>PBS. It indicated that stability of BSA–ACN complex was affected most in dH 2 O than in three buffer solutions. The BSA and ACN interaction led to formation of BSA–ACN nanoparticles. The sizes of BSA–ACN nanoparticles in dH 2 O were smaller than that in three buffer solutions, which correlated with stronger binding force between BSA and ACN in dH 2 O than in three buffer solutions at room temperature (25 °C, 298 K). - Highlights: • We report the influences of four solutions on the BSA–ACN interaction. • We report the relationship between BSA–ACN interaction and particle size of complex. • The stability of BSA–ACN complex was affected most in dH 2 O than in buffer solutions

Interaction mechanisms of ionic liquids [Cnmim]Br (n=4, 6, 8, 10) with bovine serum albumin

International Nuclear Information System (INIS)

Yan Hua; Wu Junyong; Dai Guoliang; Zhong Aiguo; Chen Hao; Yang Jianguo; Han Deman

2012-01-01

It is important to study the interaction of ionic liquids (ILs) with protein for the applications of ILs in biochemical process, and help the researchers to choose and design the better ILs to serve as a solvent. In this work, the interaction between 1-alkyl-3-methylimidazolium bromide [C n mim]Br (n=4, 6, 8, 10) and bovine serum albumin (BSA) was systematically investigated for the first time by multi-spectroscopic approach (fluorescence, UV–vis and FT-IR spectroscopy) and density functional theory (DFT). [C n mim]Br (n=4, 6, 8, 10) can bind to BSA by H-bond interaction between their cationic headgroups and Asp/Glu amino acid residue at the surface of BSA, and hydrophobic interaction between their hydrocarbon chains and the hydrophobic amino acid residues in the interior of BSA. On the basis of thermodynamic parameters and the similar structure of [C n mim]Br (n=4, 6, 8, 10), it can be inferred that the hydrophobic interaction plays a major role in the interaction of [C 10 mim]Br with BSA, while the hydrogen bond and van der Waals force play a major role in the interaction of [C n mim]Br (n=4, 6, 8) with BSA. Synchronous fluorescence and FT-IR spectra indicate that [C 10 mim]Br could markedly change the secondary structure of BSA, while [C n mim]Br (n=4, 6, 8) could slightly change the secondary structure of BSA. The results allowed us to understand (i) the effect of the alkyl chain length of the cation on the mechanism of ILs–protein interaction and (ii) the effect of the alkyl chain length of the cation on the protein secondary structure. - Highlights: ► Interaction of [C n mim]Br with BSA was investigated by spectroscopy and DFT. ► Interaction mechanisms and BSA secondary structure were discussed. ► Effects of the alkyl chain length of cation were presented.

Albumin modification and fragmentation in renal disease.

Science.gov (United States)

Donadio, Carlo; Tognotti, Danika; Donadio, Elena

2012-02-18

Albumin is the most important antioxidant substance in plasma and performs many physiological functions. Furthermore, albumin is the major carrier of endogenous molecules and exogenous ligands. This paper reviews the importance of post-translational modifications of albumin and fragments thereof in patients with renal disease. First, current views and controversies on renal handling of proteins, mainly albumin, will be discussed. Post-translational modifications, namely the fragmentation of albumin found with proteomic techniques in nephrotic patients, diabetics, and ESRD patients will be presented and discussed. It is reasonable to hypothesize that proteolytic fragmentation of serum albumin is due to a higher susceptibility to proteases, induced by oxidative stress. The clinical relevance of the fragmentation of albumin has not yet been established. These modifications could affect some physiological functions of albumin and have a patho-physiological role in uremic syndrome. Proteomic analysis of serum allows the identification of over-expressed proteins and can detect post-translational modifications of serum proteins, hitherto hidden, using standard laboratory techniques. Copyright © 2011 Elsevier B.V. All rights reserved.

Solution behaviour of Human Serum Albumin and GLP-1variants

DEFF Research Database (Denmark)

Sønderby, Pernille

interaction is critical for the long term stability of a pharmaceutical. Protein complex formation is important for extended half-life in vivo and is essential to cellular communication such as the induction of the insulin response. This thesis focuses on human serum albumin (HSA) as a central player...

21 CFR 640.80 - Albumin (Human).

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Albumin (Human). 640.80 Section 640.80 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) BIOLOGICS ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Albumin (Human) § 640.80 Albumin (Human). (a) Proper...

The interaction between 4-aminoantipyrine and bovine serum albumin: Multiple spectroscopic and molecular docking investigations

International Nuclear Information System (INIS)

Teng Yue; Liu Rutao; Li Chao; Xia Qing; Zhang Pengjun

2011-01-01

4-Aminoantipyrine (AAP) is widely used in the pharmaceutical industry, in biochemical experiments and in environmental monitoring. AAP as an aromatic pollutant in the environment poses a great threat to human health. To evaluate the toxicity of AAP at the protein level, the effects of AAP on bovine serum albumin (BSA) were investigated by multiple spectroscopic techniques and molecular modeling. After the inner filter effect was eliminated, the experimental results showed that AAP effectively quenched the intrinsic fluorescence of BSA via static quenching. The number of binding sites, the binding constant, the thermodynamic parameters and binding subdomain were measured, and indicated that AAP could spontaneously bind with BSA on subdomain IIIA through electrostatic forces. Molecular docking results revealed that AAP interacted with the Glu 488 and Glu 502 residues of BSA. Furthermore, the conformation of BSA was demonstrably changed in the presence of AAP. The skeletal structure of BSA loosened, exposing internal hydrophobic aromatic ring amino acids and peptide strands to the solution.

Interaction with bovine serum albumin of an anti-oxidative pectic arabinogalactan from Andrographis paniculata.

Science.gov (United States)

Chatterjee, Udipta R; Ray, Sayani; Micard, Valérie; Ghosh, Debjani; Ghosh, Kanika; Bandyopadhyay, Shruti S; Ray, Bimalendu

2014-01-30

A pectic arabinogalactan was obtained from the leaves of Andrographis paniculata by aqueous extraction followed by α-amylase treatment, deproteination, and anion exchange chromatography. Methylation analysis, Smith degradation, and NMR spectroscopy indicated that it was a highly branched arabinogalactan containing a (1→3)-linked β-d-Galp main chain, substituted at O-6 by (1→6)-linked β-d-Galp side chains. The latter residues were substituted at O-3 by (1→5)- and (1→3)-linked α-l-Araf chains, and non reducing end-units of α-l-Araf and β-d-Galp. This homogeneous arabinogalactan (36 kDa), which contained phenolic acids, showed dose-dependent anti-oxidative properties. The phenolic acid moieties might be the functional sites. This arabinogalactan can form a complex with bovine serum albumin having binding constant K=6.48 × 10(6)/M. Thus, this study is an important step forward to investigate the involvement of arabinogalactan in processes including interaction with biologically important transport proteins. Copyright © 2013 Elsevier Ltd. All rights reserved.

The Effect of Albumin on MRP2 and BCRP in the Vesicular Transport Assay.

Directory of Open Access Journals (Sweden)

Feng Deng

Full Text Available The ABC transporters multidrug resistance associated protein 2 (MRP2 and breast cancer resistance protein (BCRP are of interest in drug development, since they affect the pharmacokinetics of several drugs. Membrane vesicle transport assays are widely used to study interactions with these proteins. Since albumin has been found to affect the kinetics of metabolic enzymes in similar membrane preparations, we investigated whether albumin affects the kinetic parameters of efflux transport. We found that albumin increased the Vmax of 5(6-carboxy-2',7'-dichlorofluorescein (CDCF and estradiol-17-β-D-glucuronide uptake into MRP2 vesicles in the presence of 0.1% bovine serum albumin (BSA by 2 and 1.5-fold, respectively, while BSA increased Lucifer yellow uptake by 30% in BCRP vesicles. Km values increased slightly, but the change was not statistically significant. The effect of BSA on substrate uptake was dependent on the vesicle amount, while increasing BSA concentration did not significantly improve substrate uptake. These results indicate a minor effect of albumin on MRP2 and BCRP, but it should be considered if albumin is added to transporter assays for example as a solubilizer, since the effect may be substrate or transporter specific.

Thermodynamic study of the effects of ethanol on the interaction of ochratoxin A with human serum albumin

Energy Technology Data Exchange (ETDEWEB)

Li, Yin [Department of General and Physical Chemistry, University of Pécs, Ifjúság 6, H-7624 Pécs (Hungary); János Szentágothai Research Center, Ifjúság 20, H-7624 Pécs (Hungary); Czibulya, Zsuzsanna [Department of General and Physical Chemistry, University of Pécs, Ifjúság 6, H-7624 Pécs (Hungary); János Szentágothai Research Center, Ifjúság 20, H-7624 Pécs (Hungary); Chimie et Biologie des Membranes et Nanoobjets, CNRS-Université de Bordeaux, UMR 52478, ENITAB, Pessac (France); Poór, Miklós [Institute of Laboratory Medicine, University of Pécs, Ifjúság 13, H-7624, Pécs (Hungary); Lecomte, Sophie [Chimie et Biologie des Membranes et Nanoobjets, CNRS-Université de Bordeaux, UMR 52478, ENITAB, Pessac (France); Kiss, László [Department of General and Physical Chemistry, University of Pécs, Ifjúság 6, H-7624 Pécs (Hungary); János Szentágothai Research Center, Ifjúság 20, H-7624 Pécs (Hungary); and others

2014-04-15

Ethanol effect on the interaction of ochratoxin A (OTA) with human serum albumin (HSA) was investigated by using fluorescence spectroscopy and Raman spectroscopy. The Raman results showed that after the binding of OTA, the microenvironment of tryptophan residue on HSA became less hydrophobic. The fluorescence quenching observations revealed that the binding constant for the binding of OTA to HSA decreased as ethanol concentration increased. The thermodynamic studies showed that the binding process of OTA to HSA switched from being entropy-driven to enthalpy-driven in the presence of increasing concentrations (0.7–24.7%, vol/vol) of ethanol. Enthalpy–entropy compensation effect for the binding of OTA to HSA in the presence of different ethanol concentrations had been found. Based on the thermodynamic analyses, we concluded that the ethanol-induced variation of the shape of binding site of OTA on HSA and the solvent reorganization surrounding the OTA–HSA complex are the two dominant effects. -- Highlights: • The presence of ethanol can prohibit the binding of OTA to HSA. • Microenvironment of Trp214 on HSA becomes less hydrophobic after the binding of OTA. • Ethanol induces the interaction from being entropy-driven to enthalpy-driven. • Enthalpy–entropy compensation for the interaction was found.

Probing into the binding interaction between medroxyprogesterone acetate and bovine serum albumin (BSA): spectroscopic and molecular docking methods.

Science.gov (United States)

Fang, Fang; Pan, Dong-Qi; Qiu, Min-Jie; Liu, Ting-Ting; Jiang, Min; Wang, Qi; Shi, Jie-Hua

2016-09-01

To further understand the mechanism of action and pharmacokinetics of medroxyprogesterone acetate (MPA), the binding interaction of MPA with bovine serum albumin (BSA) under simulated physiological conditions (pH 7.4) was studied using fluorescence emission spectroscopy, synchronous fluorescence spectroscopy, circular dichroism and molecular docking methods. The experimental results reveal that the fluorescence of BSA quenches due to the formation of MPA-BSA complex. The number of binding sites (n) and the binding constant for MPA-BSA complex are ~1 and 4.6 × 10(3)  M(-1) at 310 K, respectively. However, it can be concluded that the binding process of MPA with BSA is spontaneous and the main interaction forces between MPA and BSA are van der Waals force and hydrogen bonding interaction due to the negative values of ΔG(0) , ΔH(0) and ΔS(0) in the binding process of MPA with BSA. MPA prefers binding on the hydrophobic cavity in subdomain IIIA (site II'') of BSA resulting in a slight change in the conformation of BSA, but BSA retaining the α-helix structure. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Biophysical and molecular docking insight into the interaction of cytosine β-D arabinofuranoside with human serum albumin

International Nuclear Information System (INIS)

Alam, Parvez; Chaturvedi, Sumit Kumar; Anwar, Tamanna; Siddiqi, Mohammad Khursheed; Ajmal, Mohd Rehan; Badr, Gamal; Mahmoud, Mohamed H.; Hasan Khan, Rizwan

2015-01-01

Interaction of pharmacologically important anticancer drug cytosine β-D arabinofuranoside with human serum albumin (HSA) at physiological pH 7.4 has been studied by utilizing various spectroscopic and molecular docking strategies. Fluorescence results revealed that cytosine β-D arabinofuranoside interacts with HSA through static quenching mechanism with binding affinity of 2.4×10 3 M −1 . The average binding distance between drug and Trp 214 of HSA was found to be 2.23 nm on the basis of the theory of Förster's energy transfer. Synchronous fluorescence data indicated that interaction of drug with HSA changed the microenvironment around the tryptophan residue. UV–visible spectroscopy and circular dichroism results deciphered the complex formation and conformational alterations in the HSA respectively. Dynamic light scattering was utilized to understand the topology of protein in absence and presence of drug. Thermodynamic parameters obtained from isothermal titration calorimetry (ΔH=−26.01 kJ mol −1 and TΔS=6.5 kJ mol −1 ) suggested the involvement of van der Waal interaction and hydrogen bonding. Molecular docking and displacement study with site specific markers suggested that cytosine β-D arabinofuranoside binds to subdomain IB of HSA which is also known as the hemin binding site. This study will be helpful to understand the binding mechanism of cytosine β-D arabinofuranoside with HSA and associated alterations. - Highlights: • Comprehensive insight into the interaction of CBDA with HSA. • The interaction process is spontaneous and exothermic. • The main governing forces for stabilizing HSA–CBDA complex are van der Waal interaction and hydrogen bonding. • CBDA binds at subdomain IB on HSA

Albumin grafting on polymer surfaces by gamma-irradiation

International Nuclear Information System (INIS)

Kamath, K.R.; Park, K.; DeMeo, D.

1993-01-01

Polymeric biomaterial surfaces were modified by albumin grafting to improve their blood compatibility. Albumin molecules were functionalized by introduction of double bonds. The functionalized albumin was covalently attached to polypropylene fibers, polycarbonate, and poly(vinyl chloride) by gamma-irradiation. ESCA and ATR/FTIR analysis of the control and grafted surfaces was conducted. Albumin grafting efficiency was found to be dependent on the gamma-irradiation time and the concentration of albumin as indicated by platelet adhesion studies. The grafted albumin molecules were not displaced when exposed to blood for prolonged time period. Finally, PLEXUS oxygenators grafted with albumin using this approach showed a significant reduction in platelet adhesion when compared to control

Influence of oxygen, albumin and pH on copper dissolution in a simulated uterine fluid.

Science.gov (United States)

Bastidas, D M; Cano, E; Mora, E M

2005-06-01

The aim of this paper is to study the influence of albumin content, from 5 to 45 g/L, on copper dissolution and compounds composition in a simulated uterine solution. Experiments were performed in atmospheric pressure conditions and with an additional oxygen pressure of 0.2 atmospheres, at 6.3 and 8.0 pH values, and at a temperature of 37 +/- 0.1 degrees C for 1, 3, 7, and 30 days experimentation time. The copper dissolution rate has been determined using absorbance measurements, finding the highest value for pH 8.0, 35 g/L albumin, and with an additional oxygen pressure of 0.2 atmospheres: 674 microg/day for 1 day, and 301 microg/day for 30 days. X-ray photoelectron spectroscopy (XPS) results show copper(II) as the main copper oxidation state at pH 8.0; and copper(I) and metallic copper at pH 6.3. The presence of albumin up to 35 g/L, accelerates copper dissolution. For high albumin content a stabilisation on the copper dissolution takes place. Corrosion product layer morphology is poorly protective, showing paths through which copper ions can release.

Combined molecular docking and multi-spectroscopic investigation on the interaction between Eosin B and human serum albumin

Energy Technology Data Exchange (ETDEWEB)

Yang Qing; Zhou Ximin [National Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000 (China); Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Chen Xingguo, E-mail: chenxg@lzu.edu.c [National Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000 (China); Department of Chemistry, Lanzhou University, Lanzhou 730000 (China)

2011-04-15

The binding of Eosin B to human serum albumin (HSA) was studied using molecular docking, fluorescence, UV-vis, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy. The mechanism of interaction between Eosin B and HSA in terms of the binding parameters, the thermodynamic functions and the effect of Eosin B on the conformation of HSA were investigated. Protein-ligand docking study indicated that Eosin B bound to residues located in the subdomain IIA of HSA and Eosin B-HSA complex was stabilized by hydrophobic force and hydrogen bonding. In addition, fluorescence data revealed that Eosin B strongly quenched the intrinsic fluorescence of HSA through a static quenching procedure. Furthermore, alteration of the secondary structure of HSA in the presence of the dye was conformed by UV-vis, FT-IR and CD spectroscopy.

Combined molecular docking and multi-spectroscopic investigation on the interaction between Eosin B and human serum albumin

International Nuclear Information System (INIS)

Yang Qing; Zhou Ximin; Chen Xingguo

2011-01-01

The binding of Eosin B to human serum albumin (HSA) was studied using molecular docking, fluorescence, UV-vis, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy. The mechanism of interaction between Eosin B and HSA in terms of the binding parameters, the thermodynamic functions and the effect of Eosin B on the conformation of HSA were investigated. Protein-ligand docking study indicated that Eosin B bound to residues located in the subdomain IIA of HSA and Eosin B-HSA complex was stabilized by hydrophobic force and hydrogen bonding. In addition, fluorescence data revealed that Eosin B strongly quenched the intrinsic fluorescence of HSA through a static quenching procedure. Furthermore, alteration of the secondary structure of HSA in the presence of the dye was conformed by UV-vis, FT-IR and CD spectroscopy.

Surface/structure functionalization of copper-based catalysts by metal-support and/or metal–metal interactions

Energy Technology Data Exchange (ETDEWEB)

Konsolakis, Michalis, E-mail: mkonsol@science.tuc.gr [School of Production Engineering and Management, Technical University of Crete, GR-73100 Chania, Crete (Greece); Ioakeimidis, Zisis [Department of Mechanical Engineering, University of Western Macedonia, Bakola and Sialvera, GR-50100 Kozani (Greece)

2014-11-30

Highlights: • The surface chemistry of Cu-based catalysts is adjusted by metal-support or metal–metal interactions. • Three series of catalysts, i.e., Cu/REOs, Cu/Ce{sub 1−x}Sm{sub x}O{sub δ} and Cu–Co/CeO{sub 2} were prepared. • The local structure of Cu sites is remarkably affected by support or active phase modification. • Useful insights toward the fundamental understanding of Cu-catalyzed reactions are provided. - Abstract: Cu-based catalysts have recently attracted great attention both in catalysis and electro-catalysis fields due to their excellent catalytic performance and low cost. Given that their performance is determined, to a great extent, by Cu sites local environment, considerable efforts have been devoted on the strategic modifications of the electronic and structural properties of Cu sites. In this regard, the feasibility of tuning the local structure of Cu entities by means of metal-support or metal–metal interactions is investigated. More specifically, the physicochemical properties of Cu entities are modified by employing: (i) different oxides (CeO{sub 2}, La{sub 2}O{sub 3}, Sm{sub 2}O{sub 3}), or (ii) ceria-based mixed oxides (Ce{sub 1−x}Sm{sub x}O{sub δ}) as supporting carriers, and (iii) a second metal (Cobalt) adjacent to Cu (bimetallic Cu–Co/CeO{sub 2}). A characterization study, involving BET, XRD, TPR, and XPS, reveal that significant modifications on structural, redox and electronic properties of Cu sites can be induced by adopting either different oxide carriers or bimetallic complexes. Fundamental insights into the tuning of Cu local environment by metal-support or metal–metal interactions are provided, paving the way for real-life industrial applications.

Renal albumin absorption in physiology and pathology.

Science.gov (United States)

Birn, H; Christensen, E I

2006-02-01

Albumin is the most abundant plasmaprotein serving multiple functions as a carrier of metabolites, hormones, vitamins, and drugs, as an acid/base buffer, as antioxidant and by supporting the oncotic pressure and volume of the blood. The presence of albumin in urine is considered to be the result of the balance between glomerular filtration and tubular reabsorption. Albuminuria has been accepted as an independent risk factor and a marker for renal as well as cardiovascular disease, and during the past decade, evidence has suggested that albumin itself may cause progression of renal disease. Thus, the reduction of proteinuria and, in particular, albuminuria has become a target in itself to prevent deterioration of renal function. Studies have shown albumin and its ligands to induce expression of inflammatory and fibrogenic mediators, and it has been hypothesized that increased filtration of albumin causes excessive tubular reabsorption, resulting in inflammation and fibrosis, resulting in the loss of renal function. In addition, it is known that tubular dysfunction in itself may cause albuminuria owing to decreased reabsorption of filtered albumin, and, recently, it has been suggested that significant amounts of albumin fragments are excreted in the urine as a result of tubular degradation. Thus, although both tubular and glomerular dysfunction influences renal handling of albumin, it appears that tubular reabsorption plays a central role in mediating the effects of albumin on renal function. The present paper will review the mechanisms for tubular albumin uptake and the possible implications for the development of renal disease.

Preparation of 99m Tc-Macroaggregated albumin for lung perfusion studies

International Nuclear Information System (INIS)

Alfonso Marin, Yumisley; Zayas Crespo, Francisco I.; Mesa Duennas Niurka; Hernandez Gonzalez, Ignacio; Leon Perez, Mariela; Rivero Santamaria, Alejandro

2009-01-01

The present paper shows the design, optimization, quality control for testing radiochemical purity, biological quality and realtime stability studies of a preparation of macroaggregated albumin from the controlled denaturation of HSA. An experimental design with a 2 3 factorial plan was carried out in order to determine the ideal conditions for the preparation. The results showed that variations of albumin concentrations within the range of 515 mg/mL were irrelevant, however, the final pH of the mixture and the stirring speed were significant variables, as well as their interaction. Formulations with particles of diameter between 11 and 80 μ were obtained with the conditions selected in the experimental design which met the internationally established criteria for radiochemical purity, sterility and apyrogenicity. The biodistribution in experimental animals showed good quality lung images. The produced lots maintained physical, radiochemical, biological and microbiological stability during 90 days of storage at 4 o C. Key words: albumins, blood serum, emboli, labelling, lungs, quality control, radiopharmaceuticals, thrombosis, technetium 99. (author)

Molecular displacement of warfarin from human serum albumin by flavonoid aglycones

International Nuclear Information System (INIS)

Poór, Miklós; Li, Yin; Kunsági-Máté, Sándor; Petrik, József; Vladimir-Knežević, Sanda; Kőszegi, Tamás

2013-01-01

The well-known 4-hydroxycoumarin derivative warfarin is a widespread anticoagulant drug. Besides its strong albumin binding property warfarin has a narrow therapeutic window. Therefore, a few percent of displacement from albumin can result in serious biological consequences. The flavonoid molecular group also shows very strong plasma albumin binding characteristics occupying the same binding site. It is plausible to hypothesize that flavonoid aglycones may be able to displace warfarin from human serum albumin (HSA). In our study the competing activities of different flavone (acacetin, apigenin, chrysin, luteolin), flavonol (galangin, quercetin) and flavanone (hesperetin, naringenin) aglycones were investigated using fluorescence spectroscopy. Our results represent that flavonoids are able to displace warfarin from the surface of HSA. On the other hand, when comparing flavone or flavonol groups to flavanones the latter group seems to be much weaker competitor. These observations were also supported by calculation of stability constants. Our investigations strongly suggest that we should reckon with the described molecular displacement. However, further in vivo studies are needed to support the findings of our model system. -- Highlights: • Various flavonoids are able to displace warfarin from human serum albumin. • Flavones and flavonols are much more effective competitors than flavanones. • Even 300 nM aglycone concentrations show the interaction with 3 μM warfarin. • Flavonoid pairs show quasi-additive desorbing property. • Flavones and flavonols are much stronger competitors than the examined drugs

Molecular displacement of warfarin from human serum albumin by flavonoid aglycones

Energy Technology Data Exchange (ETDEWEB)

Poór, Miklós [Institute of Laboratory Medicine, University of Pécs, Pécs H-7624 (Hungary); Li, Yin; Kunsági-Máté, Sándor [Department of General and Physical Chemistry, University of Pécs, Pécs H-7624 (Hungary); János Szentágothai Research Center, H-7624 Pécs (Hungary); Petrik, József [Department of Medical Biochemistry and Hematology, Faculty of Pharmacy and Biochemistry, University of Zagreb, HR-10000 Zagreb (Croatia); Vladimir-Knežević, Sanda [Department of Pharmacognosy, Faculty of Pharmacy and Biochemistry, University of Zagreb, HR-10000 Zagreb (Croatia); Kőszegi, Tamás, E-mail: koszegit@freemail.hu [Institute of Laboratory Medicine, University of Pécs, Pécs H-7624 (Hungary)

2013-10-15

The well-known 4-hydroxycoumarin derivative warfarin is a widespread anticoagulant drug. Besides its strong albumin binding property warfarin has a narrow therapeutic window. Therefore, a few percent of displacement from albumin can result in serious biological consequences. The flavonoid molecular group also shows very strong plasma albumin binding characteristics occupying the same binding site. It is plausible to hypothesize that flavonoid aglycones may be able to displace warfarin from human serum albumin (HSA). In our study the competing activities of different flavone (acacetin, apigenin, chrysin, luteolin), flavonol (galangin, quercetin) and flavanone (hesperetin, naringenin) aglycones were investigated using fluorescence spectroscopy. Our results represent that flavonoids are able to displace warfarin from the surface of HSA. On the other hand, when comparing flavone or flavonol groups to flavanones the latter group seems to be much weaker competitor. These observations were also supported by calculation of stability constants. Our investigations strongly suggest that we should reckon with the described molecular displacement. However, further in vivo studies are needed to support the findings of our model system. -- Highlights: • Various flavonoids are able to displace warfarin from human serum albumin. • Flavones and flavonols are much more effective competitors than flavanones. • Even 300 nM aglycone concentrations show the interaction with 3 μM warfarin. • Flavonoid pairs show quasi-additive desorbing property. • Flavones and flavonols are much stronger competitors than the examined drugs.

99mTc-albumin can replace 125I-albumin to determine plasma volume repeatedly

DEFF Research Database (Denmark)

Bonfils, Peter K; Damgaard, Morten; Stokholm, Knud H

2012-01-01

OBJECTIVE: Plasma volume assessment may be of importance in several disorders. The purpose of the present study was to compare the reliability of plasma volume measurements by technetium-labeled human serum albumin ((99m)Tc-HSA) with a simultaneously performed plasma volume determination...... with iodine-labeled human serum albumin ((125)I-HSA). MATERIALS AND METHODS: In 15 healthy volunteers, simultaneous plasma volume measurements with (99m)Tc-HSA and (125)I-HSA were performed after ½ hour in the supine position. Blood samples were obtained 10, 15, 20, and 30 minutes after the injection...... for accurate retropolation from the plasma counts to time zero to correct for leakage of the isotopes from the circulation. RESULTS: The mean difference (bias) between plasma volume measured with (125)I-albumin and (99m)Tc-albumin was 8 ml (0.1 ml/kg) with limits of agreement (bias ±1.96 SD) ranging from -181...

Interaction of bovine serum albumin with a psychotropic drug alprazolam: Physicochemical, photophysical and molecular docking studies

Energy Technology Data Exchange (ETDEWEB)

Sarkar, Moumita; Paul, Shiv Shankar; Mukherjea, Kalyan K., E-mail: k_mukherjea@yahoo.com

2013-10-15

The interaction between alprazolam (Alp) and bovine serum albumin (BSA) has been investigated under physiological conditions by UV–vis, steady state as well as time-resolved fluorescence, circular dichroism (CD) spectroscopic and molecular docking studies. The binding constant K of Alp to BSA was found to be 1.8×10{sup 5} L mol{sup −1} from absorption data. Fluorometric studies suggested the formation of the Alp–BSA complex, while time-resolved fluorescence studies showed that the binding of Alp by BSA was mainly static and the effective rate constant is found to be 2.33×10{sup 13} L mol{sup −1} s{sup −1}. According to the modified Stern–Volmer equation, the Stern–Volmer quenching constants (K{sub SV}) between Alp and BSA at four different temperatures 295, 303, 308, 313 K were obtained to be 1.19×10{sup 5}, 1.05×10{sup 5}, 0.99×10{sup 5} and 0.90×10{sup 5} L mol{sup −1}, respectively. The change in enthalpy (ΔH) and entropy (ΔS) were calculated to be −11.66 and 57.64 J mol{sup −1} K{sup −1}, respectively, indicating that the interaction was hydrophobic in nature. Site marker competitive experiments suggested that the binding of Alp to BSA primarily took place in sub-domain IIA, whereas the binding distance (r) between Alp and the tryptophan residue of BSA was obtained to be 1.87 nm by Förster's theory of non-radiative energy transfer. The conformational studies by CD spectroscopy showed that the presence of Alp decreased the α-helical content of BSA and induced the unfolding of the polypeptide of the protein. The change in conformation was also supported by excitation–emission matrix spectroscopy (EEMS) studies. The molecular docking experiment supports the above results and effectively proves the binding of Alp to BSA. -- Highlights: • Alprazolam: a benzodiazepine drug with anxiolytic and anticonvulsant properties. • Alprazolam induces conformational change on the native as well as urea denatured BSA. • Alprazolam may

Characterization of the interactions of human serum albumin (HSA), gatifloxacin, and metronidazole using spectroscopic and electrochemical methods

International Nuclear Information System (INIS)

Fu, Li; Liu, Xiu-fen; Zhou, Qiu-xiang; Zhang, Ji-xiang; Dong, Jing-ya; Wang, Jian-fang

2014-01-01

Human serum albumin (HSA), the most abundant protein in blood plasma, is an important carrier for many drugs. Understanding HSA-drug interactions is critical in being able to interpret the distribution and acting mechanisms of these drugs, which is particularly important in the case of multi-drug therapy. In this study, we investigated the interactions between HSA and two commonly used antibiotics, gatifloxacin (GFLX) and metronidazole (MET), in Tris–HCl buffer solution (pH=7.4). The efficacy of the individual drugs (GFLX or MET) and the efficacy of a combination of GFLX and MET were measured using fluorescence spectroscopy, UV absorption spectroscopy, and electrochemical methods. Our results demonstrated that GFLX and MET have a synergistic effect. Briefly, one drug decreased the binding stability with HSA of the other drug, thus increasing the concentration of free drug at the action sites. The interaction of drugs with HSA is a process of complex-formation static quenching. There is approximately one binding site between HSA and the drug (GFLX or MET). The binding distance, r, between the drug and HSA was determined on the basis of the theory of Forster-type non-radiative energy transfer. It was shown that the interaction between the two drugs increased the r-value. Using thermodynamic parameters, we found that the binding of drug-HSA interactions is mainly controlled by electrostatic force. Analysis of the synchronous fluorescence spectrum suggested that the interactions between the drugs have important effects on protein conformation. In conclusion, combining GFLX and MET enhances treatment efficacy. Our study provides a basis to understand the mechanism of the interaction of MET, GFLX and HSA in the human body. - Highlights: • The synergistic effects between MET and GFLX were founed. • The type of interaction between the drugs and HSA was identified

Repression of the albumin gene in Novikoff hepatoma cells

International Nuclear Information System (INIS)

Capetanaki, Y.G.; Flytzanis, C.N.; Alonso, A.

1982-01-01

Novikoff hepatoma cells have lost their capacity to synthesize albumin. As a first approach to study the mechanisms underlying this event, in vitro translation in a reticulocyte system was performed using total polyadenylated mRNA from rat liver and Novikoff hepatoma cells. Immunoprecipitation of the in vitro translation products with albumin-specific antibody revealed a total lack of albumin synthesis in Novikoff hepatoma, suggesting the absence of functional albumin mRNA in these cells. Titration experiments using as probe albumin cDNA cloned in pBR322 plasmid demonstrated the absence of albumin-specific sequences in both polysomal and nuclear polyadenylated and total RNA from Novikoff cells. This albumin recombinant plasmid was obtained by screening a rat liver cDNA library with albumin [/sup 32/P]cDNA reverse transcribed from immuno-precipitated mRNA. The presence of an albumin-specific gene insert was documented with translation assays as well as by restriction mapping. Repression of the albumin gene at the transcriptional level was further demonstrated by RNA blotting experiments using the cloned albumin cDNA probe. Genomic DNA blots using the cloned albumin cDNA as probe did not reveal any large-scale deletions, insertions, or rearrangements in the albumin gene, suggesting that the processes involved in the suppression of albumin mRNA synthesis do not involve extensive genomic rearrangements

Binding interaction of ramipril with bovine serum albumin (BSA): Insights from multi-spectroscopy and molecular docking methods.

Science.gov (United States)

Shi, Jie-Hua; Pan, Dong-Qi; Jiang, Min; Liu, Ting-Ting; Wang, Qi

2016-11-01

The binding interaction between a typical angiotensin-converting enzyme inhibitor (ACEI), ramipril, and a transport protein, bovine serum albumin (BSA), was studied in vitro using UV-vis absorption spectroscopy, steady-state fluorescence spectroscopic titration, synchronous fluorescence spectroscopy, three dimensional fluorescence spectroscopy, circular dichroism and molecular docking under the imitated physiological conditions (pH=7.4). The experimental results suggested that the intrinsic fluorescence of BSA was quenched by ramipril thought a static quenching mechanism, indicating that the stable ramipril-BSA complex was formed by the intermolecular interaction. The number of binding sites (n) and binding constant of ramipril-BSA complex were about 1 and 3.50×10 4 M -1 at 298K, respectively, suggesting that there was stronger binding interaction of ramipril with BSA. The thermodynamic parameters together with molecular docking study revealed that both van der Waal's forces and hydrogen bonding interaction dominated the formation of the ramipril-BSA complex and the binding interaction of BSA with ramipril is enthalpy-driven processes due to |ΔH°|>|TΔS°| and ΔG°<0. The spatial distance between ramipril and BSA was calculated to be 3.56nm based on Förster's non-radiative energy transfer theory. The results of the competitive displacement experiments and molecular docking confirmed that ramipril inserted into the subdomain IIA (site I) of BSA, resulting in a slight change in the conformation of BSA but BSA still retained its secondary structure α-helicity. Copyright © 2016 Elsevier B.V. All rights reserved.

Fibrinogen adsorption on blocked surface of albumin.

Science.gov (United States)

Holmberg, Maria; Hou, Xiaolin

2011-05-01

We have investigated the adsorption of albumin and fibrinogen onto PET (polyethylene terephthalate) and glass surfaces and how pre-adsorption of albumin onto these surfaces can affect the adsorption of later added fibrinogen. For materials and devices being exposed to blood, adsorption of fibrinogen is often a non-wanted event, since fibrinogen is part of the clotting cascade and unspecific adsorption of fibrinogen can have an influence on the activation of platelets. Albumin is often used as blocking agent for avoiding unspecific protein adsorption onto surfaces in devices designed to handle biological samples, including protein solutions. It is based on the assumption that proteins adsorbs as a monolayer on surfaces and that proteins do not adsorb on top of each other. By labelling albumin and fibrinogen with two different radioactive iodine isotopes that emit gamma radiation with different energies, the adsorption of both albumin and fibrinogen has been monitored simultaneously on the same sample. Information about topography and coverage of adsorbed protein layers has been obtained using AFM (Atomic Force Microscopy) analysis in liquid. Our studies show that albumin adsorbs in a multilayer fashion on PET and that fibrinogen adsorbs on top of albumin when albumin is pre-adsorbed on the surfaces. Copyright © 2010 Elsevier B.V. All rights reserved.

Evaluation of the interactions between human serum albumin (HSA and warfarin or diflunisal by using molecular fluorescence using two approaches

Directory of Open Access Journals (Sweden)

Susana Amézqueta

2018-03-01

Full Text Available Serum albumin is the main drug transporter of the bloodstream and contains two main binding sites:  Sudlow I or acidic drug binding site, and Sudlow II or benzodiazepine binding site. Warfarin, a well-known anticoagulant drug commonly used in the prevention of thrombosis and thromboembolism, binds to Sudlow I site, whereas non-steroidal antiinflammatory drugs (NSAIDs such as diflunisal bind preferentially to Sudlow II site.  Albumin is a fluorophore that modifies its fluorescence (quenching or enhancement effect when it is bound to a drug. The application of the double logarithm Stern-Volmer equation allows the calculation of the stoichiometry and the binding constant of the process. This procedure does not consider the possible interferences coming from the fluorescence of the drug though. Another strategy to evaluate the binding constants is to consider the whole spectrum, taking into account all the possible species in equilibrium; in this case we have used an extended version of the STAR program, which can deal with 300 spectra, each containing up to 300 data points. The aim of this work is to compare both approaches to evaluate the interaction between warfarin (Sudlow I and diflunisal (Sudlow II and HSA: the double logarithm Stern-Volmer equation and the STAR program.

Interparticle interactions and structure in nonideal solutions of human serum albumin studied by small-angle neutron scattering and Monte Carlo simulation

DEFF Research Database (Denmark)

Sjöberg, B.; Mortensen, K.

1994-01-01

of human serum albumin (HSA) up to a concentration of 0.26 g/cm(3) in 1.08 M NaCl. In order to obtain a model for the interactions we have combined the SANS data with results obtained by Monte Carlo simulations where we calculate the structure factor S(Q) and the pair correlation function g......Moderately or highly concentrated nonideal solutions of macromolecules are very important systems e.g. in biology and in many technical processes. In this work we have used the small-angle neutron scattering technique (SANS) to study the interactions and interparticle structure in solutions......(r). The advantage of using the Monte Carlo method is that completely general models for the particle shape and the interactions can be considered. It is found that the SANS data can be explained by a model where the shape of the HSA molecule is approximated by an ellipsoid of revolution with semiaxes a = 6.8 nm...

Spectroscopic analyses and studies on respective interaction of cyanuric acid and uric acid with bovine serum albumin and melamine

Science.gov (United States)

Chen, Dandan; Wu, Qiong; Wang, Jun; Wang, Qi; Qiao, Heng

2015-01-01

In this work, the fluorescence quenching was used to study the interaction of cyanuric acid (CYA) and uric acid (UA) with bovine serum albumin (BSA) at two different temperatures (283 K and 310 K). The bimolecular quenching constant (Kq), apparent quenching constant (Ksv), effective binding constant (KA) and corresponding dissociation constant (KD), binding site number (n) and binding distance (r) were calculated by adopting Stern-Volmer, Lineweaver-Burk, Double logarithm and overlap integral equations. The results show that CYA and UA are both able to obviously bind to BSA, but the binding strength order is BSA + CYA < BSA + UA. And then, the interactions of CYA and UA with melamine (MEL) under the same conditions were also studied by using similar methods. The results indicates that both CYA and UA can bind together closely with melamine (MEL). It is wished that these research results would facilitate the understanding the formation of kidney stones and gout in the body after ingesting excess MEL.

Combined spectroscopies and molecular docking approach to characterizing the binding interaction of enalapril with bovine serum albumin.

Science.gov (United States)

Pan, Dong-Qi; Jiang, Min; Liu, Ting-Ting; Wang, Qi; Shi, Jie-Hua

2017-06-01

The binding interaction between bovine serum albumin (BSA) and enalapril (ENPL) at the imitated physiological conditions (pH = 7.4) was investigated using UV-vis absorption spectroscopy (UV-vis), fluorescence emission spectroscopy (FES), synchronous fluorescence spectroscopy (SFS), Fourier transform infrared spectroscopy (FT-IR), circular dichroism (CD) and molecular docking methods. It can be deduced from the experimental results from the steady-state fluorescence spectroscopic titration that the intrinsic BSA fluorescence quenching mechanism induced by ENPL is static quenching, based on the decrease in the BSA quenching constants in the presence of ENPL with increase in temperature and BSA quenching rates >10 10  L mol -1  sec -1 . This result indicates that the ENPL-BSA complex is formed through an intermolecular interaction of ENPL with BSA. The main bonding forces for interaction of BSA and ENPL are van der Waal's forces and hydrogen bonding interaction based on negative values of Gibbs free energy change (ΔG 0 ), enthalpic change (ΔH 0 ) and entropic change (ΔS 0 ). The binding of ENPL with BSA is an enthalpy-driven process due to |ΔH°| > |TΔS°| in the binding process. The results of competitive binding experiments and molecular docking confirm that ENPL binds in BSA sub-domain IIA (site I) and results in a slight change in BSA conformation, but BSA still retains its α-helical secondary structure. Copyright © 2016 John Wiley & Sons, Ltd.

Synchronous fluorescence based biosensor for albumin determination by cooperative binding of fluorescence probe in a supra-biomolecular host-protein assembly.

Science.gov (United States)

Patra, Digambara

2010-01-15

A synchronous fluorescence probe based biosensor for estimation of albumin with high sensitivity and selectivity was developed. Unlike conventional fluorescence emission or excitation spectral measurements, synchronous fluorescence measurement offered exclusively a new synchronous fluorescence peak in the shorter wavelength range upon binding of chrysene with protein making it an easy identification tool for albumin determination. The cooperative binding of a fluorescence probe, chrysene, in a supramolecular host-protein assembly during various albumin assessments was investigated. The presence of supramolecular host molecules such as beta-cyclodextrin, curucurbit[6]uril or curucurbit[7]uril have little influence on sensitivity or limit of detection during albumin determination but reduced dramatically interference from various coexisting metal ion quenchers/enhancers. Using the present method the limit of detection for BSA and gamma-Globulin was found to be 0.005 microM which is more sensitive than reported values. Copyright 2009 Elsevier B.V. All rights reserved.

Study on the molecular interaction of graphene quantum dots with human serum albumin: Combined spectroscopic and electrochemical approaches

Energy Technology Data Exchange (ETDEWEB)

Huang, Shan; Qiu, Hangna; Lu, Shuangyan; Zhu, Fawei [College of Chemistry and Material Science, Guangxi Teachers Education University, Nanning 530001 (China); Xiao, Qi, E-mail: qi.xiao@whu.edu.cn [College of Chemistry and Material Science, Guangxi Teachers Education University, Nanning 530001 (China); State Key Laboratory of Virology, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China)

2015-03-21

Highlights: • The interactions between GQDs and HSA were systematically investigated. • GQDs could quench the intrinsic fluorescence of HSA via static mode. • The binding site of GQDs was mainly located in site I of HSA. • The potential toxicity of GQDs resulted in the structural damage of HSA. - Abstract: Graphene quantum dots (GQDs) have attracted great attention in biological and biomedical applications due to their super properties, but their potential toxicity investigations are rarely involved. Since few studies have addressed whether GQDs could bind and alter the structure and function of human serum albumin (HSA), the molecular interaction between GQDs and HSA was systematically characterized by the combination of multispectroscopic and electrochemical approaches. GQDs could quench the intrinsic fluorescence of HSA via static mode. The competitive binding fluorescence assay revealed that the binding site of GQDs was site I of HSA. Some thermodynamic parameters suggested that GQDs interacted with HSA mainly through van der Waals interactions and hydrogen bonding interactions, and protonation might also participate in the process. As further revealed by FT-IR spectroscopy and circular dichroism technique, GQDs could cause the global and local conformational change of HSA, which illustrated the potential toxicity of GQDs that resulted in the structural damage of HSA. Electrochemical techniques demonstrated the complex formation between GQDs and HSA. Our results offered insights into the binding mechanism of GQDs with HSA and provided important information for possible toxicity risk of GQDs to human health.

Biophysical and molecular docking insight into the interaction of cytosine β-D arabinofuranoside with human serum albumin

Energy Technology Data Exchange (ETDEWEB)

Alam, Parvez; Chaturvedi, Sumit Kumar [Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, UP (India); Anwar, Tamanna [Center of Bioinformatics Research and Technology, Aligarh 202002 (India); Siddiqi, Mohammad Khursheed; Ajmal, Mohd Rehan [Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, UP (India); Badr, Gamal [Laboratory of Immunology & Molecular Physiology, Zoology Department, Faculty of Science, Assiut University, 71516 Assiut (Egypt); Mahmoud, Mohamed H. [Food Science and Nutrition Department, National Research Center, Dokki, Cairo (Egypt); Deanship of Scientific Research, King Saud University, Riyadh (Saudi Arabia); Hasan Khan, Rizwan, E-mail: rizwanhkhan@hotmail.com [Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, UP (India)

2015-08-15

Interaction of pharmacologically important anticancer drug cytosine β-D arabinofuranoside with human serum albumin (HSA) at physiological pH 7.4 has been studied by utilizing various spectroscopic and molecular docking strategies. Fluorescence results revealed that cytosine β-D arabinofuranoside interacts with HSA through static quenching mechanism with binding affinity of 2.4×10{sup 3} M{sup −1}. The average binding distance between drug and Trp{sup 214} of HSA was found to be 2.23 nm on the basis of the theory of Förster's energy transfer. Synchronous fluorescence data indicated that interaction of drug with HSA changed the microenvironment around the tryptophan residue. UV–visible spectroscopy and circular dichroism results deciphered the complex formation and conformational alterations in the HSA respectively. Dynamic light scattering was utilized to understand the topology of protein in absence and presence of drug. Thermodynamic parameters obtained from isothermal titration calorimetry (ΔH=−26.01 kJ mol{sup −1} and TΔS=6.5 kJ mol{sup −1}) suggested the involvement of van der Waal interaction and hydrogen bonding. Molecular docking and displacement study with site specific markers suggested that cytosine β-D arabinofuranoside binds to subdomain IB of HSA which is also known as the hemin binding site. This study will be helpful to understand the binding mechanism of cytosine β-D arabinofuranoside with HSA and associated alterations. - Highlights: • Comprehensive insight into the interaction of CBDA with HSA. • The interaction process is spontaneous and exothermic. • The main governing forces for stabilizing HSA–CBDA complex are van der Waal interaction and hydrogen bonding. • CBDA binds at subdomain IB on HSA.

Mechanism of anti-HIV activity of succinylated human serum albumin

NARCIS (Netherlands)

Kuipers, ME; Berg, HVD; Swart, PJ; Laman, Jon; Meijer, DKF; Kopelman, MHGM; Huisman, H

1999-01-01

In the present study, we described the interaction of succinylated human serum albumin (Suc-HSA), a negatively charged anti-HIV-1 active protein, with HIV-1 gp120 and in detail with the third variable domain of gp120 (V3 loop). To this end, different assay formats were tested in which gp120- and

Uptake of heavy metals by Typha capensis from wetland sites polluted by effluent from mineral processing plants: implications of metal-metal interactions.

Science.gov (United States)

Zaranyika, M F; Nyati, W

2017-10-01

The aim of the present work was to demonstrate the existence of metal-metal interactions in plants and their implications for the absorption of toxic elements like Cr. Typha capensis , a good accumulator of heavy metals, was chosen for the study. Levels of Fe, Cr, Ni, Cd, Pb, Cu and Zn were determined in the soil and roots, rhizomes, stems and leaves of T. capensis from three Sites A, B and C polluted by effluent from a chrome ore processing plant, a gold ore processing plant, and a nickel ore processing plant, respectively. The levels of Cr were extremely high at Site A at 5415 and 786-16,047 μg g -1 dry weight in the soil and the plant, respectively, while the levels of Ni were high at Site C at 176 and 24-891 μg g -1 in the soil and the plant, respectively. The levels of Fe were high at all three sites at 2502-7500 and 906-13,833 μg g -1 in the soil and plant, respectively. For the rest of the metals, levels were modest at 8.5-148 and 2-264 μg g -1 in the soil and plant, respectively. Pearson's correlation analysis confirmed mutual synergistic metal-metal interactions in the uptake of Zn, Cu, Co, Ni, Fe, and Cr, which are attributed to the similarity in the radii and coordination geometry of the cations of these elements. The implications of such metal-metal interactions (or effects of one metal on the behaviour of another) on the uptake of Cr, a toxic element, and possible Cr detoxification mechanism within the plant, are discussed.

Transition-metal interactions in aluminum-rich intermetallics

International Nuclear Information System (INIS)

Al-Lehyani, Ibrahim; Widom, Mike; Wang, Yang; Moghadam, Nassrin; Stocks, G. Malcolm; Moriarty, John A.

2001-01-01

The extension of the first-principles generalized pseudopotential theory (GPT) to transition-metal (TM) aluminides produces pair and many-body interactions that allow efficient calculations of total energies. In aluminum-rich systems treated at the pair-potential level, one practical limitation is a transition-metal overbinding that creates an unrealistic TM-TM attraction at short separations in the absence of balancing many-body contributions. Even with this limitation, the GPT pair potentials have been used effectively in total-energy calculations for Al-TM systems with TM atoms at separations greater than 4 Aa. An additional potential term may be added for systems with shorter TM atom separations, formally folding repulsive contributions of the three- and higher-body interactions into the pair potentials, resulting in structure-dependent TM-TM potentials. Towards this end, we have performed numerical ab initio total-energy calculations using the Vienna ab initio simulation package for an Al-Co-Ni compound in a particular quasicrystalline approximant structure. The results allow us to fit a short-ranged, many-body correction of the form a(r 0 /r) b to the GPT pair potentials for Co-Co, Co-Ni, and Ni-Ni interactions

Radiolabeling Of Albumin Particles With Yttrium-90

International Nuclear Information System (INIS)

Nguyen Thi Thu; Nguyen Thi Khanh Giang; Bui Van Cuong, Vo Thi Cam Hoa

2011-01-01

This paper presents the process of the radiolabeling of microaggregated albumin particles with radionuclide Yttrium-90 using the directed method. The albumin microsphere kit was prepared in sodium phosphate buffer. The original solution includes 2 mg albumin particle and 0.5 mg stannous chloride dihydrate. The albumin particles size was ranged from 5 ?m to 30 ?m. The mixture was washed three times with phosphate buffer saline, pH 7.2 by centrifugation and suspended in 0.5 M sodium acetate buffer, pH 6. Yttrium - 90 in 1.0 M acetic acid was collected from 90 Sr/ 90 Y generator. The labeling of the particles with Y-90 (185 MBq) was performed at pH 5.5 in acetate buffer with agitating for 60 min at room temperature. The labeled albumin suspensions were centrifuged at 3000 rpm for 15 min. Labeling yields was calculated using centrifugation, filtration and compared with paper chromatography, which is developed in the Tris Acetic EDTA. In this system, the unbound of Y-90 migrates to an R f of 0.9-1.0 and the radiolabeled albumin particles remains at the point of origin (R f = 0). The size of 90 Y-albumin particles was compared with the albumin particles in the original solution to be sure that they did not change during the labeling treatment. The radiolabeling yields were more than 80%. The labeled compound was dialysis in phosphate buffer. The radiochemical purity was 98%. The 90 Y- albumin is an ideal radiopharmaceutical for potential use in malignant cancer treatment as brachytherapy. (author)

Development of ELISA kit for rat albumin

International Nuclear Information System (INIS)

Yuan Zhigang; Han Shiquan; Liu Yibing; Xu Wenge; Jia Juanjuan

2009-01-01

The Anti-rat albumin serum was prepared by immunized the sheep with rat albumin. A ELISA method was established for rat albumin. The measurement range of the assay was 1-50 mg/L, sensitivity of the assay was 0.42 mg/L, recovery rate was 85.0%-106.0%. Intra-and inter-assay variation coefficients were <8.9% and <12.8% respectively. The correlation coefficients between measured and expected values were 0.999 after serial dilution of the urine samples with high concentrations of rat albumin. A good correlation was observed between the ELISA and RIA methods, and the kit for rat albumin might provide a convenience in exploitation of renal drugs and experimental injury of the kidney. (authors)

The role of albumin conformation in the binding of diazepam to human serum albumin

NARCIS (Netherlands)

Wilting, J.; Hart, B.J. 't; Gier, J.J. de

2006-01-01

The effect of hydrogen, chloride and calcium ions on the binding of diazepare to human serum albumin has been studied by circular dichroism and equilibrium dialysis. In all cases the molar ellipticity of the diazepam-albumin complex increases with pH over the pH range 5 to 9. Under these

Characterizing the interaction between oridonin and bovine serum albumin by a hybrid spectroscopic approach

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhen [Department of Chemistry, Shantou University, Shantou 515063 (China); Chen, Junhui, E-mail: chenjupush@126.com [Interventional Oncology and Minimally Invasive Therapies Department, Peking University Shenzhen Hospital, Shenzhen 518036 (China); Wang, Shaobin [The Fourth People' s Hospital of Shenzhen, Shenzhen 518033 (China); Chen, Zhanguang, E-mail: kqlu@stu.edu.cn [Department of Chemistry, Shantou University, Shantou 515063 (China)

2013-02-15

Oridonin is an effective anticancer drug which has high potency and low systemic toxicity. In this study, the interaction between oridonin and bovine serum albumin (BSA) was investigated by several spectroscopic approaches for the first time. The binding characteristics of oridonin and BSA were determined by fluorescence emission spectra and resonance light scattering spectra. It is showed that the oridonin quenches the fluorescence of BSA and the static quenching constant K{sub SV} is 1.30 Multiplication-Sign 10{sup 4} L mol{sup -1} at 298 K. Moreover, oridonin and BSA form a 1:1 complex with a binding constant of 0.62 Multiplication-Sign 10{sup 4} L mol{sup -1}. On the other hand, the thermodynamic parameters indicate that the binding process was a spontaneous molecular interaction procedure, in which hydrophobic forces played a major role. The structure analysis indicates that oridonin binding results in an increased hydrophobicity around the tryptophan residues of BSA. Additionally, as shown by the UV-vis absorption, synchronous fluorescence and three-dimensional fluorescence results, oridonin could lead to conformational and some microenvironmental changes of BSA. The work provides accurate and full basic data for clarifying the binding mechanism of oridonin with BSA in vitro and is helpful for understanding its effect on protein function during its transportation and distribution in blood. - Highlights: Black-Right-Pointing-Pointer Interaction between oridonin and BSA was evaluated by multi-spectroscopic methods. Black-Right-Pointing-Pointer Binding constant, number of binding sites and thermodynamic parameters were calculated. Black-Right-Pointing-Pointer Oridonin binds to Subdomain II site in BSA and form a 1:1 complex with it. Black-Right-Pointing-Pointer Oridonin-BSA complex is stabilized mainly by hydrophobic force. Black-Right-Pointing-Pointer Oridonin binding induces conformational and microenvironmental changes in BSA.

Spin-rotation interaction of alkali-metal endash He-atom pairs

International Nuclear Information System (INIS)

Walker, T.G.; Thywissen, J.H.; Happer, W.

1997-01-01

A treatment of the spin-rotation coupling between alkali-metal atoms and He atoms is presented. Rotational distortions are accounted for in the wave function using a Coriolis interaction in the rotating frame. The expectation value of the spin-orbit interaction gives values of the spin-rotation coupling that explain previous experimental results. For spin-exchange optical pumping, the results suggest that lighter alkali-metal atoms would be preferred spin-exchange partners, other factors being equal. copyright 1997 The American Physical Society

Defect-impurity interactions in ion-implanted metals

International Nuclear Information System (INIS)

Turos, A.

1986-01-01

An overview of defect-impurity interactions in metals is presented. When point defects become mobile they migrate towards the sinks and on the way can be captured by impurity atoms forming stable associations so-called complexes. In some metallic systems complexes can also be formed athermally during ion implantation by trapping point defects already in the collision cascade. An association of a point defect with an impurity atom leads to its displacement from the lattice site. The structure and stability of complexes are strongly temperature dependent. With increasing temperature they dissociate or grow by multiple defect trapping. The appearance of freely migrating point defects at elevated temperatures, due to ion bombardment or thermal annealing, causes via coupling with defect fluxes, important impurity redistribution. Because of the sensitivity of many metal-in-metal implanted systems to radiation damage the understanding of this processes is essential for a proper interpretation of the lattice occupancy measurements and the optimization of implantation conditions. (author)

Spectroscopic analyses on interaction of bovine serum albumin (BSA) with toluidine blue (TB) and its sonodynamic damage under ultrasonic irradiation

Energy Technology Data Exchange (ETDEWEB)

Wang Jun, E-mail: wangjun890@126.co [Department of Chemistry, Liaoning University, Shenyang 110036 (China); Guo Yuwei [Department of Chemistry, Liaoning University, Shenyang 110036 (China); Department of Chemistry, Baotou Normal College, Baotou 014030 (China); Liu Bin [Department of Pharmacy, Liaoning University, Shenyang 110036 (China); Cheng Chunping [Department of Chemistry, Baotou Normal College, Baotou 014030 (China); Wang Zhiqiu; Han Guangxi; Gao Jingqun; Zhang Xiangdong [Department of Chemistry, Liaoning University, Shenyang 110036 (China)

2011-02-15

In this paper, the toluidine blue (TB) with tricyclic quinone imide plane structure is used as sonosensitizer to study the interaction and sonodynamic damage to bovine serum albumin (BSA) by UV-vis and fluorescence spectroscopy. The results show that the TB can bind to BSA molecules, obviously, and the synergetic effects of TB and ultrasonic irradiation can efficiently damage the BSA molecules. Otherwise, some influencing factors such as ultrasonic irradiation time, TB concentration, pH value and ionic strength on the damage of BSA molecules were also considered by the numbers. Synchronous fluorescence spectroscopy indicates that the tyrosine (Tyr) residues of BSA molecules are damaged more seriously than the tryptophan (Trp) residues under ultrasonic irradiation. - Research Highlights: TB is used as quencher to study interaction to BSA. TB is used as sonosensitizer to study the sonodynamic damage to BSA. Synchronous fluorescence spectroscopy is used to study TB binding site to BSA.

Caffeine and sulfadiazine interact differently with human serum albumin: A combined fluorescence and molecular docking study

Science.gov (United States)

Islam, Mullah Muhaiminul; Sonu, Vikash K.; Gashnga, Pynsakhiat Miki; Moyon, N. Shaemningwar; Mitra, Sivaprasad

2016-01-01

The interaction and binding behavior of the well-known drug sulfadiazine (SDZ) and psychoactive stimulant caffeine (CAF) with human serum albumin (HSA) was monitored by in vitro fluorescence titration and molecular docking calculations under physiological condition. The quenching of protein fluorescence on addition of CAF is due to the formation of protein-drug complex in the ground state; whereas in case of SDZ, the experimental results were explained on the basis of sphere of action model. Although both these compounds bind preferentially in Sudlow's site 1 of the protein, the association constant is approximately two fold higher in case of SDZ (∼4.0 × 104 M-1) in comparison with CAF (∼9.3 × 102 M-1) and correlates well with physico-chemical properties like pKa and lipophilicity of the drugs. Temperature dependent fluorescence study reveals that both SDZ and CAF bind spontaneously with HSA. However, the binding of SDZ with the protein is mainly governed by the hydrophobic forces in contrast with that of CAF; where, the interaction is best explained in terms of electrostatic mechanism. Molecular docking calculation predicts the binding of these drugs in different location of sub-domain IIA in the protein structure.

Combined fluorescence and electrochemical investigation on the binding interaction between organic acid and human serum albumin

Institute of Scientific and Technical Information of China (English)

CHEN Yan-Min; GUO Liang-Hong

2009-01-01

Human serum albumin (HSA) is a plasma protein responsible for the binding and transport of fatty acids and a variety of exogenous chemicals such as drugs and environmental pollutants. Such binding plays a crucial role in determining the ADME (absorption, distribution, metabolism, and excretion) and bioavailability of the pollutants. We report investigation on the binding interaction between HSA and acetic acid (C2), octanoic acid (C8) and dodecanoic acid (C12) by the combination of site-specific fluorescent probe, tryptophan intrinsic fluorescence and tyrosine electrochemistry. Two fluorescent probes, dansylamide and dansyl-L-proline, were employed in the displacement measurement to study fatty acid interaction with the two drug-binding sites on HSA. Intrinsic fluorescence of tryptophan in HSA was monitored upon addition of the fatty acids into HSA. Electrocatalyzed response of the tyrosine residues in HSA by a redox mediator was used to investigate the binding interaction. Qualitatively, observations made by the three approaches are very similar. HSA did not show any change in either fluorescence or electrochemistry after mixing with C2, suggesting there is no significant interaction with the short-chain fatty acid. For C8, the measured signal dropped in a single-exponential fashion, indicative of independent and non-cooperative binding. The calculated association constant and binding ratio is 3.1×106 L/mol and 1 with drug binding Site I, 1.1×107 L/mol and 1 with Site II, and 7.0×104 L/mol and 4 with the tryptophan site. The measurement with C12 displayed multiple phases of fluorescence change, suggesting cooperativity and allosteric effect of C12 binding. These results correlate well with those obtained by the established methods, and validate the new approach as a viable tool to study the interactions of environmental pollutants with biological molecules.

Study on the interaction of tussilagone with human serum albumin (HSA) by spectroscopic and molecular docking techniques

Science.gov (United States)

Xu, Liang; Hu, Yan-Xi; Li, Yan-Cheng; Zhang, Li; Ai, Hai-Xin; Liu, Hong-Sheng; Liu, Yu-Feng; Sang, Yu-Li

2017-12-01

Tussilagone is a sesquiterpenoid which exhibits a variety of pharmacological activities. The interaction of tussilagone with human serum albumin (HSA) was investigated using fluorescence spectroscopy, UV-vis absorption, fluorescence probe experiments, synchronous fluorescence, circular dichroism (CD) spectra, three-dimensional spectra and molecular docking techniques under simulative physiological conditions. The results clarified that the fluorescence quenching of HSA by tussilagone was a static quenching process as a result of HSA-tussilagone (1:1) complex. Tussilagone spontaneously bound to HSA in site I (subdomain IIA), which was primarily driven by hydrophobic forces and hydrogen bonds (ΔH° = -13.89 kJ mol-1, ΔS° = 16.39 J mol-1 K-1). The binding constant was calculated to be 2.182 × 103 L mol-1 and the binding distance was estimated to be 2.07 nm at 291 K, showing the occurrence of fluorescence energy transfer. The results of CD, synchronous and three-dimensional fluorescence spectra all revealed that tussilagone induced the conformational changes of HSA. Meanwhile, the study of molecular docking also indicated that tussilagone could bind to the site I of HSA mainly by hydrophobic and hydrogen bond interactions.

Thyroid albumin originates from blood

NARCIS (Netherlands)

de Vijlder, J. J.; Veenboer, G. J.; van Dijk, J. E.

1992-01-01

Iodoalbumin has been found in the goiter of Dutch goats with a thyroglobulin synthesis defect. Immunohistochemical studies showed that in the goiter the percentage of follicles containing albumin was higher than that in normal thyroid glands. In the albumin-containing follicles of normal and

Enhanced and tunable electric dipole-dipole interactions near a planar metal film

Science.gov (United States)

Zhou, Lei-Ming; Yao, Pei-Jun; Zhao, Nan; Sun, Fang-Wen

2017-08-01

We investigate the enhanced electric dipole-dipole interaction of surface plasmon polaritons (SPPs) supported by a planar metal film waveguide. By taking two nitrogen-vacancy (NV) center electric dipoles in diamond as an example, both the coupling strength and collective relaxation of two dipoles are studied with the numerical Green Function method. Compared to two-dipole coupling on a planar surface, metal film provides stronger and tunable coupling coefficients. Enhancement of the interaction between coupled NV center dipoles could have applications in both quantum information and energy transfer investigation. Our investigation provides systematic results for experimental applications based on a dipole-dipole interaction mediated with SPPs on a planar metal film.

Treatment of Alzheimer disease using combination therapy with plasma exchange and haemapheresis with albumin and intravenous immunoglobulin: Rationale and treatment approach of the AMBAR (Alzheimer Management By Albumin Replacement) study.

Science.gov (United States)

Boada, M; Ramos-Fernández, E; Guivernau, B; Muñoz, F J; Costa, M; Ortiz, A M; Jorquera, J I; Núñez, L; Torres, M; Páez, A

2016-09-01

There is a growing interest in new therapeutic strategies for the treatment of Alzheimer disease (AD) which focus on reducing the beta-amyloid peptide (Aβ) burden in the brain by sequestering plasma Aβ, a large proportion of which is bound to albumin and other proteins. This review discusses the concepts of interaction between Aβ and albumin that have given rise to AMBAR (Alzheimer's Disease Management by Albumin Replacement) project, a new multicentre, randomised, controlled clinical trial for the treatment of AD. Results from preliminary research suggest that Albutein(®) (therapeutic albumin, Grifols) contains no quantifiable levels of Aβ. Studies also show that Albutein(®) has Aβ binding capacity. On the other hand, AD entails a high level of nitro-oxidative stress associated with fibrillar aggregates of Aβ that can induce albumin modification, thus affecting its biological functions. Results from the phase ii study confirm that using therapeutic apheresis to replace endogenous albumin with Albutein(®) 5% is feasible and safe in patients with AD. This process resulted in mobilisation of Aβ and cognitive improvement in treated patients. The AMBAR study will test combination therapy with therapeutic apheresis and haemopheresis with the possible leverage effect of Albutein(®) with intravenous immunoglobulin replacement (Flebogamma(®) DIF). Cognitive, functional, and behavioural changes in patients with mild to moderate AD will be assessed. the AMBAR study represents a new therapeutic perspective for AD. Copyright © 2014 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

Algal-bacterial interactions in metal contaminated floodplain sediments

International Nuclear Information System (INIS)

Boivin, M.E.Y.; Greve, G.D.; Garcia-Meza, J.V.; Massieux, B.; Sprenger, W.; Kraak, M.H.S.; Breure, A.M.; Rutgers, M.; Admiraal, W.

2007-01-01

The aim of the present study was to investigate algal-bacterial interactions in a gradient of metal contaminated natural sediments. By means of multivariate techniques, we related the genetic structure (denaturing gradient gel electrophoresis, DGGE) and the physiological structure (community-level physiological profiling, CLPP) of the bacterial communities to the species composition of the algal communities and to the abiotic environmental variables, including metal contamination. The results revealed that genetic and physiological structure of the bacterial communities correlated with the species composition of the algal community, but hardly to the level of metal pollution. This must be interpreted as an indication for a strong and species-specific linkage of algal and bacterial species in floodplain sediments. Metals were, however, not proven to affect either the algal or the bacterial communities of the Dutch river floodplains. - Algal and bacterial communities in floodplain sediments are interlinked, but are not affected by metal pollution

Investigations on the interactions of aurintricarboxylic acid with bovine serum albumin: Steady state/time resolved spectroscopic and docking studies.

Science.gov (United States)

Bardhan, Munmun; Chowdhury, Joydeep; Ganguly, Tapan

2011-01-10

In this paper, the nature of the interactions between bovine serum albumin (BSA) and aurintricarboxylic acid (ATA) has been investigated by measuring steady state and time-resolved fluorescence, circular dichroism (CD), FT-IR and fluorescence anisotropy in protein environment under physiological conditions. From the analysis of the steady state and time-resolved fluorescence quenching of BSA in aqueous solution in presence of ATA it has been inferred that the nature of the quenching originates from the combined effect of static and dynamic modes. From the determination of the thermodynamic parameters obtained from temperature-dependent changes in K(b) (binding constant) it was apparent that the combined effect of hydrophobic association and electrostatic attraction is responsible for the interaction of ATA with BSA. The effect of ATA on the conformation of BSA has been examined by analyzing CD spectrum. Though the observed results demonstrate some conformational changes in BSA in presence of ATA but the secondary structure of BSA, predominantly of α-helix, is found to retain its identity. Molecular docking of ATA with BSA also indicates that ATA docks through hydrophobic interaction. Copyright © 2010 Elsevier B.V. All rights reserved.

Investigation of binding behaviour of procainamide hydrochloride with human serum albumin using synchronous, 3D fluorescence and circular dichroism

Directory of Open Access Journals (Sweden)

Kirthi Byadagi

2017-04-01

Full Text Available Interaction of procainamide hydrochloride (PAH with human serum albumin (HSA is of great significance in understanding the pharmacokinetic and pharmacodynamic mechanisms of the drug. Multi-spectroscopic techniques were used to investigate the binding mode of PAH to HSA and results revealed the presence of static type of quenching mechanism. The number of binding sites, binding constants and thermodynamic parameters were calculated. The results showed a spontaneous binding of PAH to HSA and hydrophobic interactions played a major role. In addition, the distance between PAH and the Trp–214 was estimated employing the Förster's theory. Site marker competitive experiments indicated that the binding of PAH to HSA primarily took place in subdomain IIA (Sudlow's site I. The influence of interference of some common metal ions on the binding of PAH to HSA was studied. Synchronous fluorescence spectra (SFS, 3D fluorescence spectra and circular dichroism (CD results indicated the conformational changes in the structure of HSA.

Interaction of Avelox with Bovine Serum Albumin and Effect of the Coexistent Drugs on the Reaction

Directory of Open Access Journals (Sweden)

Baosheng Liu

2012-01-01

Full Text Available The interaction between Avelox and bovine serum albumin (BSA was investigated at different temperatures by fluorescence spectroscopy. Results showed that Avelox could quench the intrinsic fluorescence of BSA strongly, and the quenching mechanism was a static quenching process with Förester spectroscopy energy transfer. The electrostatic force played an important role on the conjugation reaction between BSA and Avelox. The order of magnitude of binding constants (Ka was 104, and the number of binding site (n in the binary system was approximately equal to 1. The binding distance (r was less than 3 nm and the primary binding site for Avelox was located in subdomain IIA of BSA. Synchronous fluorescence spectra clearly revealed that the microenvironment of amino acid residues and the conformation of BSA were changed during the binding reaction. In addition, the effect of some antibiotics on the binding constant of Avelox with BSA was also studied.

Composition comprising radioactive labeled-fibrinogen and albumin

International Nuclear Information System (INIS)

Charlton, J.C.; Gravett, D.L.

1976-01-01

The stability of fibrinogen is improved by mixing it with albumin, preferably at least 5 parts by weight of albumin per part by weight of fibrinogen. By this invention, iodinated ( 125 I) human fibrinogen can be stabilized with human serum albumin for use in the diagnosis of thrombi

Albumin extravasation in bicuculline-induced blood-brain barrier dysfunction

International Nuclear Information System (INIS)

Persson, L.I.; Rosengren, L.E.; Johansson, B.B.

1980-01-01

The extravasation of endogeneous rat albumin and exogeneous 125 I-labeled human serum albumin was compared in rats subjected to bicuculline-induced blood-brain barrier dysfunction. The correlation between rocket immunoelectrophoretic assays of endogeneous rat albumin and 125 I-labeled human serum albumin, assayed by gamma scintillation counting, was good irrespective of whether 125 I-labeled albumin was studied in whole brain tissue or in brain homogenates. The ratio of brain to serum albumin was similar with the two assay methods. (author)

Preparation of Tc-99m-macroaggregated albumin from recombinant human albumin for lung perfusion imaging.

Science.gov (United States)

Hunt, A P; Frier, M; Johnson, R A; Berezenko, S; Perkins, A C

2006-01-01

Human serum albumin (HSA) extracted from pooled blood taken from human donors is used in the production of (99m)Tc-labelled macroaggregated albumin (MAA) for lung perfusion imaging. However, concerns for the safety of blood-derived products due to potential contamination by infective agents (e.g. new variant CJD), make alternative production methods necessary. Recombinant DNA technology is a promising method of albumin production avoiding problems associated with human-derived HSA. This paper presents results comparing MAA prepared from recombinant human albumin (rHA, Recombumin) (rMAA) with in-house produced HSA MAA (hMAA) and commercially available MAA (cMAA). (99m)Tc-MAA was prepared using previously published production methods by heating a mixture of albumin and stannous chloride in acetate buffer (pH 5.4) at 70 degrees C for 20 min. Parameters investigated include aggregate size, radiolabelling efficiency, radiochemical and aggregate stability at 4 degrees C and in vitro (in whole human blood) at 37 degrees C and biodistribution studies. Results showed that rMAA could be produced with similar morphology, labelling efficiency and stability to hMAA and cMAA. Our findings confirm that rHA shows significant potential as a direct replacement for HSA in commercially available MAA.

SPECTROPHOTOMETRIC ANALYSIS OF BOVINE SERUM ALBUMIN IN PRESENCE OF 1-(4-METHYLPHENYL)-3-PHENYLPROP-2-EN-1-ONES

OpenAIRE

S. Garg; N. Raghav

2013-01-01

A series of chalcones was synthesized by the Claisen-Schmidt condensation and the structures of 1- (4-methylphenyl)-3-phenylprop-2-en-1-ones were established with the help of IR and NMR study, then their effect was observed on bovine serum albumin. We have found that the synthesized chalcones interacted with bovine serum albumin and produce a great effect on their presence.

Comparative Studies on the Interaction of Cochinchinenin A and Loureirin B with Bovine Serum Albumin

Directory of Open Access Journals (Sweden)

Tianming Yang

2013-01-01

Full Text Available This paper describes the simple, sensitive, and effective spectrophotometric methods based on ultraviolet, fluorescence and circular dichroism for revealing the interactional mechanism of Cochinchinenin A (CA and Loureirin B (LB with bovine serum albumin (BSA. Under simulated physiological conditions, it was demonstrated that the fluorescence quenching mechanisms between CA (or LB and BSA as a static quenching mode, or a combined quenching (dynamic and static quenching mode were related to concentration level of CA (or LB. The binding distance (rCA, rLB and the quenching efficiency (KSV, especially for the binding constants value of ligands to BSA, were affected by the methoxyl group at position 4 at different temperatures. The corresponding thermodynamic parameters were also obtained and indicated that electrostatic forces play a major role in the formation of the LB-BSA complex, but probably a combined force for CA-BSA complex. Furthermore, synchronous fluorescence spectroscopy and circular dichroism spectra demonstrated that the secondary structures of BSA were changed to varying degrees by the binding of CA (or LB.

Thermodynamics of the interaction of the food additive tartrazine with serum albumins: a microcalorimetric investigation.

Science.gov (United States)

Basu, Anirban; Kumar, Gopinatha Suresh

2015-05-15

The thermodynamics of the interaction of the food colourant tartrazine with two homologous serum proteins, HSA and BSA, were investigated, employing microcalorimetric techniques. At T=298.15K the equilibrium constants for the tartrazine-BSA and HSA complexation process were evaluated to be (1.92 ± 0.05) × 10(5)M(-1) and (1.04 ± 0.05) × 10(5)M(-1), respectively. The binding was driven by a large negative standard molar enthalpic contribution. The binding was dominated essentially by non-polyelectrolytic forces which remained largely invariant at all salt concentrations. The polyelectrolytic contribution was weak at all salt concentrations and accounted for only 6-18% of the total standard molar Gibbs energy change in the salt concentration range 10-50mM. The negative standard molar heat capacity values, in conjunction with the enthalpy-entropy compensation phenomenon observed, established the involvement of dominant hydrophobic forces in the complexation process. Tartrazine enhanced the stability of both serum albumins against thermal denaturation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Medium-chain fatty acid binding to albumin and transfer to phospholipid bilayers

International Nuclear Information System (INIS)

Hamilton, J.A.

1989-01-01

Temperature-dependent (5-42 degree C) 13 C NMR spectra of albumin complexes with 90% isotopically substituted [1- 13 C]octanoic or [1- 13 C]decanoic acids showed a single peak at >30 degree C but three peaks at lower temperatures. The chemical-shift differences result from different ionic and/or hydrogen-bonding interactions between amino acid side chains and the fatty acid carboxyl carbon. Rapid exchange of fatty acid among binding sites obscures these sites at temperatures >30 degree C. Rate constants for exchange at 33 degree C were 350 sec -1 for octanoate and 20 sec -1 for decanoate. Temperature-dependent data for octanoate showed an activation energy of 2 kcal/mol for exchange. Spectra of albumin complexes with the 12-carbon saturated fatty acid, lauric acid, had several narrow laurate carboxyl peaks at 35 degree C, indicating longer lifetimes in the different binding sites. Fatty acid exchange between albumin and model membranes (phosphatidylcholine bilayers) occurred on a time scale comparable to that for exchange among albumin binding sites, following the order octanoate > decanoate > laurate. The equilibrium distribution of fatty acid between lipid bilayers and protein was measured directly from NMR spectra. Decreasing pH increased the relative affinity of fatty acid for the lipid bilayer. The results predict that the relative affinity of octanoic acid for albumin and membranes will be similar to that of long-chain fatty acids, but the rate of equilibration will be ∼ 10 4 faster for octanoic acid

Van der Waals interaction between metal and atom

International Nuclear Information System (INIS)

Rao, P.R.; Mukhopadhyay, G.

1984-07-01

A dielectric response approach to the Van der Waals interaction between an atom and a planar metal surface is presented. An exact formula in terms of a form factor is derived within the point dipole approximation and non-retarded limit valid for shorter separation. The interaction potential is studied via SCIB model, and a substantial modification over its classical form is found at shorter distances. (author)

Dynamic interactions of Leidenfrost droplets on liquid metal surface

Science.gov (United States)

Ding, Yujie; Liu, Jing

2016-09-01

Leidenfrost dynamic interaction effects of the isopentane droplets on the surface of heated liquid metal were disclosed. Unlike conventional rigid metal, such conductive and deformable liquid metal surface enables the levitating droplets to demonstrate rather abundant and complex dynamics. The Leidenfrost droplets at different diameters present diverse morphologies and behaviors like rotation and oscillation. Depending on the distance between the evaporating droplets, they attract and repulse each other through the curved surfaces beneath them and their vapor flows. With high boiling point up to 2000 °C, liquid metal offers a unique platform for testing the evaporating properties of a wide variety of liquid even solid.

Biophysical study on the interaction between two palladium(II) complexes and human serum albumin by Multispectroscopic methods

Energy Technology Data Exchange (ETDEWEB)

Saeidifar, Maryam, E-mail: saeidifar@merc.ac.ir [Department of Nanotechnology and Advanced Materials, Materials and Energy Research Center, Karaj (Iran, Islamic Republic of); Mansouri-Torshizi, Hassan [Department of Chemistry, University of Sistan and Baluchestan, Zahedan (Iran, Islamic Republic of); Akbar Saboury, Ali [Institute of Biochemistry and Biophysics, University of Tehran, Tehran (Iran, Islamic Republic of)

2015-11-15

The interaction of [Pd(bpy)(n-pr-dtc)]Br (I) and ([Pd(phen)(n-pr-dtc)]Br (II) (bpy=2,2′-bipyridine, phen=1,10-phenanthroline and n-pr-dtc=n-propyldithiocarbamate) with human serum albumin (HSA) was investigated using fluorescence, UV–vis absorption and circular dichroism (CD) spectroscopy techniques under simulative physiological conditions (pH=7.4). It was observed that the two complexes interact with HSA via static fluorescence quenching. The thermodynamic parameters indicate that the binding process was spontaneous and that hydrogen bonds and van der Waals forces play a major role in the association of the HSA–Pd(II) complexes. The activation energy (E{sub a}), binding constant (K{sub b}) and number of binding sites (n) of the HSA–Pd(II) complexes were calculated from fluorescence data at 293 K, 303 K and 311 K. The conformational alternations of protein secondary structure in the presence of Pd(II) complexes were demonstrated using synchronous fluorescence, three-dimensional fluorescence spectra, UV–vis absorption and circular dichroism techniques. Furthermore, the apparent distance between donor (HSA) and acceptor (Pd(II) complexes) was determined using fluorescence resonance energy transfer (FRET). The binding studies between these complexes and HSA give us key insights into the transportation, distribution and toxicity of newly design antitumor Pd(II) complexes in human blood. - Highlights: • The HSA binding properties of two Palladium (II) complexes were studied. • Static quenching mechanism is effective in the interaction of HSA with Pd(II) complexes. • Hydrogen bonds and van der Waals forces were involved in the Pd(II) complexes–HSA interaction. • 3D fluorescence was used to study the interaction between two complexes and HSA.

Multi-spectroscopic studies on the interaction of human serum albumin with astilbin: Binding characteristics and structural analysis

Energy Technology Data Exchange (ETDEWEB)

Wang, Jin; Li, Shuang; Peng, Xialian; Yu, Qing [Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, Department Chemistry and Chemical Engineering, Guangxi Normal University, Ministry of Education of China, Guilin 541004 (China); Bian, Hedong, E-mail: gxnuchem312@yahoo.com.cn [Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, Department Chemistry and Chemical Engineering, Guangxi Normal University, Ministry of Education of China, Guilin 541004 (China); Huang, Fuping [Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, Department Chemistry and Chemical Engineering, Guangxi Normal University, Ministry of Education of China, Guilin 541004 (China); Liang, Hong, E-mail: lianghongby@yahoo.com.cn [Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, Department Chemistry and Chemical Engineering, Guangxi Normal University, Ministry of Education of China, Guilin 541004 (China)

2013-04-15

Five spectroscopic techniques were used to investigate the interaction of astilbin (ASN) with human serum albumin (HSA). UV–vis absorption measurements prove that ASN–HSA complex can be formed. The analysis of fluorescence spectra reveal that in the presence of ASN, quenching mechanism of HSA is considered as static quenching. The quenching rate constant k{sub q}, K{sub SV} and the binding constant K were estimated. According to the van't Hoff equation, the thermodynamic parameters enthalpy change (ΔΗ) and entropy change (ΔS) were calculated to be −12.94 kJ mol{sup −1} and 35.92 J mol{sup −1} K{sup −1}, respectively. These indicate that the hydrophobic interaction is the major forces between ASN and HSA, but the hydrogen bond interaction cannot be excluded. The changes in the secondary structure of HSA which was induced by ASN were determined by circular dichroism (CD), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. -- Graphical abstract: In this paper, the interaction of HSA with ASN was systematically studied under simulated physiological conditions by using UV–vis absorption, CD, FT-IR, fluorescence and Raman spectroscopic approaches. The quenching constant k{sub q}, K{sub SV} and the binding constant K were estimated. The changes in the secondary structure of HSA were studied by Circular dichroism (CD), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The UV–visible absorption spectra of HSA in the absence and presence of different concentration of ASN (1) and fluorescence spectra of HSA in the absence and the presence of ASN (2). Highlights: ► Interaction of ASN and HSA has been studied by five spectroscopic techniques. ► Hydrophobic interaction is the major forces between ASN and HSA. ► Binding of ASN induced the changes in the secondary structure of HSA.

A tripartite approach identifies the major sunflower seed albumins.

Science.gov (United States)

Jayasena, Achala S; Franke, Bastian; Rosengren, Johan; Mylne, Joshua S

2016-03-01

We have used a combination of genomic, transcriptomic, and proteomic approaches to identify the napin-type albumin genes in sunflower and define their contributions to the seed albumin pool. Seed protein content is determined by the expression of what are typically large gene families. A major class of seed storage proteins is the napin-type, water soluble albumins. In this work we provide a comprehensive analysis of the napin-type albumin content of the common sunflower (Helianthus annuus) by analyzing a draft genome, a transcriptome and performing a proteomic analysis of the seed albumin fraction. We show that although sunflower contains at least 26 genes for napin-type albumins, only 15 of these are present at the mRNA level. We found protein evidence for 11 of these but the albumin content of mature seeds is dominated by the encoded products of just three genes. So despite high genetic redundancy for albumins, only a small sub-set of this gene family contributes to total seed albumin content. The three genes identified as producing the majority of sunflower seed albumin are potential future candidates for manipulation through genetics and breeding.

From guest to ligand - A study on the competing interactions of antitumor drug resveratrol with β-cyclodextrin and bovine serum albumin

International Nuclear Information System (INIS)

Li, Xudong; Li, Hui; Liu, Min; Li, Guangqian; Li, Linwei; Sun, Dezhi

2011-01-01

Graphical abstract: Thermodynamic behavior of the interaction between bovine serum albumin and antitumor drug resveratrol delivered by β-cyclodextrin in buffer solutions (pH 7.40) have been investigated by ITC combined with UV, FS and circular dichroism at 298.15 K. The results indicated that the affinity of resveratrol with the host (β-cyclodextrin) was evidently weaker than that of the drug with the both classes of binding sites on the protein molecule. Highlights: → Supramolecular complex of a drug with BSA could form in aqueous medium. → A set of thermodynamic parameters were determined. → Affinity of the drug to β-CD is weaker than that of it to the protein. → The molecular conformation of BSA was (slightly) changed by the drug. - Abstract: Interaction between bovine serum albumin (BSA) and resveratrol (RES) included by β-cyclodextrin (β-CD) in Tris-HCl aqueous buffer solutions (pH 7.4) has been investigated by isothermal titration calorimetry (ITC) combined with ultraviolet, fluorescence and circular dichroism spectra analyses. The results indicate that there are two classes of ligand binding sites. The first class of binding is mainly driven by enthalpy, while the second one is driven by both enthalpy and entropy. The secondary structure of BSA in the aqueous system was slightly changed with addition of the drug. Thermodynamic parameters, i.e., equilibrium constants, standard enthalpy changes and the entropy effects for the binding process of RES with BSA were calculated based on the calorimetric data. In fact, due to the poor solubility of RES in aqueous buffer medium, these parameters could not be determined by the employed experimental method without the existence of the CD.

From guest to ligand - A study on the competing interactions of antitumor drug resveratrol with {beta}-cyclodextrin and bovine serum albumin

Energy Technology Data Exchange (ETDEWEB)

Li, Xudong [College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, Shandong Province 252059 (China); Department of Clinical Laboratory, Liaocheng People' s Hospital, Liaocheng, Shandong Province 252000 (China); Li, Hui [College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, Shandong Province 252059 (China); Liu, Min, E-mail: liumin_panpan@163.com [College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, Shandong Province 252059 (China); Li, Guangqian; Li, Linwei [College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, Shandong Province 252059 (China); Sun, Dezhi, E-mail: sundezhisdz@163.com [College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, Shandong Province 252059 (China)

2011-07-10

Graphical abstract: Thermodynamic behavior of the interaction between bovine serum albumin and antitumor drug resveratrol delivered by {beta}-cyclodextrin in buffer solutions (pH 7.40) have been investigated by ITC combined with UV, FS and circular dichroism at 298.15 K. The results indicated that the affinity of resveratrol with the host ({beta}-cyclodextrin) was evidently weaker than that of the drug with the both classes of binding sites on the protein molecule. Highlights: {yields} Supramolecular complex of a drug with BSA could form in aqueous medium. {yields} A set of thermodynamic parameters were determined. {yields} Affinity of the drug to {beta}-CD is weaker than that of it to the protein. {yields} The molecular conformation of BSA was (slightly) changed by the drug. - Abstract: Interaction between bovine serum albumin (BSA) and resveratrol (RES) included by {beta}-cyclodextrin ({beta}-CD) in Tris-HCl aqueous buffer solutions (pH 7.4) has been investigated by isothermal titration calorimetry (ITC) combined with ultraviolet, fluorescence and circular dichroism spectra analyses. The results indicate that there are two classes of ligand binding sites. The first class of binding is mainly driven by enthalpy, while the second one is driven by both enthalpy and entropy. The secondary structure of BSA in the aqueous system was slightly changed with addition of the drug. Thermodynamic parameters, i.e., equilibrium constants, standard enthalpy changes and the entropy effects for the binding process of RES with BSA were calculated based on the calorimetric data. In fact, due to the poor solubility of RES in aqueous buffer medium, these parameters could not be determined by the employed experimental method without the existence of the CD.

Some Case Studies on Metal-Microbe Interactions to Remediate Heavy Metals- Contaminated Soils in Korea

Science.gov (United States)

Chon, Hyo-Taek

2015-04-01

Conventional physicochemical technologies to remediate heavy metals-contaminated soil have many problems such as low efficiency, high cost and occurrence of byproducts. Recently bioremediation technology is getting more and more attention. Bioremediation is defined as the use of biological methods to remediate and/or restore the contaminated land. The objectives of bioremediation are to degrade hazardous organic contaminants and to convert hazardous inorganic contaminants to less toxic compounds of safe levels. The use of bioremediation in the treatment of heavy metals in soils is a relatively new concept. Bioremediation using microbes has been developed to remove toxic heavy metals from contaminated soils in laboratory scale to the contaminated field sites. Recently the application of cost-effective and environment-friendly bioremediation technology to the heavy metals-contaminated sites has been gradually realized in Korea. The merits of bioremediation include low cost, natural process, minimal exposure to the contaminants, and minimum amount of equipment. The limitations of bioremediation are length of remediation, long monitoring time, and, sometimes, toxicity of byproducts for especially organic contaminants. From now on, it is necessary to prove applicability of the technologies to contaminated sites and to establish highly effective, low-cost and easy bioremediation technology. Four categories of metal-microbe interactions are generally biosorption, bioreduction, biomineralization and bioleaching. In this paper, some case studies of the above metal-microbe interactions in author's lab which were published recently in domestic and international journals will be introduced and summarized.

Proximal Tubules Have the Capacity to Regulate Uptake of Albumin.

Science.gov (United States)

Wagner, Mark C; Campos-Bilderback, Silvia B; Chowdhury, Mahboob; Flores, Brittany; Lai, Xianyin; Myslinski, Jered; Pandit, Sweekar; Sandoval, Ruben M; Wean, Sarah E; Wei, Yuan; Satlin, Lisa M; Wiggins, Roger C; Witzmann, Frank A; Molitoris, Bruce A

2016-02-01

Evidence from multiple studies supports the concept that both glomerular filtration and proximal tubule (PT) reclamation affect urinary albumin excretion rate. To better understand these roles of glomerular filtration and PT uptake, we investigated these processes in two distinct animal models. In a rat model of acute exogenous albumin overload, we quantified glomerular sieving coefficients (GSC) and PT uptake of Texas Red-labeled rat serum albumin using two-photon intravital microscopy. No change in GSC was observed, but a significant decrease in PT albumin uptake was quantified. In a second model, loss of endogenous albumin was induced in rats by podocyte-specific transgenic expression of diphtheria toxin receptor. In these albumin-deficient rats, exposure to diphtheria toxin induced an increase in albumin GSC and albumin filtration, resulting in increased exposure of the PTs to endogenous albumin. In this case, PT albumin reabsorption was markedly increased. Analysis of known albumin receptors and assessment of cortical protein expression in the albumin overload model, conducted to identify potential proteins and pathways affected by acute protein overload, revealed changes in the expression levels of calreticulin, disabled homolog 2, NRF2, angiopoietin-2, and proteins involved in ATP synthesis. Taken together, these results suggest that a regulated PT cell albumin uptake system can respond rapidly to different physiologic conditions to minimize alterations in serum albumin level. Copyright © 2016 by the American Society of Nephrology.

Spectroscopic analyses on interaction of bovine serum albumin (BSA) with toluidine blue (TB) and its sonodynamic damage under ultrasonic irradiation

International Nuclear Information System (INIS)

Wang Jun; Guo Yuwei; Liu Bin; Cheng Chunping; Wang Zhiqiu; Han Guangxi; Gao Jingqun; Zhang Xiangdong

2011-01-01

In this paper, the toluidine blue (TB) with tricyclic quinone imide plane structure is used as sonosensitizer to study the interaction and sonodynamic damage to bovine serum albumin (BSA) by UV-vis and fluorescence spectroscopy. The results show that the TB can bind to BSA molecules, obviously, and the synergetic effects of TB and ultrasonic irradiation can efficiently damage the BSA molecules. Otherwise, some influencing factors such as ultrasonic irradiation time, TB concentration, pH value and ionic strength on the damage of BSA molecules were also considered by the numbers. Synchronous fluorescence spectroscopy indicates that the tyrosine (Tyr) residues of BSA molecules are damaged more seriously than the tryptophan (Trp) residues under ultrasonic irradiation. - Research Highlights: → TB is used as quencher to study interaction to BSA. → TB is used as sonosensitizer to study the sonodynamic damage to BSA. → Synchronous fluorescence spectroscopy is used to study TB binding site to BSA.

High-power laser-metal interactions in pressurized gaseous atmospheres

Energy Technology Data Exchange (ETDEWEB)

Bitelli, G. [ENEA, Centro Ricerche Frascati, Rome (Italy). Dip. Innovazione; Lugomer, S.; Furic, K.; Ivanda, M. [Ruder Boskovic Institute, Zagreb (Croatia); Stipancic, M. [Electrotechnical faculty, Osijek (Croatia); Stubicar, M. [Faculty of natural sciences and mathematics, Zagreb (Croatia); Gamulin, O. [School of medicine, Univ. of Zagreb, Zagreb (Croatia)

1996-09-01

Metal surfaces were irradiated in pressurized gaseous atmospheres by a CO{sub 2} laser beam. The gaseous pressures ranged from 2 atm to 6 atm, the energy density of the light beam was about 20-50 J/cm{sup 2} with a power density {approx} 10{sup 9} W/cm{sup 2} and a pulse duration p 150 ns. In the above conditions some new effects were observed. The laser-material interaction occurred in a highly absorptive plasma regime, meaning that the metal surface was effectively screened from the beam. The interaction ended either with plasma adiabatic expansion, in the case of Mo (in O{sub 2}), Te (in N{sub 2}) and T{sub i} (in N{sub 2}), or with plasma explosion, in the case of T{sub i} (in O{sub 2}). The metal surface properties were studied by means of optical analysis, microhardness tests, X-ray diffraction and Raman backscattering.

DETERMINATION OF SERUM ALBUMIN WITH ...

African Journals Online (AJOL)

The reaction of tribromoarsenazo(TB-ASA) with serum albumin in the presence of emulgent OP was studied by spectrophotometry. In a Britton-Robinson buffer solution at pH 2.9, tribromoarsenazo and bovine serum albumin can immediately form a red compound in the presence of emulgent OP with a maximum absorption ...

Metal supplementation to UASB bioreactors: from cell-metal interactions to full-scale application

International Nuclear Information System (INIS)

Fermoso, Fernando G.; Bartacek, Jan; Jansen, Stefan; Lens, Piet N.L.

2009-01-01

Upflow anaerobic sludge bed (UASB) bioreactors are commonly used for anaerobic wastewater treatment. Trace metals need to be dosed to these bioreactors to maintain microbial metabolism and growth. The dosing needs to balance the supply of a minimum amount of micronutrients to support a desired microbial activity or growth rate with a maximum level of micronutrient supply above which the trace metals become inhibitory or toxic. In studies on granular sludge reactors, the required micronutrients are undefined and different metal formulations with differences in composition, concentration and species are used. Moreover, an appropriate quantification of the required nutrient dosing and suitable ranges during the entire operational period has been given little attention. This review summarizes the state-of-the-art knowledge of the interactions between trace metals and cells growing in anaerobic granules, which is the main type of biomass retention in anaerobic wastewater treatment reactors. The impact of trace metal limitation as well as overdosing (toxicity) on the biomass is overviewed and the consequences for reactor performance are detailed. Special attention is given to the influence of metal speciation in the liquid and solid phase on bioavailability. The currently used methods for trace metal dosing into wastewater treatment reactors are overviewed and ways of optimization are suggested.

Metal supplementation to UASB bioreactors: from cell-metal interactions to full-scale application

Energy Technology Data Exchange (ETDEWEB)

Fermoso, Fernando G. [Sub-department of Environmental Technology, Wageningen University, ' Biotechnion' -Bomenweg 2, P.O. Box 8129, 6700 EV Wageningen (Netherlands); Bartacek, Jan [Sub-department of Environmental Technology, Wageningen University, ' Biotechnion' -Bomenweg 2, P.O. Box 8129, 6700 EV Wageningen (Netherlands); Pollution Prevention and Control core, UNESCO-IHE, P.O. Box 3015, 2601 DA Delft (Netherlands); Jansen, Stefan [Laboratory of Physical Chemistry and Colloid Science, Wageningen University, Dreijenplein 6, 6703 HB Wageningen (Netherlands); Lens, Piet N.L., E-mail: Piet.Lens@wur.nl [Sub-department of Environmental Technology, Wageningen University, ' Biotechnion' -Bomenweg 2, P.O. Box 8129, 6700 EV Wageningen (Netherlands); Pollution Prevention and Control core, UNESCO-IHE, P.O. Box 3015, 2601 DA Delft (Netherlands)

2009-06-01

Upflow anaerobic sludge bed (UASB) bioreactors are commonly used for anaerobic wastewater treatment. Trace metals need to be dosed to these bioreactors to maintain microbial metabolism and growth. The dosing needs to balance the supply of a minimum amount of micronutrients to support a desired microbial activity or growth rate with a maximum level of micronutrient supply above which the trace metals become inhibitory or toxic. In studies on granular sludge reactors, the required micronutrients are undefined and different metal formulations with differences in composition, concentration and species are used. Moreover, an appropriate quantification of the required nutrient dosing and suitable ranges during the entire operational period has been given little attention. This review summarizes the state-of-the-art knowledge of the interactions between trace metals and cells growing in anaerobic granules, which is the main type of biomass retention in anaerobic wastewater treatment reactors. The impact of trace metal limitation as well as overdosing (toxicity) on the biomass is overviewed and the consequences for reactor performance are detailed. Special attention is given to the influence of metal speciation in the liquid and solid phase on bioavailability. The currently used methods for trace metal dosing into wastewater treatment reactors are overviewed and ways of optimization are suggested.

Study on the interaction of a copper(II) complex containing the artificial sweetener aspartame with human serum albumin.

Science.gov (United States)

Shahabadi, Nahid; Khodaei, Mohammad Mehdi; Kashanian, Soheila; Kheirdoosh, Fahimeh; Filli, Soraya Moradi

2014-05-01

A copper(II) complex containing aspartame (APM) as ligand, Cu(APM)2Cl2·2H2O, was synthesized and characterized. In vitro binding interaction of this complex with human serum albumin (HSA) was studied at physiological pH. Binding studies of this complex with HSA are useful for understanding the Cu(APM)2Cl2·2H2O-HSA interaction mechanism and providing guidance for the application and design of new and more efficient artificial sweeteners drive. The interaction was investigated by spectrophotometric, spectrofluorometric, competition experiment and circular dichroism. Hyperchromicity observed in UV absorption band of Cu(APM)2Cl2·2H2O. A strong fluorescence quenching reaction of HSA to Cu(APM)2Cl2·2H2O was observed and the binding constant (Kf) and corresponding numbers of binding sites (n) were calculated at different temperatures. Thermodynamic parameters, enthalpy change (∆H) and entropy change (∆S) were calculated to be -458.67 kJ mol(-1) and -1,339 J mol(-1 )K(-1) respectively. According to the van't Hoff equation, the reaction is predominantly enthalpically driven. In conformity with experimental results, we suggest that Cu(APM)2Cl2·2H2O interacts with HSA. In comparison with previous study, it is found that the Cu(II) complex binds stronger than aspartame.

Preparation and characterization of microspheres of albumin-heparin conjugates

NARCIS (Netherlands)

Kwon, Glen S.; Bae, You Han; Kim, Sung Wan; Cremers, Harry; Cremers, H.F.M.; Feijen, Jan

1991-01-01

Albumin-heparin microspheres have been prepared as a new drug carrier. A soluble albumin-heparin conjugate was synthesized by forming amide bonds between human serum albumin and heparin. After purification the albumin-heparin conjugate was crosslinked in a water-in-oil emulsion to form

Fibrinogen adsorption on blocked surface of albumin

DEFF Research Database (Denmark)

Holmberg, Maria; Hou, Xiaolin

2011-01-01

We have investigated the adsorption of albumin and fibrinogen onto PET (polyethylene terephthalate) and glass surfaces and how pre-adsorption of albumin onto these surfaces can affect the adsorption of later added fibrinogen. For materials and devices being exposed to blood, adsorption...... of fibrinogen is often a non-wanted event, since fibrinogen is part of the clotting cascade and unspecific adsorption of fibrinogen can have an influence on the activation of platelets. Albumin is often used as blocking agent for avoiding unspecific protein adsorption onto surfaces in devices designed to handle...... energies, the adsorption of both albumin and fibrinogen has been monitored simultaneously on the same sample. Information about topography and coverage of adsorbed protein layers has been obtained using AFM (Atomic Force Microscopy) analysis in liquid. Our studies show that albumin adsorbs in a multilayer...

Interaction of an antiepileptic drug, lamotrigine with human serum albumin (HSA): Application of spectroscopic techniques and molecular modeling methods.

Science.gov (United States)

Poureshghi, Fatemeh; Ghandforoushan, Parisa; Safarnejad, Azam; Soltani, Somaieh

2017-01-01

Lamotrigine (an epileptic drug) interaction with human serum albumin (HSA) was investigated by fluorescence, UV-Vis, FTIR, CD spectroscopic techniques, and molecular modeling methods. Binding constant (K b ) of 5.74×10 3 and number of binding site of 0.97 showed that there is a slight interaction between lamotrigine and HSA. Thermodynamic studies was constructed using the flourimetric titrations in three different temperatures and the resulted data used to calculate the parameters using Vant Hoff equation. Decreased Stern Volmer quenching constant by enhanced temperature revealed the static quenching mechanism. Negative standard enthalpy (ΔH) and standard entropy (ΔS) changes indicated that van der Waals interactions and hydrogen bonds were dominant forces which facilitate the binding of Lamotrigine to HSA, the results were confirmed by molecular docking studies which showed no hydrogen binding. The FRET studies showed that there is a possibility of energy transfer between Trp214 and lamotrigine. Also the binding of lamotrigine to HSA in the studied concentrations was not as much as many other drugs, but the secondary structure of the HSA was significantly changed following the interaction in a way that α-helix percentage was reduced from 67% to 57% after the addition of lamotrigine in the molar ratio of 4:1 to HSA. According to the docking studies, lamotrigine binds to IB site preferably. Copyright © 2016. Published by Elsevier B.V.

The interaction of 2-mercaptobenzimidazole with human serum albumin as determined by spectroscopy, atomic force microscopy and molecular modeling.

Science.gov (United States)

Li, Yuqin; Jia, Baoxiu; Wang, Hao; Li, Nana; Chen, Gaopan; Lin, Yuejuan; Gao, Wenhua

2013-04-01

The interaction of 2-mercaptobenzimidazole (MBI) with human serum albumin (HSA) was studied in vitro by equilibrium dialysis under normal physiological conditions. This study used fluorescence, ultraviolet-visible spectroscopy (UV-vis), Fourier transform infrared (FT-IR), circular dichroism (CD) and Raman spectroscopy, atomic force microscopy (AFM) and molecular modeling techniques. Association constants, the number of binding sites and basic thermodynamic parameters were used to investigate the quenching mechanism. Based on the fluorescence resonance energy transfer, the distance between the HSA and MBI was 2.495 nm. The ΔG(0), ΔH(0), and ΔS(0) values across temperature indicated that the hydrophobic interaction was the predominant binding Force. The UV, FT-IR, CD and Raman spectra confirmed that the HSA secondary structure was altered in the presence of MBI. In addition, the molecular modeling showed that the MBI-HSA complex was stabilized by hydrophobic forces, which resulted from amino acid residues. The AFM results revealed that the individual HSA molecule dimensions were larger after interaction with MBI. Overall, this study suggested a method for characterizing the weak intermolecular interaction. In addition, this method is potentially useful for elucidating the toxigenicity of MBI when it is combined with the biomolecular function effect, transmembrane transport, toxicological testing and other experiments. Copyright © 2012 Elsevier B.V. All rights reserved.

A Spectroscopic Approach to Investigate the Molecular Interactions between the Newly Approved Irreversible ErbB blocker "Afatinib" and Bovine Serum Albumin.

Directory of Open Access Journals (Sweden)

Amer M Alanazi

Full Text Available The interaction of afatinib (AFB with bovine serum albumin (BSA was examined via fluorescence and UV-Vis spectroscopy. Spectrofluorimetric measurements revealed that AFB can strongly quench the BSA intrinsic fluorescence through producing a non-fluorescent complex. This quenching mechanism was thoroughly investigated with regard to the type of quenching, binding constant, number of binding locations and the fundamental thermodynamic parameters. Subsequently, the association constant of AFB with BSA was computed at three different temperatures and was found to range from 7.34 to 13.19 x10(5 L mol(-1. Thermodynamic parameters calculations demonstrated a positive ΔSƟ value with both negative ΔHϴ and ΔGϴ values for AFB-BSA complex, which in turn infers that a spontaneous binding is taking place with both electrostatic bonding and hydrophobic interactions participating in the binding of AFB and BSA. Similarly, the UV absorption spectra of AFB-BSA system were studied and confirmed the interaction. Conformational alteration of the protein upon binding to AFB was elaborated with the aid of three dimensional fluorescence measurements as well as synchronous fluorescence spectra.

The development of radioimmunoassay kit for rat albumin

International Nuclear Information System (INIS)

Yuan Zhigang; Han Shiquan; Liu Yibing; Xu Wenge

2006-01-01

The Anti-rat albumin serum is prepared by immunized the sheep with rat albumin. A radioimmunoassay method is established for rat albumin. The measurement range of the assay is 1-50 mg/L, sensitivity of the assay is 0.12 mg/L, recovery rate is 97.8%- 108.4%. Intra- and inter-assay variation coefficients are <4.0% and <8.2% respectively. The correlation coefficients between measured and expected values are more than 0.990 after serial dilution of the urine samples with high concentrations of rat albumin. The kit for rat albumin might provide a convenience in exploitation of renal drugs and experimental in- jury of the kidney. (authors)

Using resonance light scattering and UV/vis absorption spectroscopy to study the interaction between gliclazide and bovine serum albumin.

Science.gov (United States)

Zhang, Qiu-Ju; Liu, Bao-Sheng; Li, Gai-Xia; Han, Rong

2016-08-01

At different temperatures (298, 310 and 318 K), the interaction between gliclazide and bovine serum albumin (BSA) was investigated using fluorescence quenching spectroscopy, resonance light scattering spectroscopy and UV/vis absorption spectroscopy. The first method studied changes in the fluorescence of BSA on addition of gliclazide, and the latter two methods studied the spectral change in gliclazide while BSA was being added. The results indicated that the quenching mechanism between BSA and gliclazide was static. The binding constant (Ka ), number of binding sites (n), thermodynamic parameters, binding forces and Hill's coefficient were calculated at three temperatures. Values for the binding constant obtained using resonance light scattering and UV/vis absorption spectroscopy were much greater than those obtained from fluorescence quenching spectroscopy, indicating that methods monitoring gliclazide were more accurate and reasonable. In addition, the results suggest that other residues are involved in the reaction and the mode 'point to surface' existed in the interaction between BSA and gliclazide. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Reabsorption kinetics of albumin from pleural space of dogs

International Nuclear Information System (INIS)

Miniati, M.; Parker, J.C.; Pistolesi, M.; Cartledge, J.T.; Martin, D.J.; Giuntini, C.; Taylor, A.E.

1988-01-01

The reabsorption of albumin from the pleural space was measured in eight dogs receiving 0.5 ml intrapleural injection of 131 I-labeled albumin and a simultaneous intravenous injection of 125 I-labeled albumin. Plasma curves for both tracers were obtained over 24 h. The 125 I-albumin curve served as input function of albumin for interstitial spaces, including pleura, whereas the 131 I-albumin curve represented the output function from pleural space. The frequency function of albumin transit times from pleural space to plasma was obtained by deconvolution of input-output plasma curves. Plasma recovery of 131 I-albumin was complete by 24 h, and the mean transit time from pleura to plasma averaged 7.95 +/- 1.57 (SD) h. Albumin reabsorption occurred mainly via lymphatics as indicated by experiments in 16 additional dogs in which their right lymph ducts or thoracic ducts were ligated before intrapleural injection. A pleural lymph flow of 0.020 +/- 0.003 (SD) ml.kg-1.h-1 was estimated, which is balanced by a comparable filtration of fluid into the pleural space. This suggests that, under physiological conditions, the subpleural lymphatics represent an important control mechanism of pleural liquid pressure

Albumin synthesis in protein energy malnutrition

Energy Technology Data Exchange (ETDEWEB)

Duggan, C; Hardy, S; Kleinman, R E [Harvard Medical School, Boston, MA (United States); Lembcke, J [Instituto de Investigacion Nutricional, La Molina, Lima (Peru); Young, V E [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Lab. of Human Nutrition

1994-12-31

The dietary treatment of protein-energy malnutrition (PEM) has been designed on an empirical basis, with outcomes for successful management including body weight gain and resolution of apathy. We propose using the measurements of protein synthesis as a more objective measure of renourishment. We will therefore randomize a group of malnourished children (weigh-for-height Z score <-2.0) to receive either a standard (10% of calories as protein) or increased (15%) amount of dietary protein early in their recovery phase. We will calculate albumin synthesis rates via the flooding dose technique, using {sup 13}C-leucine and serial measurements of {sup 13}C-enrichment of albumin. Isotope infusions will be performed on days one and three, following a standard three hour fast. Since albumin synthesis is reduced under the influence of cytokines which mediate the inflammatory response, results will be stratified according to the presence or absence of clinically apparent infections. We hypothesize that the provision of added dietary protein will optimize albumin synthesis rates in PEM as well as attenuate the reduction in albumin synthesis seen in the presence of infections. (author). 20 refs.

Elucidation of intermolecular interaction of bovine serum albumin with Fenhexamid: A biophysical prospect.

Science.gov (United States)

Shi, Jie-Hua; Lou, Yan-Yue; Zhou, Kai-Li; Pan, Dong-Qi

2018-03-01

Fenhexamid, as a hydroxyanilide, is widely applied to control Botrytis cinerea for protecting crops and fruits. But it could adversely affect human and animals health due to accumulation of residues in food production. Here, the affinity characteristics of fenhexamid on bovine serum albumin (BSA) was studied via a series of spectroscopic methods such as steady-state fluorescence spectroscopy, ultraviolet spectroscopy (UV), synchronous fluorescence spectroscopy (SFS), 3D fluorescence spectroscopy, and fourier transform infrared spectroscopy (FT-IR). The experimental results illustrated that the fluorescence quenching mechanism of BSA induced by fenhexamid was a static quenching. The binding constant (K b ) of fenhexamid with BSA was 2.399 × 10 4  M -1 at 298 K and the combination ratio was about 1:1. The competitive experiment demonstrated that fenhexamid was binding on the BSA at site II (subdomain IIIA), which was confirmed by the molecular docking studies. The negative values of thermodynamic parameter (ΔH 0 , ΔS 0 and ΔG 0 ) revealed that the reaction of fenhexamid with BSA could proceed spontaneously, the van der Waals force and hydrogen bonding interaction conducted the main effect, and the binding process was enthalpy-driven. What's more, the 8-Anilino-1-naphthalenesulfonate (ANS) and sucrose binding studies were also performed and further verified the binding force between BSA and fenhexamid. Copyright © 2018 Elsevier B.V. All rights reserved.

Interactions of nanobubbles with bovine serum albumin and papain films on gold surfaces

Czech Academy of Sciences Publication Activity Database

Kolivoška, Viliam; Gál, Miroslav; Hromadová, Magdaléna; Lachmanová, Štěpánka; Pospíšil, Lubomír

2011-01-01

Roč. 6, č. 4 (2011), s. 164-170 ISSN 1559-4106 R&D Projects: GA ČR GP203/09/P502; GA ČR GA203/09/0705; GA ČR GA203/08/1157; GA AV ČR IAA400400802 Institutional research plan: CEZ:AV0Z40400503 Keywords : nanobubbles * bovine serum albumin * gold surfaces Subject RIV: CG - Electrochemistry Impact factor: 3.118, year: 2010

Quantitative aspects of recognition of the antibiotic drug oxytetracycline by bovine serum albumin: Calorimetric and spectroscopic studies

Energy Technology Data Exchange (ETDEWEB)

Keswani, Neelam; Choudhary, Sinjan [Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076 (India); Kishore, Nand [Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076 (India)

2013-03-15

Highlights: ► Thermodynamics of oxytetracycline (OTC)-bovine serum albumin (BSA) binding addressed. ► ITC and fluorescence spectroscopic analysis provide values of binding constant. ► Binding is mainly ionic, hydrophobic with minor hydrogen bonding contribution. ► Quantitative effects of OTC on BSA stability provided by DSC. ► Preferential complexation of one domain of BSA by OTC at site II is suggested. -- Abstract: A quantitative understanding of the mode of interaction of drugs with target proteins provides a guide for the synthesis of new drug molecules. The binding of the antibiotic drug oxytetracycline with serum albumin has been studied by a combination of isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC), steady-state and time-resolved fluorescence spectroscopy, and circular dichroism spectroscopy. The values of the binding constant (K), enthalpy change (ΔH), entropy (ΔS), and stoichiometry of binding have been determined along with the associated conformational changes in the protein. Oxytetracycline binds to bovine serum albumin with a 1:1 stoichiometry and with a weakly temperature dependent association constant of 1.8 · 10{sup 4} at T = 298.15 K. The effect of ionic strength, tetrabutylammonium bromide, and sucrose on the thermodynamic parameters obtained from ITC and DSC measurements indicate involvement of predominantly ionic and hydrophobic interactions with a minor hydrogen bonding contribution in the drug-protein complexation. The DSC results on the binding of oxytetracycline with bovine serum albumin in the absence and presence of these additives provide quantitative information on the effect of drugs on the stability of bovine serum albumin, and suggest preferential complexation of one of the domains of the protein. The results further indicate that the drug occupies binding site II on bovine serum albumin.

Quantitative aspects of recognition of the antibiotic drug oxytetracycline by bovine serum albumin: Calorimetric and spectroscopic studies

International Nuclear Information System (INIS)

Keswani, Neelam; Choudhary, Sinjan; Kishore, Nand

2013-01-01

Highlights: ► Thermodynamics of oxytetracycline (OTC)-bovine serum albumin (BSA) binding addressed. ► ITC and fluorescence spectroscopic analysis provide values of binding constant. ► Binding is mainly ionic, hydrophobic with minor hydrogen bonding contribution. ► Quantitative effects of OTC on BSA stability provided by DSC. ► Preferential complexation of one domain of BSA by OTC at site II is suggested. -- Abstract: A quantitative understanding of the mode of interaction of drugs with target proteins provides a guide for the synthesis of new drug molecules. The binding of the antibiotic drug oxytetracycline with serum albumin has been studied by a combination of isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC), steady-state and time-resolved fluorescence spectroscopy, and circular dichroism spectroscopy. The values of the binding constant (K), enthalpy change (ΔH), entropy (ΔS), and stoichiometry of binding have been determined along with the associated conformational changes in the protein. Oxytetracycline binds to bovine serum albumin with a 1:1 stoichiometry and with a weakly temperature dependent association constant of 1.8 · 10 4 at T = 298.15 K. The effect of ionic strength, tetrabutylammonium bromide, and sucrose on the thermodynamic parameters obtained from ITC and DSC measurements indicate involvement of predominantly ionic and hydrophobic interactions with a minor hydrogen bonding contribution in the drug-protein complexation. The DSC results on the binding of oxytetracycline with bovine serum albumin in the absence and presence of these additives provide quantitative information on the effect of drugs on the stability of bovine serum albumin, and suggest preferential complexation of one of the domains of the protein. The results further indicate that the drug occupies binding site II on bovine serum albumin

NMR diffusion and relaxation studies of 2-nitroimidazole and albumin interactions

Science.gov (United States)

Wijesekera, Dj; Willis, Scott A.; Gupta, Abhishek; Torres, Allan M.; Zheng, Gang; Price, William S.

2018-03-01

Nitroimidazole derivatives are of current interest in the development of hypoxia targeting agents and show potential in the establishment of quantitative measures of tumor hypoxia. In this study, the binding of 2-nitroimidazole to albumin was probed using NMR diffusion and relaxation measurements. Binding studies were conducted at three different protein concentrations (0.23, 0.30 and 0.38 mM) with drug concentrations ranging from 0.005-0.16 M at 298 K. Quantitative assessments of the binding model were made by evaluating the number of binding sites, n, and association constant, K. These were determined to be 21 ± 3 and 53 ± 4 M- 1, respectively.

Drug binding properties of neonatal albumin

DEFF Research Database (Denmark)

Brodersen, R; Honoré, B

1989-01-01

Neonatal and adult albumin was isolated by gel chromatography on Sephacryl S-300, from adult and umbilical cord serum, respectively. Binding of monoacetyl-diamino-diphenyl sulfone, warfarin, sulfamethizole, and diazepam was studied by means of equilibrium dialysis and the binding data were analyzed...... by the method of several acceptable fitted curves. It was found that the binding affinity to neonatal albumin is less than to adult albumin for monoacetyl-diamino-diphenyl sulfone and warfarin. Sulfamethizole binding to the neonatal protein is similarly reduced when more than one molecule of the drug is bound...

LOCALIZATION OF POLYSOME-BOUND ALBUMIN AND SERINE DEHYDRATASE IN RAT LIVER CELL FRACTIONS

Science.gov (United States)

Ikehara, Yukio; Pitot, Henry C.

1973-01-01

The polysomes involved in albumin and serine dehydratase synthesis were identified and localized by the binding to rat liver polysomes of anti-rat serum albumin and anti-serine dehydratase [125I]Fab dimer and monomer. Techniques were developed for the isolation of undegraded free and membrane-bound polysomes and for the preparation of [125I]Fab monomers and dimers from the IgG obtained from the antisera to the two proteins, rat serum albumin and serine dehydratase. The distribution of anti-rat serum albumin [125I]Fab dimer in the polysome profile is in accordance with the size of polysomes that are expected to be synthesizing albumin. By direct precipitation, it has been demonstrated that nascent chains isolated from the membrane-bound polysomes by puromycin were precipitated by anti-rat serum albumin-IgG at a level of 5–6 times those released from free polysomes. Anti-rat serum albumin-[125I]Fab dimer reacted with membrane-bound polysomes almost exclusively compared to the binding of nonimmune, control [125I]Fab dimer; a significant degree of binding of anti-rat serum albumin-[125I]Fab to free polysomes was also obtained. The [125I]Fab dimer made from normal control rabbit serum does not react with polysomes from liver at all and this preparation will not interact with polysomes extracted from tissues that do not synthesize rat serum albumin. Both anti-serine dehydratase-[125I]Fab monomer and dimer react with free and bound polysomes from livers of animals fed a chow diet or those fed a high 90% protein diet and given glucagon. In the latter instance, however, it is clear that the majority of the binding occurs to the bound polysomes. Furthermore, the specificity of this reaction may be further shown by the use of kidney polysomes that do not normally synthesize serine dehydratase. When these latter polysomes are isolated, even after the addition of crude and purified serine dehydratase, no reaction with anti-serine dehydratase-Fab fragments could be

Albumin metabolism in health and disease

International Nuclear Information System (INIS)

Kirsch, R.E.; Saunders, S.J.; Brock, J.F.

1979-01-01

Studies performed at the University of Cape Town on the metabolism of albumin have been reviewed. The control of albumin metabolism in protein energy malnutrition, in acute exposure to alcohol and after partial hepatectomy in the rat is discussed

Albumin metabolism in health and disease

Energy Technology Data Exchange (ETDEWEB)

Kirsch, R E; Saunders, S J; Brock, J F [Cape Town Univ. (South Africa). Dept. of Medicine

1979-11-24

Studies performed at the University of Cape Town on the metabolism of albumin have been reviewed. The control of albumin metabolism in protein energy malnutrition, in acute exposure to alcohol and after partial hepatectomy in the rat is discussed.

2.6. Sorption of serum albumin by ethynyl-piperidol hydrogels

International Nuclear Information System (INIS)

Khalikov, D.Kh.

2012-01-01

The sorption of serum albumin by ethynyl-piperidol hydrogels was studied in this article. Albumins adsorption on the surface of solids was considered. The capacity of cross-linked ethynyl piperidol polymers to the serum albumin was considered as well. The kinetic curves of sorption of human serum albumin by triple copolymer of isopropenyl trimethyl ethynyl piperidol were constructed. Sorption activity of ethynyl-piperidol polymers depending on ph of solution of human serum albumin were defined. Influence of solution ionic strength on sorption of human serum albumin was defined as well. The desorption of human serum albumin from the complexes with hydrogels was examined.

Study of interaction of butyl p-hydroxybenzoate with human serum albumin by molecular modeling and multi-spectroscopic method

Energy Technology Data Exchange (ETDEWEB)

Wang Qin, E-mail: wqing07@lzu.c [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Zhang Yaheng, E-mail: zhangyah04@lzu.c [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Sun Huijun, E-mail: sun.hui.jun-04@163.co [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Chen Hongli, E-mail: hlchen@lzu.edu.c [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Chen Xingguo, E-mail: chenxg@lzu.edu.c [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China)

2011-02-15

Study of the interaction between butyl p-hydroxybenzoate (butoben) and human serum albumin (HSA) has been performed by molecular modeling and multi-spectroscopic method. The interaction mechanism was predicted through molecular modeling first, then the binding parameters were confirmed using a series of spectroscopic methods, including fluorescence spectroscopy, UV-visible absorbance spectroscopy, circular dichroism (CD) spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. The thermodynamic parameters of the reaction, standard enthalpy {Delta}H{sup 0} and entropy {Delta}S{sup 0}, have been calculated to be -29.52 kJ mol{sup -1} and -24.23 J mol{sup -1} K{sup -1}, respectively, according to the Van't Hoff equation, which suggests the van der Waals force and hydrogen bonds are the predominant intermolecular forces in stabilizing the butoben-HSA complex. Results obtained by spectroscopic methods are consistent with that of the molecular modeling study. In addition, alteration of secondary structure of HSA in the presence of butoben was evaluated using the data obtained from UV-visible absorbance, CD and FT-IR spectroscopies. - Research highlights: The interaction between butyl p-hydroxybenzoate with HSA has been investigated for the first time. Molecular modeling study can provide theoretical direction for experimental design. Multi-spectroscopic method can provide the binding parameters and thermodynamic parameters. These results are important for food safety and human health when using parabens as a preservative.

Interaction of Flavonoids from Woodwardia unigemmata with Bovine Serum Albumin (BSA): Application of Spectroscopic Techniques and Molecular Modeling Methods.

Science.gov (United States)

Ma, Rui; Pan, Hong; Shen, Tao; Li, Peng; Chen, Yanan; Li, Zhenyu; Di, Xiaxia; Wang, Shuqi

2017-08-09

Phytochemical investigation on the methanol extract of Woodwardia unigemmata resulted in the isolation of seven flavonoids, including one new flavonol acylglycoside ( 1 ). The structures of these compounds were elucidated on the basis of extensive spectroscopic analysis and comparison of literature data. The multidrug resistance (MDR) reversing activity was evaluated for the isolated compounds using doxorubicin-resistant K562/A02 cells model. Compound 6 showed comparable MDR reversing effect to verapamil. Furthermore, the interaction between compounds and bovine serum albumin (BSA) was investigated by spectroscopic methods, including steady-state fluorescence, synchronous fluorescence, circular dichroism (CD) spectroscopies, and molecular docking approach. The experimental results indicated that the seven flavonoids bind to BSA by static quenching mechanisms. The negative ΔH and ΔS values indicated that van der Waals interactions and hydrogen bonds contributed in the binding of compounds 2 - 6 to BSA. In the case of compounds 1 and 7 systems, the hydrophobic interactions play a major role. The binding of compounds to BSA causes slight changes in the secondary structure of BSA. There are two binding sites of compound 6 on BSA and site I is the main site according to the molecular docking studies and the site marker competitive binding assay.

Interaction of antihypertensive drug amiloride with metal ions in micellar medium using fluorescence spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Gujar, Varsha; Pundge, Vijaykumar; Ottoor, Divya, E-mail: divya@chem.unipune.ac.in

2015-05-15

Steady state and life time fluorescence spectroscopy have been employed to study the interaction of antihypertensive drug amiloride with biologically important metal ions i.e. Cu{sup 2+}, Fe{sup 2+}, Ni{sup 2+} and Zn{sup 2+} in various micellar media (anionic SDS (sodium dodecyl sulfate), nonionic TX-100 (triton X-100) and cationic CTAB (cetyl trimethyl ammonium bromide)). It was observed that fluorescence properties of drug remain unaltered in the absence of micellar media with increasing concentration of metal ions. However, addition of Cu{sup 2+}, Fe{sup 2+} and Ni{sup 2+} caused fluorescence quenching of amiloride in the presence of anionic micelle, SDS. Binding of drug with metal ions at the charged micellar interface could be the possible reason for this pH-dependent metal-mediated fluorescence quenching. There were no remarkable changes observed due to metal ions addition when drug was present in cationic and nonionic micellar medium. The binding constant and bimolecular quenching constant were evaluated and compared for the drug–metal complexes using Stern–Volmer equation and fluorescence lifetime values. - Highlights: • Interaction of amiloride with biologically important metal ions, Fe{sup 2+}, Cu{sup 2+}, Ni{sup 2+} and Zn{sup 2+}. • Monitoring the interaction in various micelle at different pH by fluorescence spectroscopy. • Micelles acts as receptor, amiloride as transducer and metal ions as analyte in the present system. • Interaction study provides pH dependent quenching and binding mechanism of drug with metal ions.

Interaction of antihypertensive drug amiloride with metal ions in micellar medium using fluorescence spectroscopy

International Nuclear Information System (INIS)

Gujar, Varsha; Pundge, Vijaykumar; Ottoor, Divya

2015-01-01

Steady state and life time fluorescence spectroscopy have been employed to study the interaction of antihypertensive drug amiloride with biologically important metal ions i.e. Cu 2+ , Fe 2+ , Ni 2+ and Zn 2+ in various micellar media (anionic SDS (sodium dodecyl sulfate), nonionic TX-100 (triton X-100) and cationic CTAB (cetyl trimethyl ammonium bromide)). It was observed that fluorescence properties of drug remain unaltered in the absence of micellar media with increasing concentration of metal ions. However, addition of Cu 2+ , Fe 2+ and Ni 2+ caused fluorescence quenching of amiloride in the presence of anionic micelle, SDS. Binding of drug with metal ions at the charged micellar interface could be the possible reason for this pH-dependent metal-mediated fluorescence quenching. There were no remarkable changes observed due to metal ions addition when drug was present in cationic and nonionic micellar medium. The binding constant and bimolecular quenching constant were evaluated and compared for the drug–metal complexes using Stern–Volmer equation and fluorescence lifetime values. - Highlights: • Interaction of amiloride with biologically important metal ions, Fe 2+ , Cu 2+ , Ni 2+ and Zn 2+ . • Monitoring the interaction in various micelle at different pH by fluorescence spectroscopy. • Micelles acts as receptor, amiloride as transducer and metal ions as analyte in the present system. • Interaction study provides pH dependent quenching and binding mechanism of drug with metal ions

Response of soil microbial communities and microbial interactions to long-term heavy metal contamination.

Science.gov (United States)

Li, Xiaoqi; Meng, Delong; Li, Juan; Yin, Huaqun; Liu, Hongwei; Liu, Xueduan; Cheng, Cheng; Xiao, Yunhua; Liu, Zhenghua; Yan, Mingli

2017-12-01

Due to the persistence of metals in the ecosystem and their threat to all living organisms, effects of heavy metal on soil microbial communities were widely studied. However, little was known about the interactions among microorganisms in heavy metal-contaminated soils. In the present study, microbial communities in Non (CON), moderately (CL) and severely (CH) contaminated soils were investigated through high-throughput Illumina sequencing of 16s rRNA gene amplicons, and networks were constructed to show the interactions among microbes. Results showed that the microbial community composition was significantly, while the microbial diversity was not significantly affected by heavy metal contamination. Bacteria showed various response to heavy metals. Bacteria that positively correlated with Cd, e.g. Acidobacteria_Gp and Proteobacteria_thiobacillus, had more links between nodes and more positive interactions among microbes in CL- and CH-networks, while bacteria that negatively correlated with Cd, e.g. Longilinea, Gp2 and Gp4 had fewer network links and more negative interactions in CL and CH-networks. Unlike bacteria, members of the archaeal domain, i.e. phyla Crenarchaeota and Euryarchaeota, class Thermoprotei and order Thermoplasmatales showed only positive correlation with Cd and had more network interactions in CH-networks. The present study indicated that (i) the microbial community composition, as well as network interactions was shift to strengthen adaptability of microorganisms to heavy metal contamination, (ii) archaea were resistant to heavy metal contamination and may contribute to the adaption to heavy metals. It was proposed that the contribution might be achieved either by improving environment conditions or by cooperative interactions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of albumin and dextrose concentration on ultrasound and microbubble mediated gene transfection in vivo.

Science.gov (United States)

Browning, Richard J; Mulvana, Helen; Tang, Meng-Xing; Hajnal, Jo V; Wells, Dominic J; Eckersley, Robert J

2012-06-01

Ultrasound and microbubble mediated gene transfection has great potential for site-selective, safe gene delivery. Albumin-based microbubbles have shown the greatest transfection efficiency but have not been optimised specifically for this purpose. Additionally, few studies have highlighted desirable properties for transfection specific microbubbles. In this article, microbubbles were made with 2% or 5% (w/v) albumin and 20% or 40% (w/v) dextrose solutions, yielding four distinct bubble types. These were acoustically characterised and their efficiency in transfecting a luciferase plasmid (pGL4.13) into female, CD1 mice myocardia was measured. For either albumin concentration, increasing the dextrose concentration increased scattering, attenuation and resistance to ultrasound, resulting in significantly increased transfection. A significant interaction was noted between albumin and dextrose; 2% albumin bubbles made with 20% dextrose showed the least transfection but the most transfection with 40% dextrose. This trend was seen for both nonlinear scattering and attenuation behaviour but not for resistance to ultrasound or total scatter. We have determined that the attenuation behaviour is an important microbubble characteristic for effective gene transfection using ultrasound. Microbubble behaviour can also be simply controlled by altering the initial ingredients used during manufacture. Copyright © 2012 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Albumin supplementation for hypoalbuminemia following burns: unnecessary and costly!

Science.gov (United States)

Melinyshyn, Alex; Callum, Jeannie; Jeschke, Marc C; Cartotto, Robert

2013-01-01

Following fluid resuscitation, patients with major burns frequently develop prolonged hypoalbuminemia. It is not known whether this should be corrected by albumin supplementation. The purpose of this study was to determine whether there are any benefits associated with albumin supplementation to correct hypoalbuminemia in burned adults. We conducted a retrospective comparison of patients with burns ≥ 20% TBSA admitted to an adult regional American Burn Association-verified burn center, from May 1, 2009, to September 30, 2010, where we did not routinely supplement albumin (control group), with patients admitted from October 1, 2010, to May 30, 2011, where we had instituted a protocol in which 5% human albumin was provided to maintain serum albumin levels >20 g/L (albumin group). Comparisons were made from postburn (PB) day 2 to day 30 inclusive. There were no significant differences between control (n = 26) and albumin (n = 17) in age (48 ± 15 vs 45 ± 21 years; P = .56), burn size (33 ± 13 vs 34 ± 13 %TBSA; P = .831), or full thickness burn size (19 ± 19 vs 23 ± 19 %TBSA; P = .581). Inhalation injury was significantly more frequent in the albumin group than in controls (71% vs 31%; P = .01). The groups did not differ significantly in need for admission escharotomy, admission Sequential Organ Failure Assessment (SOFA) score, number of surgical procedures/first 30 days, or 24 and 48 hours fluid resuscitation volume requirements. The overall mean daily serum albumin level from PB day 2 to 30 in the albumin group (26.9 ± 3.0 g/L) was significantly greater than in controls (21.9 ± 4.4 g/L; P patient per day). We conclude that routine supplementation of 5% human albumin to maintain a serum albumin level ≥ 20 g/L in burn patients is expensive and provides no benefit.

Bond of donor-acceptor interaction in metal-ligand system with energies of Fermi electrons

International Nuclear Information System (INIS)

Vlasov, Yu.V.; Khentov, V.Ya.; Velikanova, L.N.; Semchenko, V.V.

1993-01-01

Role of quantum nature of metal (W, Mo and others) in donor-acceptor interaction of metal salicylalaniline - aprotic solvent was discussed. The dependence of dissolution rate and activation energy of donor-acceptor interaction on electron energy was established

Caveolae-Mediated Endocytosis Is Critical for Albumin Cellular Uptake and Response to Albumin-Bound Chemotherapy.

Science.gov (United States)

Chatterjee, Moumita; Ben-Josef, Edgar; Robb, Ryan; Vedaie, Marall; Seum, Star; Thirumoorthy, Krishnan; Palanichamy, Kamalakannan; Harbrecht, Matthew; Chakravarti, Arnab; Williams, Terence M

2017-11-01

Nab-paclitaxel, a nanoparticle conjugate of paclitaxel to human albumin, exhibits efficacy in pancreatic cancer, non-small cell lung cancer and breast cancer. However, there is a lack of predictive biomarkers to identify patients who might benefit most from its administration. This study addresses this gap in knowledge by identifying that caveolin-1 (Cav-1) is a candidate mechanism-based biomarker. Caveolae are small membrane invaginations important for transendothelial albumin uptake. Cav-1, the principal structural component of caveolae, is overexpressed in the cancers noted above that respond to nab-paclitaxel. Thus, we hypothesized that Cav-1 may be critical for albumin uptake in tumors and perhaps determine their response to this drug. Cav-1 protein levels correlated positively with nab-paclitaxel sensitivity. RNAi-mediated attenuation of Cav-1 expression reduced uptake of albumin and nab-paclitaxel in cancer cells and rendered them resistant to nab-paclitaxel-induced apoptosis. Conversely, Cav-1 overexpression enhanced sensitivity to nab-paclitaxel. Selection for cellular resistance to nab-paclitaxel in cell culture correlated with a loss of Cav-1 expression. In mouse xenograft models, cancer cells, where Cav-1 was attenuated, exhibited resistance to the antitumor effects of nab-paclitaxel therapy. Overall, our findings suggest Cav-1 as a predictive biomarker for the response to nab-paclitaxel and other albumin-based cancer therapeutic drugs. Cancer Res; 77(21); 5925-37. ©2017 AACR . ©2017 American Association for Cancer Research.

Investigation of ionizing radiation effect on albumin aqueous solutions

International Nuclear Information System (INIS)

Sizikov, A.M.; Adeeva, L.N.; Ogryzkova, I.F.

1986-01-01

Gamma radiation effect on 0.1-0.5%-albumin aqueous solutions has been investigated; variations of viscosity and optical density of solutions at pH medium different values and completeness of protein separation owing to radiation coagulation have been determined. It is shown that due to radiation coagulation it is possible to quantitatively separate albumin from irradiated aqueous solutions. The albumin coagulation is caused by OH radicals the action of which on albumin macromolecules results in destruction of intramolecular bonds and albumin conformation transformations

Molecular interaction and energy transfer between human serum albumin and bioactive component Aloe dihydrocoumarin

Science.gov (United States)

Zhang, Xiu-Feng; Xie, Ling; Liu, Yang; Xiang, Jun-Feng; Li, Lin; Tang, Ya-Lin

2008-10-01

Aloe dihydrocoumarin is an antioxidant and a candidate of immunomodulatory drug on the immune system and can balance physiological reactive oxygen species (ROS) levels which may be useful to maintain homeostasis. In order to explore the mechanism of drug action at a molecular level, the binding of Aloe dihydrocoumarin with human serum albumin (HSA) has been investigated by fluorescence, ultraviolet (UV), circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy, fluorescence dynamics, and molecular dynamic docking for the first time. We observed a quenching of fluorescence of HSA in the presence of Aloe dihydrocoumarin and also analyzed the quenching results using the Stern-Volmer equation and obtained high affinity binding to HSA. A Förster type fluorescence resonance energy transfer mechanism is involved in this quenching of Trp fluorescence by Aloe dihydrocoumarin. From the CD and FT-IR results, it is apparent that the interaction of Aloe dihydrocoumarin with HSA causes a conformational change of the protein, with the loss of α-helix stability and the gain of β-sheet and β-turn content. Data obtained by fluorescence spectroscopy, fluorescence dynamics, CD, and FT-IR experiments along with the docking studies suggest that Aloe dihydrocoumarin binds to residues located in subdomain IIA of HSA.

Thermodynamics of binding interactions between extracellular polymeric substances and heavy metals by isothermal titration microcalorimetry.

Science.gov (United States)

Yan, Peng; Xia, Jia-Shuai; Chen, You-Peng; Liu, Zhi-Ping; Guo, Jin-Song; Shen, Yu; Zhang, Cheng-Cheng; Wang, Jing

2017-05-01

Extracellular polymeric substances (EPS) play a crucial role in heavy metal bio-adsorption using activated sludge, but the interaction mechanism between heavy metals and EPS remains unclear. Isothermal titration calorimetry was employed to illuminate the mechanism in this study. The results indicate that binding between heavy metals and EPS is spontaneous and driven mainly by enthalpy change. Extracellular proteins in EPS are major participants in the binding process. Environmental conditions have significant impact on the adsorption performance. Divalent and trivalent cations severely impeded the binding of heavy metal ions to EPS. Electrostatic interaction mainly attributed to competition between divalent cations and heavy metal ions; trivalent cations directly competed with heavy metal ions for EPS binding sites. Trivalent cations were more competitive than divalent cations for heavy metal ion binding because they formed complexing bonds. This study facilitates a better understanding about the interaction between heavy metals and EPS in wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Albumin synthesis in protein energy malnutrition

International Nuclear Information System (INIS)

Duggan, C.; Hardy, S.; Kleinman, R.E.; Lembcke, J.; Young, V.E.

1994-01-01

The dietary treatment of protein-energy malnutrition (PEM) has been designed on an empirical basis, with outcomes for successful management including body weight gain and resolution of apathy. We propose using the measurements of protein synthesis as a more objective measure of renourishment. We will therefore randomize a group of malnourished children (weigh-for-height Z score 13 C-leucine and serial measurements of 13 C-enrichment of albumin. Isotope infusions will be performed on days one and three, following a standard three hour fast. Since albumin synthesis is reduced under the influence of cytokines which mediate the inflammatory response, results will be stratified according to the presence or absence of clinically apparent infections. We hypothesize that the provision of added dietary protein will optimize albumin synthesis rates in PEM as well as attenuate the reduction in albumin synthesis seen in the presence of infections. (author). 20 refs

21 CFR 866.5040 - Albumin immunological test system.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Albumin immunological test system. 866.5040... (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunological Test Systems § 866.5040 Albumin immunological test system. (a) Identification. An albumin immunological test system is a device that consists of...

Comparative studies on drug binding to the purified and pharmaceutical-grade human serum albumins: Bridging between basic research and clinical applications of albumin.

Science.gov (United States)

Ashrafi-Kooshk, Mohammad Reza; Ebrahimi, Farangis; Ranjbar, Samira; Ghobadi, Sirous; Moradi, Nastaran; Khodarahmi, Reza

2015-09-01

Human serum albumin (HSA), the most abundant protein in blood plasma, is a monomeric multidomain protein that possesses an extraordinary capacity for binding, so that serves as a circulating depot for endogenous and exogenous compounds. During the heat sterilization process, the structure of pharmaceutical-grade HSA may change and some of its activities may be lost. In this study, to provide deeper insight on this issue, we investigated drug-binding and some physicochemical properties of purified albumin (PA) and pharmaceutical-grade albumin (PGA) using two known drugs (indomethacin and ibuprofen). PGA displayed significantly lower drug binding capacity compared to PA. Analysis of the quenching and thermodynamic parameters indicated that intermolecular interactions between the drugs and the proteins are different from each other. Surface hydrophobicity as well as the stability of PGA decreased compared to PA, also surface hydrophobicity of PA and PGA increased upon drugs binding. Also, kinetic analysis of pseudo-esterase activities indicated that Km and Vmax parameters for PGA enzymatic activity are more and less than those of PA, respectively. This in vitro study demonstrates that the specific drug binding of PGA is significantly reduced. Such studies can act as connecting bridge between basic research discoveries and clinical applications. Copyright © 2015 The International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

Spectroscopic study of interaction between osthole and human serum albumin: Identification of possible binding site of the compound

Energy Technology Data Exchange (ETDEWEB)

Bijari, Nooshin [Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Shokoohinia, Yalda [Department of Pharmacognosy and Biotechnology, Faculty of Pharmacy, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Ashrafi-Kooshk, Mohammad Reza; Ranjbar, Samira; Parvaneh, Shahram [Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Moieni-Arya, Maryam [Student Research Committee, Faculty of Pharmacy, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Khodarahmi, Reza, E-mail: rkhodarahmi@mbrc.ac.ir [Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Department of Pharmacognosy and Biotechnology, Faculty of Pharmacy, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of)

2013-11-15

The studies on the interaction between human serum albumin (HSA) and drugs have been an interesting research field in life science, chemistry and clinical medicine. Osthole possesses a variety of pharmacological activities including anti-tumor, anti-inflammation, anti-seizure, anti-hyperlipidemic and anti-osteoporosis effects. The interaction of osthole with HSA and its binding site in HSA by spectroscopic methods is the subject of this work. By monitoring the intrinsic fluorescence of the single Trp{sub 214} residue and performing site markers displacement measurements, the specific binding of osthole in the vicinity of Sudlow's site I of HSA has been clarified. The changes in the secondary structure of HSA after its complexation with ligand were studied with CD spectroscopy, which indicate that osthole induced only a slight decrease in the helix structural content of the protein. In addition, the mean distance between osthole and HSA fluorophores is estimated to be 4.96 nm using Föster's equation on the basis of the fluorescence energy transfer. Furthermore, the synchronous fluorescence spectra show that the microenvironment of the tryptophan residues does not have obvious changes. Osthole can quench the intrinsic fluorescence of HSA by dynamic quenching, and analysis of the thermodynamic parameters of binding showed that hydrophobic interactions play an important role in the stabilizing of the complex. Increase of protein surface hydrophobicity (PSH) was also observed upon the osthole binding. -- Highlights: • Hydrophobic interactions play an important role in osthole–HSA interaction. • Sudlow's I site is possible binding site of osthole. • Osthole inhibits esterase activity of HSA. • Osthole binding induces no gross protein structural changes.

Elastic interactions between hydrogen atoms in metals. II. Elastic interaction energies

International Nuclear Information System (INIS)

Shirley, A.I.; Hall, C.K.

1986-01-01

The fully harmonic lattice approximation derived in a previous paper is used to calculate the elastic interaction energies in the niobium-hydrogen system. The permanent-direct, permanent-indirect, induced-direct, and induced-indirect forces calculated previously each give rise to a corresponding elastic interaction between hydrogen atoms. The latter three interactions have three- and four-body terms in addition to the usual two-body terms. These quantities are calculated and compared with the corresponding two-body permanent elastic interactions obtained in the harmonic-approximation treatment of Horner and Wagner. The results show that the total induced elastic energy is approximately (1/3) the size of the total permanent elastic energy and opposite to it in sign. The total elastic energy due to three-body interactions is approximately (1/4) the size of the total two-body elastic energy, while the total four-body elastic energy is approximately 5% of the total two-body energy. These additional elastic energies are expected to have a profound effect on the thermodynamic and phase-change behavior of a metal hydride

Spectroscopic and molecular docking studies on the interaction of human serum albumin with copper(II) complexes

Science.gov (United States)

Guhathakurta, Bhargab; Pradhan, Ankur Bikash; Das, Suman; Bandyopadhyay, Nirmalya; Lu, Liping; Zhu, Miaoli; Naskar, Jnan Prakash

2017-02-01

Two osazone based ligands, butane-2,3-dione bis(2‧-pyridylhydrazone) (BDBPH) and hexane-3,4-dione bis(2‧-pyridylhydrazone) (HDBPH), were synthesized out of the 2:1 M Schiff base condensation of 2-hydrazino pyridine respectively with 2,3-butanedione and 3,4-hexanedione. The X-ray crystal structures of both the ligands have been determined. The copper(II) complex of HDBPH has also been synthesized and structurally characterized. HDBPH and its copper(II) complex have thoroughly been characterized through various spectroscopic and analytical techniques. The X-ray crystal structure of the copper complex of HDBPH shows that it is a monomeric Cu(II) complex having 'N4O2' co-ordination chromophore. Interaction of human serum albumin (HSA) with these ligands and their monomeric copper(II) complexes have been studied by various spectroscopic means. The experimental findings show that the ligands as well as their copper complexes are good HSA binders. Molecular docking investigations have also been done to unravel the mode of binding of the species with HSA.

Serum albumin--a non-saturable carrier

DEFF Research Database (Denmark)

Brodersen, R; Honoré, B; Larsen, F G

1984-01-01

The shape of binding isotherms for sixteen ligands to human serum albumin showed no signs of approaching saturation at high ligand concentrations. It is suggested that ligand binding to serum albumin is essentially different from saturable binding of substrates to enzymes, of oxygen to haemoglobi...

Bidirectional peritoneal transport of albumin in continuous ambulatory peritoneal dialysis

DEFF Research Database (Denmark)

Joffe, P; Henriksen, Jens Henrik Sahl

1995-01-01

The present study was undertaken in order to assess bidirectional peritoneal kinetics of albumin after simultaneous i.v. and i.p. injection of radioiodinated albumin tracers (125I-RISA and 131I-RISA) in eight clinically stable uraemic patients undergoing continuous ambulatory peritoneal dialysis...... (CAPD). The plasma volume, intravascular albumin mass (IVM), and overall extravasation rate of albumin were not significantly different from that found in healthy controls. Albumin flux from the plasma into the peritoneal cavity was 3.71 +/- 0.82 (SD) mumol/h, which was only 3% of the overall...... extravasation rate (137 +/- 52 mumol/h). Albumin flux from the peritoneal cavity into the plasma was substantially lower (0.22 +/- 0.07 mumol/h, P peritoneal accumulation of the albumin from plasma over 4 h was 14 +/- 3.2 mumol, which was significantly lower than the intraperitoneal albumin...

Amadori albumin in diabetic nephropathy

Directory of Open Access Journals (Sweden)

Km. Neelofar

2015-01-01

Full Text Available Nonenzymatic glycation of macromolecules in diabetes mellitus (DM is accelerated due to persistent hyperglycemia. Reducing sugar such as glucose reacts non enzymatically with free €- amino groups of proteins through series of reactions forming Schiff bases. These bases are converted into Amadori product and further into AGEs. Non enzymatic glycation has the potential to alter the biological, structural and functional properties of macromolecules both in vitro and in vivo. Studies have suggested that amadori as well as AGEs are involved in the micro-macro vascular complications in DM, but most studies have focused on the role of AGEs in vascular complications of diabetes. Recently putative AGE-induced patho-physiology has shifted attention from the possible role of amadori-modified proteins, the predominant form of the glycated proteins in the development of the diabetic complications. Human serum albumin (HSA, the most abundant protein in circulation contains 59 lysine and 23 arginine residues that could, in theory be involved in glycation. Albumin has dual nature, first as a marker of intermediate glycation and second as a causative agent of the damage of tissues. Among the blood proteins, hemoglobin and albumin are the most common proteins that are glycated. HSA with a shorter half life than RBC, appears to be an alternative marker of glycemic control as it can indicate blood glucose status over a short period (2-3 weeks and being unaffected by RBCs life span and variant haemoglobin, anemia etc which however, affect HbA1c. On the other hand, Amadori albumin may accumulate in the body tissues of the diabetic patients and participate in secondary complications. Amadori-albumin has potential role in diabetic glomerulosclerosis due to long term hyperglycaemia and plays an important role in the pathogenesis of diabetic nephropathy. This review is an approach to compile both the nature of glycated albumin as a damaging agent of tissues and as an

Characterization of interactions of simvastatin, pravastatin, fluvastatin, and pitavastatin with bovine serum albumin: multiple spectroscopic and molecular docking.

Science.gov (United States)

Shi, Jie-Hua; Wang, Qi; Pan, Dong-Qi; Liu, Ting-Ting; Jiang, Min

2017-05-01

The binding interactions of simvastatin (SIM), pravastatin (PRA), fluvastatin (FLU), and pitavastatin (PIT) with bovine serum albumin (BSA) were investigated for determining the affinity of four statins with BSA through multiple spectroscopic and molecular docking methods. The experimental results showed that SIM, PRA, FLU, and PIT statins quenched the intrinsic fluorescence of BSA through a static quenching process and the stable stains-BSA complexes with the binding constants in the order of 10 4  M -1 at 298 K were formed through intermolecular nonbond interaction. The values of ΔH 0 , ΔS 0 and ΔG 0 in the binding process of SIM, PRA, FLU, and PIT with BSA were negative at the studied temperature range, suggesting that the binding process of four statins and BSA was spontaneous and the main interaction forces were van der Waals force and hydrogen-bonding interactions. Moreover, the binding of four statins with BSA was enthalpy-driven process due to |ΔH°|>|TΔS°| under the studied temperature range. From the results of site marker competitive experiments and molecular docking, subdomain IIIA (site II) was the primary binding site for SIM, PRA, FLU, and PIT on BSA. The results of UV-vis absorption, synchronous fluorescence, 3D fluorescence and FT-IR spectra proved that the slight change in the conformation of BSA, while the significant changes in the conformation of SIM, PRA, FLU, and PIT drug in statin-BSA complexes, indicating that the flexibility of statin molecules plays an important role in increasing the stability of statin-BSA complexes.

Oblique interactions of detonation waves with explosive/metal interfaces

International Nuclear Information System (INIS)

Walsh, J.M.

1982-12-01

The interaction of a detonation wave with an explosive/metal interface is considered. Theoretical models are discussed, and calculated results are given for PBX 9501 onto uranium, tantalum, copper, 304 stainless steel, aluminum, and nickel. For PBX 9501 onto aluminum and copper, regular shock reflection (in the PBX 9501) at small angles changes to regular rarefaction reflection (Prandtl-Meyer flow) at large angles, and the curve of metal-shock pressure vs incidence angle is smooth. For the other metals, there is a discontinuity in shock pressure where low-angle, regular reflection transists to Mach reflection, and a smaller discontinuity where the Mach reflection changes back to high-angle regular reflection

A low-protein diet restricts albumin synthesis in nephrotic rats.

OpenAIRE

Kaysen, G A; Jones, H; Martin, V; Hutchison, F N

1989-01-01

High-protein diets increase albumin synthesis in rats with Heymann nephritis but albuminuria increases also, causing serum albumin concentration to be suppressed further than in nephrotic animals eating a low-protein diet. Experiments were designed to determine whether dietary protein augmentation directly stimulates albumin synthesis, or whether instead increased albumin synthesis is triggered by the decrease in serum albumin concentration. Evidence is presented that dietary protein augmenta...

Interactions between salt marsh plants and Cu nanoparticles - Effects on metal uptake and phytoremediation processes.

Science.gov (United States)

Andreotti, Federico; Mucha, Ana Paula; Caetano, Cátia; Rodrigues, Paula; Rocha Gomes, Carlos; Almeida, C Marisa R

2015-10-01

The increased use of metallic nanoparticles (NPs) raises the probability of finding NPs in the environment. A lot of information exists already regarding interactions between plants and metals, but information regarding interactions between metallic NPs and plants, including salt marsh plants, is still lacking. This work aimed to study interactions between CuO NPs and the salt marsh plants Halimione portulacoides and Phragmites australis. In addition, the potential of these plants for phytoremediation of Cu NPs was evaluated. Plants were exposed for 8 days to sediment elutriate solution doped either with CuO or with ionic Cu. Afterwards, total metal concentrations were determined in plant tissues. Both plants accumulated Cu in their roots, but this accumulation was 4 to 10 times lower when the metal was added in NP form. For P. australis, metal translocation occurred when the metal was added either in ionic or in NP form, but for H. portulacoides no metal translocation was observed when NPs were added to the medium. Therefore, interactions between plants and NPs differ with the plant species. These facts should be taken in consideration when applying these plants for phytoremediation of contaminated sediments in estuaries, as the environmental management of these very important ecological areas can be affected. Copyright © 2015 Elsevier Inc. All rights reserved.

Adherence of platelets to in situ albumin-binding surfaces under flow conditions: role of surface-adsorbed albumin

International Nuclear Information System (INIS)

Guha Thakurta, Sanjukta; Miller, Robert; Subramanian, Anuradha

2012-01-01

Surfaces that preferentially bind human serum albumin (HSA) were generated by grafting albumin-binding linear peptide (LP1) onto silicon surfaces. The research aim was to evaluate the adsorption pattern of proteins and the adhesion of platelets from platelet-poor plasma and platelet-rich plasma, respectively, by albumin-binding surfaces under physiological shear rate (96 and 319 s −1 ) conditions. Bound proteins were quantified using enzyme-linked immunosorbent assays (ELISAs) and two-dimensional gel electrophoresis. A ratio of ∼1000:100:1 of adsorbed HSA, human immunoglobulin (HIgG) and human fibrinogen (HFib) was noted, respectively, on LP1-functionalized surfaces, and a ratio of ∼5:2:1 of the same was noted on control surfaces, as confirmed by ELISAs. The surface-adsorbed von Willebrand factor was undetectable by sensitive ELISAs. The amount of adhered platelets correlated with the ratio of adsorbed HSA/HFib. Platelet morphology was more rounded on LP1-functionalized surfaces when compared to control surfaces. The platelet adhesion response on albumin-binding surfaces can be explained by the reduction in the co-adsorption of other plasma proteins in a surface environment where there is an excess of albumin molecules, coupled with restrictions in the conformational transitions of other surface-adsorbed proteins into hemostatically active forms. (paper)

Quantitative determination of albumin in microlitre amounts of rat serum: With a short note on serum albumin levels in ageing rats

NARCIS (Netherlands)

Leeuw-Israel, F.R. de; Arp-Neefjes, J.M.; Hollander, C.F.

1967-01-01

A simple dye binding method for determining rat serum albumin, which employs the anionic dye 2-(4′-hydroxybenzneeazo) benzoic acid (HBABA) is described. Albumin in 5μ1 of serum is determined colorimetrically. Purified rat albumin is used as a primary standard and rat serum as a reference sample.

Quantum Butterfly Effect in Weakly Interacting Diffusive Metals

Directory of Open Access Journals (Sweden)

Aavishkar A. Patel

2017-09-01

Full Text Available We study scrambling, an avatar of chaos, in a weakly interacting metal in the presence of random potential disorder. It is well known that charge and heat spread via diffusion in such an interacting disordered metal. In contrast, we show within perturbation theory that chaos spreads in a ballistic fashion. The squared anticommutator of the electron-field operators inherits a light-cone-like growth, arising from an interplay of a growth (Lyapunov exponent that scales as the inelastic electron scattering rate and a diffusive piece due to the presence of disorder. In two spatial dimensions, the Lyapunov exponent is universally related at weak coupling to the sheet resistivity. We are able to define an effective temperature-dependent butterfly velocity, a speed limit for the propagation of quantum information that is much slower than microscopic velocities such as the Fermi velocity and that is qualitatively similar to that of a quantum critical system with a dynamical critical exponent z>1.

Application of a new method for data analysis of isothermal titration calorimetry in the interaction between human serum albumin and Ni2+

International Nuclear Information System (INIS)

Saboury, Ali Akbar.

2003-01-01

The interaction of human serum albumin (HAS) with divalent nickel ion was studied by isothermal titration calorimetry (ITC) in 30 mM Tris buffer, pH 7.0. There is a set of eight identical and independent binding sites for nickel ions on the protein at the temperature of 300 K. A new calorimetric data analysis allows the determination of the complete set of thermodynamic parameters. The binding isotherm for nickel-HSA interaction is easily obtained by carrying out two different ITC experiments. In the first experiment, the enthalpy of binding for one mole of nickel ion to one mole of binding site on HSA (ΔH=-36.5 kJ) is obtained, and is used in a second experiment to determine the binding isotherm and to find the number of binding sites (g=8) and the equilibrium constant (K=0.57 μM -1 )

Glycated albumin: from biochemistry and laboratory medicine to clinical practice.

Science.gov (United States)

Dozio, Elena; Di Gaetano, Nicola; Findeisen, Peter; Corsi Romanelli, Massimiliano Marco

2017-03-01

This review summarizes current knowledge about glycated albumin. We review the changes induced by glycation on the properties of albumin, the pathological implications of high glycated albumin levels, glycated albumin quantification methods, and the use of glycated albumin as a complementary biomarker for diabetes mellitus diagnosis and monitoring and for dealing with long-term complications. The advantages and limits of this biomarker in different clinical settings are also discussed.

Human serum albumin interactions with C{sub 60} fullerene studied by spectroscopy, small-angle neutron scattering, and molecular dynamics simulations

Energy Technology Data Exchange (ETDEWEB)

Li, Song [Vanderbilt University, Department of Chemical and Biomolecular Engineering (United States); Zhao, Xiongce [NIDDK, National Institutes of Health (United States); Mo, Yiming [Institute of Agriculture, University of Tennessee (United States); Cummings, Peter T., E-mail: cummingspt@ornl.gov [Vanderbilt University, Department of Chemical and Biomolecular Engineering (United States); Heller, William T., E-mail: hellerwt@ornl.gov [Oak Ridge National Laboratory, Center for Structural Molecular Biology (United States)

2013-07-15

Concern about the toxicity of engineered nanoparticles, such as the prototypical nanomaterial C{sub 60} fullerene, continues to grow. While, evidence continues to mount that C{sub 60} and its derivatives may pose health hazards, the specific molecular interactions of these particles with biological macromolecules require further investigation. In this article, we report combined experimental and theoretical studies on the interaction of one of the most prevalent proteins in the human body, human serum albumin (HSA), with C{sub 60} in an aqueous environment. The C{sub 60}-HSA interaction was probed by circular dichroism (CD) spectroscopy, small-angle neutron scattering (SANS), and atomistic molecular dynamics (MD) simulations to understand C{sub 60}-driven changes in the structure of HSA in solution. The CD spectroscopy demonstrates that the secondary structure of the protein decreases in {alpha}-helical content in response to the presence of C{sub 60} (0.68 nm in diameter). Similarly, C{sub 60} produces subtle changes in the solution conformation of HSA (an 8.0 nm Multiplication-Sign 3.8 nm protein), as evidenced by the SANS data and MD simulations, but the data do not indicate that C{sub 60} changes the oligomerization state of the protein, such as by inducing aggregation. The results demonstrate that the interaction is not highly disruptive to the protein in a manner that would prevent it from performing its physiological function.

A structurally driven analysis of thiol reactivity in mammalian albumins.

Science.gov (United States)

Spiga, Ottavia; Summa, Domenico; Cirri, Simone; Bernini, Andrea; Venditti, Vincenzo; De Chiara, Matteo; Priora, Raffaella; Frosali, Simona; Margaritis, Antonios; Di Giuseppe, Danila; Di Simplicio, Paolo; Niccolai, Neri

2011-04-01

Understanding the structural basis of protein redox activity is still an open question. Hence, by using a structural genomics approach, different albumins have been chosen to correlate protein structural features with the corresponding reaction rates of thiol exchange between albumin and disulfide DTNB. Predicted structures of rat, porcine, and bovine albumins have been compared with the experimentally derived human albumin. High structural similarity among these four albumins can be observed, in spite of their markedly different reactivity with DTNB. Sequence alignments offered preliminary hints on the contributions of sequence-specific local environments modulating albumin reactivity. Molecular dynamics simulations performed on experimental and predicted albumin structures reveal that thiolation rates are influenced by hydrogen bonding pattern and stability of the acceptor C34 sulphur atom with donor groups of nearby residues. Atom depth evolution of albumin C34 thiol groups has been monitored during Molecular Dynamic trajectories. The most reactive albumins appeared also the ones presenting the C34 sulphur atom on the protein surface with the highest accessibility. High C34 sulphur atom reactivity in rat and porcine albumins seems to be determined by the presence of additional positively charged amino acid residues favoring both the C34 S⁻ form and the approach of DTNB. Copyright © 2011 Wiley Periodicals, Inc.

Interaction of hydrogen with metallic nanojunctions

Energy Technology Data Exchange (ETDEWEB)

Halbritter, Andras; Csonka, Szabolcs; Makk, Peter; Mihaly, Gyoergy [Electron Transport Research Group of the Hungarian Academy of Sciences and Department of Physics, Budapest University of Technology and Economics, 1111 Budapest (Hungary)

2007-03-15

We study the behavior of hydrogen molecules between atomic-sized metallic electrodes using the mechanically controllable break junction technique. We focus on the interaction H{sub 2} with monoatomic gold chains demonstrating the possibility of a hydrogen molecule being incorporated in the chain. We also show that niobium is strongly reactive with hydrogen, which enables molecular transport studies between superconducting electrodes. This opens the possibility for a full characterization of the transmission properties of molecular junctions with superconducting subgap structure measurements.

In-gel detection of esterase-like albumin activity: Characterization of esterase-free sera albumin and its putative role as non-invasive biomarker of hepatic fibrosis

Directory of Open Access Journals (Sweden)

Areeba Ahmad

2017-07-01

Full Text Available Albumin is a globular and un-glycosylated multifunctional plasma protein and thus correlated with several human diseases. Owing to esterase contamination, albumin levels are usually misleading. In this study, we propose methodical accuracy for albumin estimation taking healthy and fibrotic rats. Liver fibrosis in rats was generated by N′-Nitrosodimethylamine (NDMA (10 mg/kg body weight within three weeks followed by its confirmation through H&E and immunohistochemical staining for α-SMA expression. Animal sera were screened by native polyacrylamide gel electrophoresis (native-PAGE (7.5%. In-gel esterase-like albumin activity was detected using α- and β-naphthyl acetate (5.58 × 10−3 mM; pH 7.5 as substrate. Sera albumin was purified from unstained PA gel-slices through electroelution. Subsequent to conformation of albumin purity by its molecular weight determination using SDS–PAGE (10% and peptide mass fingerprinting by MALDI-TOF-MS, samples were treated with different concentrations of urea. Urea-treated albumins were screened for esterase activity, conformational change and, albumin levels by immunoblotting. Our results demonstrate that esterase-like albumin activity in rat sera albumin is located in domain-III. The esterase-like activity remains detectable up to 4 M urea, which diminishes with increasing urea concentrations. Further, immunoblotting of urea-treated albumin samples displays a significant decline in purified protein bands, indicating hypoalbuminemia during hepatic fibrosis in rats. In conclusion, the present approach of albumin separation and estimation is of potential interest and may be recommended for diagnostic purposes.

Generation of Urinary Albumin Fragments Does Not Require Proximal Tubular Uptake

OpenAIRE

Weyer, K.; Nielsen, R.; Christensen, E. I.; Birn, H.

2012-01-01

Urinary albumin excretion is an important diagnostic and prognostic marker of renal function. Both animal and human urine contain large amounts of albumin fragments, but whether these fragments originate from renal tubular degradation of filtered albumin is unknown. Here, we used mice with kidneys lacking megalin and cubilin, the coreceptors that mediate proximal tubular endocytosis of albumin, to determine whether proximal tubular degradation of albumin forms the detectable urinary albumin f...

Albumin Enhances Caspofungin Activity against Aspergillus Species by Facilitating Drug Delivery to Germinating Hyphae.

Science.gov (United States)

Ioannou, Petros; Andrianaki, Aggeliki; Akoumianaki, Tonia; Kyrmizi, Irene; Albert, Nathaniel; Perlin, David; Samonis, George; Kontoyiannis, Dimitrios P; Chamilos, Georgios

2015-12-07

The modest in vitro activity of echinocandins against Aspergillus implies that host-related factors augment the action of these antifungal agents in vivo. We found that, in contrast to the other antifungal agents (voriconazole, amphotericin B) tested, caspofungin exhibited a profound increase in activity against various Aspergillus species under conditions of cell culture growth, as evidenced by a ≥4-fold decrease in minimum effective concentrations (MECs) (P = 0. 0005). Importantly, the enhanced activity of caspofungin against Aspergillus spp. under cell culture conditions was strictly dependent on serum albumin and was not observed with the other two echinocandins, micafungin and anidulafungin. Of interest, fluorescently labeled albumin bound preferentially on the surface of germinating Aspergillus hyphae, and this interaction was further enhanced upon treatment with caspofungin. In addition, supplementation of cell culture medium with albumin resulted in a significant, 5-fold increase in association of fluorescently labeled caspofungin with Aspergillus hyphae (P hyphae. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Albumin Enhances Caspofungin Activity against Aspergillus Species by Facilitating Drug Delivery to Germinating Hyphae

Science.gov (United States)

Ioannou, Petros; Andrianaki, Aggeliki; Akoumianaki, Tonia; Kyrmizi, Irene; Albert, Nathaniel; Perlin, David; Samonis, George

2015-01-01

The modest in vitro activity of echinocandins against Aspergillus implies that host-related factors augment the action of these antifungal agents in vivo. We found that, in contrast to the other antifungal agents (voriconazole, amphotericin B) tested, caspofungin exhibited a profound increase in activity against various Aspergillus species under conditions of cell culture growth, as evidenced by a ≥4-fold decrease in minimum effective concentrations (MECs) (P = 0. 0005). Importantly, the enhanced activity of caspofungin against Aspergillus spp. under cell culture conditions was strictly dependent on serum albumin and was not observed with the other two echinocandins, micafungin and anidulafungin. Of interest, fluorescently labeled albumin bound preferentially on the surface of germinating Aspergillus hyphae, and this interaction was further enhanced upon treatment with caspofungin. In addition, supplementation of cell culture medium with albumin resulted in a significant, 5-fold increase in association of fluorescently labeled caspofungin with Aspergillus hyphae (P Aspergillus hyphae. PMID:26643329

Electron emission during multicharged ion-metal surface interactions

International Nuclear Information System (INIS)

Zeijlmans van Emmichoven, P.A.; Havener, C.C.; Hughes, I.G.; Overbury, S.H.; Robinson, M.T.; Zehner, D.M.; Meyer, F.W.

1992-01-01

The electron emission during multicharged ion-metal surface interactions will be discussed. The interactions lead to the emission of a significant number of electrons. Most of these electrons have energies below 30 eV. For incident ions with innershell vacancies the emission of Auger electrons that fill these vacancies has been found to occur mainly below the surface. We will present recently measured electron energy distributions which will be used to discuss the mechanisms that lead to the emission of Auger and of low-energy electrons

Constrained Photophysics of 5,7-dimethoxy-2,3,4,9-tetrahydro-1H-carbazol-1-one in the Bioenvironment of Serum Albumins: A Spectroscopic Endeavour Supported by Molecular Docking Analysis.

Science.gov (United States)

Mitra, Amrit Krishna; Sau, Abhishek; Pal, Uttam; Saha, Chandan; Basu, Samita

2017-07-01

This paper vividly indicates that steady state as well as time-resolved fluorescence techniques can serve as highly sensitive monitors to explore the interactions of 5,7-dimethoxy-2,3,4,9-tetrahydro-1H-carbazol-1-one with model transport proteins, bovine serum albumin (BSA) and human serum albumin (HSA). Besides these, we have used fluorescence anisotropy study to assess the degree of restrictions imparted by the micro-environments of serum albumins. Again, to speculate the triplet excited state interaction between such fluorophore and albumin proteins (BSA& HSA), laser flash-photolysis experiments have been carried out. Molecular docking experiments have also been performed to support the conclusions obtained from steady state experiments.

Synchrotron X-ray Investigations of Mineral-Microbe-Metal Interactions

International Nuclear Information System (INIS)

Kemner, Kenneth M.; O'Loughlin, Edward J.; Kelly, Shelly D.; Boyanov, Maxim I.

2005-01-01

Interactions between microbes and minerals can play an important role in metal transformations (i.e. changes to an element's valence state, coordination chemistry, or both), which can ultimately affect that element's mobility. Mineralogy affects microbial metabolism and ecology in a system; microbes, in turn, can affect the system's mineralogy. Increasingly, synchrotron-based X-ray experiments are in routine use for determining an element's valence state and coordination chemistry, as well as for examining the role of microbes in metal transformations.

Albumin grafting on biomaterial surfaces using gamma-irradiation

International Nuclear Information System (INIS)

Kamath, K.R.

1993-01-01

Surface modification has been used extensively in various fields to introduce desirable surface properties without affecting the bulk properties of the material. In the area of biomaterials, the approach of surface modification offers an effective alternative to the synthesis of new biomaterials. The specific objective of this study was to modify different biomaterial surfaces by albumin grafting to improve their blood compatibility. The modified surfaces were characterized for surface-induced platelet activation and thrombus formation. This behavior was correlated with the conditions used for grafting. In particular, albumin was functionalized to introduce pendant double bonds into the molecule. The functionalized albumin was covalently attached to various surfaces, such as dimethyldichlorosilane-coated glass, polypropylene, polycarbonate, poly(vinyl chloride), and polyethylene by gamma-irradiation. Platelet adhesion and activation on these surfaces was examined using video microscopy and scanning electron microscopy. The extent of grafting was found to be dependent on the albumin concentration used for adsorption and the gamma-irradiation time. Release of the grafted albumin during exposure to blood was minimal. The albumin-grafted fibers maintained their thromboresistant properties even after storage at elevated temperatures for prolonged time periods. Finally, the approach was used to graft albumin on the PLEXUS Adult Hollow Fiber Oxygenators (Shiley). The blood compatibility of the grafted oxygenators improved significantly when compared to controls

Albumin, in the Presence of Calcium, Elicits a Massive Increase in Extracellular Bordetella Adenylate Cyclase Toxin.

Science.gov (United States)

Gonyar, Laura A; Gray, Mary C; Christianson, Gregory J; Mehrad, Borna; Hewlett, Erik L

2017-06-01

Pertussis (whooping cough), caused by Bordetella pertussis , is resurging in the United States and worldwide. Adenylate cyclase toxin (ACT) is a critical factor in establishing infection with B. pertussis and acts by specifically inhibiting the response of myeloid leukocytes to the pathogen. We report here that serum components, as discovered during growth in fetal bovine serum (FBS), elicit a robust increase in the amount of ACT, and ≥90% of this ACT is localized to the supernatant, unlike growth without FBS, in which ≥90% is associated with the bacterium. We have found that albumin, in the presence of physiological concentrations of calcium, acts specifically to enhance the amount of ACT and its localization to the supernatant. Respiratory secretions, which contain albumin, promote an increase in amount and localization of active ACT that is comparable to that elicited by serum and albumin. The response to albumin is not mediated through regulation of ACT at the transcriptional level or activation of the Bvg two-component system. As further illustration of the specificity of this phenomenon, serum collected from mice that lack albumin does not stimulate an increase in ACT. These data, demonstrating that albumin and calcium act synergistically in the host environment to increase production and release of ACT, strongly suggest that this phenomenon reflects a novel host-pathogen interaction that is central to infection with B. pertussis and other Bordetella species. Copyright © 2017 American Society for Microbiology.

Characterization of 6-mercaptopurine binding to bovine serum albumin and its displacement from the binding sites by quercetin and rutin

Energy Technology Data Exchange (ETDEWEB)

Ehteshami, Mehdi [Nutrition Research Center, School of Health and Nutrition, Tabriz University of Medical Sciences, Tabriz 51644-14766 (Iran, Islamic Republic of); Rasoulzadeh, Farzaneh [Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz 51644-14766 (Iran, Islamic Republic of); Mahboob, Soltanali [Nutrition Research Center, School of Health and Nutrition, Tabriz University of Medical Sciences, Tabriz 51644-14766 (Iran, Islamic Republic of); Rashidi, Mohammad-Reza, E-mail: rashidi@tbzmed.ac.ir [Research Center for Pharmaceutical Nanotechnology, Tabriz University of Medical Sciences, Tabriz 51644-14766 (Iran, Islamic Republic of)

2013-03-15

Binding of a drug to the serum albumins as major serum transport proteins can be influenced by other ligands leading to alteration of its pharmacological properties. In the present study, binding characteristics of 6-mercaptopurine (6-MP) with bovine serum albumin (BSA) together with its displacement from its binding site by quercetin and rutin have been investigated by the spectroscopic method. According to the binding parameters, a static quenching component in overall dynamic quenching process is operative in the interaction between 6-MP and BSA. The binding of 6-MP to BSA occurred spontaneously due to entropy-driven hydrophobic interactions. The synchronous fluorescence spectroscopy study revealed that the secondary structure of BSA is changed in the presence of 6-MP and both Tyr and Trp residues participate in the interaction between 6-MP and BSA with the later one being more dominant. The binding constant value of 6-MP-BSA in the presence of quercetin and rutin increased. 6-MP was displaced by ibuprofen indicating that the binding site of 6-MP on albumin is site II. Therefore, the change of the pharmacokinetic and pharmacodynamic properties of 6-MP by quercetin and rutin through alteration of binding capacity of 6-MP to the serum albumin cannot be ruled out. In addition, the displacement study showed that 6-MP is located in site II of BSA. - Highlights: Black-Right-Pointing-Pointer Participation of both Tyr and particularly Trp residues in the interaction between 6-MP and BSA. Black-Right-Pointing-Pointer Involvement of a static quenching component in an overall dynamic quenching process. Black-Right-Pointing-Pointer Ability of quercetin and rutin to change the binding constants of 6-MP-BSA complex. Black-Right-Pointing-Pointer Binding of 6-MP to BSA through entropy-driven hydrophobic interactions.

Interaction of aconitine with bovine serum albumin and effect of atropine sulphate and glycyrrhizic acid on the binding

International Nuclear Information System (INIS)

Huang Yun; Cui Lijian; Wang Jianming; Huo Kun; Chen Chen; Zhan Wenhong; Wang Yongli

2012-01-01

The interaction of aconitine with bovine serum albumin (BSA) and effect of atropine sulphate and glycyrrhizic acid on binding constant, binding sites, and conformation were studied in an aqueous buffer solution (pH 7.40) by ultraviolet absorption and fluorescence spectroscopy. The study results show that aconitine quenched the endogenous fluorescence of BSA via a dynamic quenching procedure. Predominant intermolecular forces between aconitine and BSA were hydrophobic interactions, which stabilized the complex of aconitine–BSA. The distance between the donor and acceptor was 2.62 nm. The conformation of BSA was investigated by synchronous fluorescence techniques, indicating that the microenvironment around tryptophan (Trp) residues was changed. Furthermore, with the addition of atropine sulphate or glycyrrhizic acid, binding constant and the number of binding sites of aconitine to BSA were decreased, and the conformation had no change, which provide an important theoretical support for aconitine detoxification by atropine sulphate and glycyrrhizic acid. - Highlights: ► Effect of atropine or glycyrrhizic acid on aconitine–BSA binding. ► UV–vis absorption and fluorescence spectroscopic techniques used. ► Aconitine quenched BSA fluorescence via dynamic quenching with r=2.62 nm. ► Atropine sulphate and glycyrrhizic acid decreased K A and n of aconitine–BSA. ► Support for aconitine detoxification by atropine and glycyrrhizic acid.

Observation of metallic sphere–complex plasma interactions in microgravity

International Nuclear Information System (INIS)

Schwabe, M; Zhdanov, S; Hagl, T; Huber, P; Rubin-Zuzic, M; Zaehringer, E; Thomas, H M; Lipaev, A M; Molotkov, V I; Naumkin, V N; Fortov, V E; Vinogradov, P V

2017-01-01

The PK-3 Plus laboratory on board the International Space Station is used to study the interaction between metallic spheres and a complex plasma. We show that the metallic spheres significantly affect both the local plasma environment and the microparticle dynamics. The spheres charge under the influence of the plasma and repel the microparticles, forming cavities surrounding the spheres. The size of the cavity around a sphere is used to study the force balance acting on microparticles at the cavity edge. We show that the ion drag force and pressure force from other microparticles balances with the electric force acting from the sphere to within 20%. At intermediate distances from the sphere surface, the interaction between the microparticles and the metallic spheres is attractive due to the drag force stemming from the ions which are moving towards the highly charged spheres. The spheres thus strongly affect the plasma fluxes. This modification of the plasma flux can lead to an effective surface tension acting on the microparticles, and to the excitation of dust-density waves near the spheres, as the local electric field crosses a threshold. (paper)

Molecular interaction of 2,4-diacetylphloroglucinol (DAPG) with human serum albumin (HSA): The spectroscopic, calorimetric and computational investigation

Science.gov (United States)

Pragna Lakshmi, T.; Mondal, Moumita; Ramadas, Krishna; Natarajan, Sakthivel

2017-08-01

Drug molecule interaction with human serum albumin (HSA) affects the distribution and elimination of the drug. The compound, 2,4-diacetylphloroglucinol (DAPG) has been known for its antimicrobial, antiviral, antihelminthic and anticancer properties. However, its interaction with HSA is not yet reported. In this study, the interaction between HSA and DAPG was investigated through steady-state fluorescence, time-resolved fluorescence (TRF), circular dichroism (CD), Fourier transform infrared (FT-IR) spectroscopy, isothermal titration calorimetry (ITC), molecular docking and molecular dynamics simulation (MDS). Fluorescence spectroscopy results showed the strong quenching of intrinsic fluorescence of HSA due to interaction with DAPG, through dynamic quenching mechanism. The compound bound to HSA with reversible and moderate affinity which explained its easy diffusion from circulatory system to target tissue. The thermodynamic parameters from fluorescence spectroscopic data clearly revealed the contribution of hydrophobic forces but, the role of hydrogen bonds was not negligible according to the ITC studies. The interaction was exothermic and spontaneous in nature. Binding with DAPG reduced the helical content of protein suggesting the unfolding of HSA. Site marker fluorescence experiments revealed the change in binding constant of DAPG in the presence of site I (warfarin) but not site II marker (ibuprofen) which confirmed that the DAPG bound to site I. ITC experiments also supported this as site I marker could not bind to HSA-DAPG complex while site II marker was accommodated in the complex. In silico studies further showed the lowest binding affinity and more stability of DAPG in site I than in site II. Thus the data presented in this study confirms the binding of DAPG to the site I of HSA which may help in further understanding of pharmacokinetic properties of DAPG.

Preparation of S-sulfo albumin film and its cell adhesive property

International Nuclear Information System (INIS)

Yamazoe, Hironori; Yamauchi, Kiyoshi; Tanabe, Toshizumi

2009-01-01

Recently, large-scale production of the pharmaceutical grade recombinant human serum albumin was achieved, and several clinical trials have proved its safety and efficacy. Albumin is thought to be a candidate for a safe biopolymer sources for application to biomaterials. In this study, we treated albumin with sodium sulfite and sodium tetrathionate to give S-sulfo albumin, which was found to loose native albumin structure by CD spectra analysis and dye-binding assay. A water-insoluble S-sulfo albumin films were prepared by drying S-sulfo albumin solution and subsequent reformation of disulfide bonds by the oxidation with iodine. Ultimate strength, ultimate elongation and Young's modulus of S-sulfo albumin film prepared at room temperature were 3.3 ± 0.4 MPa, 30.8 ± 3.2% and 40.8 ± 3.3 MPa before oxidative treatment and changed to 13.8 ± 4.2 MPa, 5.6 ± 2.8% and 401.7 ± 15.3 MPa after oxidative treatment. When the film was prepared at 60 deg. C, similar tendency was observed. Thus, the disulfide bonds formation between albumin molecules by oxidative treatment converted the film stronger and stiffer. Cell adhesion and proliferation on the films were evaluated using mouse L929 fibroblast cells. Cell adhesion largely depended on the albumin structure; that is, cells did not attach to native albumin coated surfaces, while cell adhesion and proliferation occurred on the S-sulfo albumin films which lost their native albumin structure. Eighty percent of seeded cells were adhered on S-sulfo albumin films and proliferated well in a similar manner to those on the conventional culture dish. Our results indicate that S-sulfo albumin is a favorable cell culture substrate.

Ultrasound-assisted interaction between chlorin-e6 and human serum albumin: pH dependence, singlet oxygen production, and formulation effect

Science.gov (United States)

Mocanu, Mihaela N.; Yan, Fei

2018-02-01

The interaction between chlorin e6 (Ce6) and human serum albumin (HSA) in the presence and absence of ultrasound have been investigated by ultraviolet-visible absorption spectroscopy and fluorescence spectroscopy. Ce6 is found to bind strongly to HSA at or near physiological pH conditions, but the strength of the binding is significantly weakened at lower pHs. The intrinsic fluorescence of HSA is incrementally quenched with increasing concentration of Ce6, and the quenching is enhanced after exposure to high-frequency ultrasound. Our experimental results suggest that Ce6-induced sonodynamic oxidation of HSA is mainly mediated by singlet oxygen. The formulation of Ce6 by high molecular weight polyvinylpyrrolidone (PVP) increased its stability in aqueous solutions and its quantum yield of singlet oxygen under ultrasound irradiation.

An albumin-fixed membrane for the removal of protein-bound toxins

International Nuclear Information System (INIS)

Ge Dongtao; Wu Dewang; Shi Wei; Ma Yuanyuan; Tian Xiangdong; Liang Pengfei; Zhang Qiqing

2006-01-01

Established methods for kidney dialysis do not work for liver failure because kidney dialysis removes only water-soluble toxins, while the liver normally removes albumin-bound toxins. In the present study, a polysulfone dialysis membrane with a -OH reactive group was prepared by hydrolyzing the chloromethylated polysulfone membrane, and the bovine serum albumin molecules were fixed into the membrane with 1,1'-carbonyldiimidazole activation. The content of albumin of the albumin-fixed membrane was 121.3 mg (g membrane) -1 . The albumin-fixed dialysis membranes were used to remove protein-bound toxins, bilirubin, from the bilirubin-albumin solution. The transfer rate of bilirubin of the albumin-fixed membrane was obviously higher compared to the normal dialysis membrane. The clearance of bilirubin with the albumin-fixed membrane was 49.8%. The albumin-fixed membrane can easily be regenerated by the bovine serum albumin and NaOH solution. Regeneration of the membrane suggested good mechanical and chemical stability, as well as good clearance of bilirubin. In addition, the effects of membrane thickness and bilirubin initial concentration on the removal of bilirubin were discussed

Thrombin-induced increase in albumin permeability across the endothelium

International Nuclear Information System (INIS)

Garcia, J.G.; Siflinger-Birnboim, A.; Bizios, R.; Del Vecchio, P.J.; Fenton, J.W. II; Malik, A.B.

1986-01-01

We studied the effect of thrombin on albumin permeability across the endothelial monolayer in vitro. Bovine pulmonary artery endothelial cells were grown on micropore membranes. Morphologic analysis confirmed the presence of a confluent monolayer with interendothelial junctions. Albumin permeability was measured by the clearance of 125I-albumin across the endothelial monolayer. The control 125I-albumin clearance was 0.273 +/- 0.02 microliter/min. The native enzyme, alpha-thrombin (10(-6) to 10(-10) M), added to the luminal side of the endothelium produced concentration-dependent increases in albumin clearance (maximum clearance of 0.586 +/- 0.08 microliter/min at 10(-6) M). Gamma (gamma) thrombin (10(-6) M and 10(-8) M), which lacks the fibrinogen recognition site, also produced a concentration-dependent increase in albumin clearance similar to that observed with alpha-thrombin. Moreover, the two proteolytically inactive forms of the native enzyme, i-Pr2 P-alpha-thrombin and D-Phe-Pro-Arg-CH2-alpha-thrombin, increased the 125I-albumin clearance (0.610 +/- 0.09 microliter/min and 0.609 +/- 0.02 microliter/min for i-Pr2 P-alpha-thrombin and D-Phe-Pro-Arg-CH2-alpha-thrombin at 10(-6) M, respectively). Since the modified forms of thrombin lack the fibrinogen recognition and active serine protease sites, the results indicate that neither site is required for increased albumin permeability. The increase in albumin clearance with alpha-thrombin was not secondary to endothelial cell lysis because lactate dehydrogenase concentration in the medium following thrombin was not significantly different from baseline values. There was also no morphological evidence of cell lysis. Moreover, the increase in 125I-albumin clearance induced by alpha-thrombin was reversible by washing thrombin from the endothelium

Transfer of oleic acid between albumin and phospholipid vesicles

International Nuclear Information System (INIS)

Hamilton, J.A.; Cistola, D.P.

1986-01-01

The net transfer of oleic acid between egg phosphatidylcholine unilamellar vesicles and bovine serum albumin has been monitored by 13 C NMR spectroscopy and 90% isotopically substituted [1- 13 C]oleic acid. The carboxyl chemical shifts of oleic acid bound to albumin were different from those for oleic acid in phospholipid vesicles. Therefore, in mixtures of donor particles, the equilibrium distribution of oleic acid was determined from chemical shift and peak intensity data without separation of donor and acceptor particles. In a system containing equal masses of albumin and phospholipid and a stoichiometry of 4-5 mol of oleic acid per mol of albumin, the oleic acid distribution was pH dependent, with ≥80% of the oleic acid associated with albumin at pH 7.4; association was ≥90% at pH 8.0. Decreasing the pH below 7.4 markedly decreased the proportion of fatty acid bound to albumin. The distribution was reversible with pH and was independent of whether vesicles or albumin acted as a donor. These data suggest that pH may strongly influence the partitioning of fatty acid between cellular membranes and albumin. The 13 C NMR method is also advantageous because it provides information about the structural environments of oleic acid bound to albumin or phospholipid, the ionization state of oleic acid in each environment, and the structural integrity of the vesicles. In addition, minimum and maximum limits for the exchange rates of oleic acid among different environments were obtained from the NMR data

Albumin-derived peptides efficiently reduce renal uptake of radiolabelled peptides

International Nuclear Information System (INIS)

Vegt, Erik; Eek, Annemarie; Oyen, Wim J.G.; Gotthardt, Martin; Boerman, Otto C.; Jong, Marion de

2010-01-01

In peptide-receptor radionuclide therapy (PRRT), the maximum activity dose that can safely be administered is limited by high renal uptake and retention of radiolabelled peptides. The kidney radiation dose can be reduced by coinfusion of agents that competitively inhibit the reabsorption of radiolabelled peptides, such as positively charged amino acids, Gelofusine, or trypsinised albumin. The aim of this study was to identify more specific and potent inhibitors of the kidney reabsorption of radiolabelled peptides, based on albumin. Albumin was fragmented using cyanogen bromide and six albumin-derived peptides with different numbers of electric charges were selected and synthesised. The effect of albumin fragments (FRALB-C) and selected albumin-derived peptides on the internalisation of 111 In-albumin, 111 In-minigastrin, 111 In-exendin and 111 In-octreotide by megalin-expressing cells was assessed. In rats, the effect of Gelofusine and albumin-derived peptides on the renal uptake and biodistribution of 111 In-minigastrin, 111 In-exendin and 111 In-octreotide was determined. FRALB-C significantly reduced the uptake of all radiolabelled peptides in vitro. The albumin-derived peptides showed different potencies in reducing the uptake of 111 In-albumin, 111 In-exendin and 111 In-minigastrin in vitro. The most efficient albumin-derived peptide (peptide 6), was selected for in vivo testing. In rats, 5 mg of peptide 6 very efficiently inhibited the renal uptake of 111 In-minigastrin, by 88%. Uptake of 111 In-exendin and 111 In-octreotide was reduced by 26 and 33%, respectively. The albumin-derived peptide 6 efficiently inhibited the renal reabsorption of 111 In-minigastrin, 111 In-exendin and 111 In-octreotide and is a promising candidate for kidney protection in PRRT. (orig.)

Electret filter collects more exhaled albumin than glass condenser

Science.gov (United States)

Jia, Ziru; Liu, Hongying; Li, Wang; Xie, Dandan; Cheng, Ke; Pi, Xitian

2018-01-01

Abstract In recent years, noninvasive diagnosis based on biomarkers in exhaled breath has been extensively studied. The procedure of biomarker collection is a key step. However, the traditional condenser method has low efficacy in collecting nonvolatile compounds especially the protein biomarkers in breath. To solve this deficiency, here we propose an electret filter method. Exhaled breath of 6 volunteers was collected with a glass condenser and an electret filter. The amount of albumin was analyzed. Furthermore, the difference of exhaled albumin between smokers and nonsmokers was evaluated. The electret filter method collected more albumin than the glass condenser method at the same breath volume level (P albumin than nonsmokers were also observed (P albumin than nonsmokers. PMID:29384875

Binding of ethyl pyruvate to bovine serum albumin: Calorimetric, spectroscopic and molecular docking studies

Energy Technology Data Exchange (ETDEWEB)

Pathak, Mallika [Department of Chemistry, Miranda House, University of Delhi, Delhi 11007 (India); Mishra, Rashmi; Agarwala, Paban K. [Department of Radiation Genetics and Epigenetics, Division of Radioprotective Drug Development Research, Institute of Nuclear Medicine and Allied Sciences, Delhi 110054 (India); Ojha, Himanshu, E-mail: himanshu.drdo@gmail.com [Department of Radiation Genetics and Epigenetics, Division of Radioprotective Drug Development Research, Institute of Nuclear Medicine and Allied Sciences, Delhi 110054 (India); Singh, Bhawna [Department of Radiation Genetics and Epigenetics, Division of Radioprotective Drug Development Research, Institute of Nuclear Medicine and Allied Sciences, Delhi 110054 (India); Singh, Anju; Kukreti, Shrikant [Nucleic Acid Research Laboratory, Department of Chemistry, University of Delhi, Delhi 11007 (India)

2016-06-10

Highlights: • ITC study showed binding of ethyl pyruvate with BSA with high binding affinity. • Ethyl pyruvate binding caused conformation alteration of BSA. • Fluorescence quenching mechanism is static in nature. • Electrostatic, hydrogen bonding and hydrophobic forces involved in binding. • Docking confirmed role of electrostatic, hydrogen bonding and hydrophobic forces. - Abstract: Various in vitro and in vivo studies have shown the anti-inflammatory and anticancer potential role of ethyl pyruvate. Bio-distribution of drugs is significantly influenced by the drug-serum protein binding. Therefore, the binding mechanism of the ethyl pyruvate with bovine serum albumin was investigated using UV–vis absorption, fluorescence, circular dichroism, isothermal titration calorimetry and molecular docking techniques. Absorption and fluorescence quenching studies indicated the binding of ethyl pyruvate with protein. Circular dichroism spectra of bovine serum albumin confirmed significant change in the conformation of protein upon binding. Thermodynamic data confirmed that ethyl pyruvate binds to bovine serum albumin at the two different sites with high affinity. Binding of ethyl pyruvate to bovine serum albumin involves hydrogen bonding, van der Waal and hydrophobic interactions. Further, docking studies indicated that ethyl pyruvate could bind significantly at the three binding sites. The results will definitely contribute to the development of ethyl pyruvate as drug.

Capping of Silybin with β-Cyclodextrin Influences its Binding with Bovine Serum Albumin: A Study by Fluorescence Spectroscopy and Molecular Modeling

Energy Technology Data Exchange (ETDEWEB)

Natesan, Sudha; Sowrirajan, Chandrasekaran; Dhanaraj, Premnath; Enoch, Israel V. M. V. [Karunya Univ., Tamil Nadu (India)

2014-07-15

The association of silybin with β-cyclodextrin and its influence on silybin's binding with bovine serum albumin are reported. The stoichiometry, binding constant, and the structure of silybin-β-cyclodextrin inclusion complex are reported. The titrations of silybin with bovine serum albumin in the absence and presence of β-cyclodextrin are carried out and the differences in binding strengths are discussed. Molecular modeling is used to optimize the sites and mode of binding of silybin with bovine serum albumin. Forster resonance energy transfer is calculated and the proximity of interacting molecules is reported in the presence and absence of β-cyclodextrin.

Capping of Silybin with β-Cyclodextrin Influences its Binding with Bovine Serum Albumin: A Study by Fluorescence Spectroscopy and Molecular Modeling

International Nuclear Information System (INIS)

Natesan, Sudha; Sowrirajan, Chandrasekaran; Dhanaraj, Premnath; Enoch, Israel V. M. V.

2014-01-01

The association of silybin with β-cyclodextrin and its influence on silybin's binding with bovine serum albumin are reported. The stoichiometry, binding constant, and the structure of silybin-β-cyclodextrin inclusion complex are reported. The titrations of silybin with bovine serum albumin in the absence and presence of β-cyclodextrin are carried out and the differences in binding strengths are discussed. Molecular modeling is used to optimize the sites and mode of binding of silybin with bovine serum albumin. Forster resonance energy transfer is calculated and the proximity of interacting molecules is reported in the presence and absence of β-cyclodextrin

Half-metal phases in a quantum wire with modulated spin-orbit interaction

Science.gov (United States)

Cabra, D. C.; Rossini, G. L.; Ferraz, A.; Japaridze, G. I.; Johannesson, H.

2017-11-01

We propose a spin filter device based on the interplay of a modulated spin-orbit interaction and a uniform external magnetic field acting on a quantum wire. Half-metal phases, where electrons with only a selected spin polarization exhibit ballistic conductance, can be tuned by varying the magnetic field. These half-metal phases are proven to be robust against electron-electron repulsive interactions. Our results arise from a combination of explicit band diagonalization, bosonization techniques, and extensive density matrix renormalization group computations.

Absorptive-mediated endocytosis of cationized albumin and a beta-endorphin-cationized albumin chimeric peptide by isolated brain capillaries. Model system of blood-brain barrier transport

International Nuclear Information System (INIS)

Kumagai, A.K.; Eisenberg, J.B.; Pardridge, W.M.

1987-01-01

Cationized albumin (pI greater than 8), unlike native albumin (pI approximately 4), enters cerebrospinal fluid (CSF) rapidly from blood. This suggests that a specific uptake mechanism for cationized albumin may exist at the brain capillary wall, i.e. the blood-brain barrier. Isolated bovine brain capillaries rapidly bound cationized [ 3 H]albumin and approximately 70% of the bound radioactivity was resistant to mild acid wash, which is assumed to represent internalized peptide. Binding was saturable and a Scatchard plot gave a maximal binding capacity (Ro) = 5.5 +/- 0.7 micrograms/mgp (79 +/- 10 pmol/mgp), and a half-saturation constant (KD) = 55 +/- 8 micrograms/ml (0.8 +/- 0.1 microM). The binding of cationized [ 3 H]albumin (pI = 8.5-9) was inhibited by protamine, protamine sulfate, and polylysine (molecular weight = 70,000) with a Ki of approximately 3 micrograms/ml for all three proteins. The use of cationized albumin in directed delivery of peptides through the blood-brain barrier was examined by coupling [ 3 H]beta-endorphin to unlabeled cationized albumin (pI = 8.5-9) using the bifunctional reagent, N-succinimidyl 3-(2-pyridyldithio)proprionate. The [ 3 H]beta-endorphin-cationized albumin chimeric peptide was rapidly bound and endocytosed by isolated bovine brain capillaries, and this was inhibited by unlabeled cationized albumin but not by unconjugated beta-endorphin or native bovine albumin. Cationized albumin provides a new tool for studying absorptive-mediated endocytosis at the brain capillary and may also provide a vehicle for directed drug delivery through the blood-brain barrier

Absorptive-mediated endocytosis of cationized albumin and a beta-endorphin-cationized albumin chimeric peptide by isolated brain capillaries. Model system of blood-brain barrier transport

Energy Technology Data Exchange (ETDEWEB)

Kumagai, A.K.; Eisenberg, J.B.; Pardridge, W.M.

1987-11-05

Cationized albumin (pI greater than 8), unlike native albumin (pI approximately 4), enters cerebrospinal fluid (CSF) rapidly from blood. This suggests that a specific uptake mechanism for cationized albumin may exist at the brain capillary wall, i.e. the blood-brain barrier. Isolated bovine brain capillaries rapidly bound cationized (/sup 3/H)albumin and approximately 70% of the bound radioactivity was resistant to mild acid wash, which is assumed to represent internalized peptide. Binding was saturable and a Scatchard plot gave a maximal binding capacity (Ro) = 5.5 +/- 0.7 micrograms/mgp (79 +/- 10 pmol/mgp), and a half-saturation constant (KD) = 55 +/- 8 micrograms/ml (0.8 +/- 0.1 microM). The binding of cationized (/sup 3/H)albumin (pI = 8.5-9) was inhibited by protamine, protamine sulfate, and polylysine (molecular weight = 70,000) with a Ki of approximately 3 micrograms/ml for all three proteins. The use of cationized albumin in directed delivery of peptides through the blood-brain barrier was examined by coupling (/sup 3/H)beta-endorphin to unlabeled cationized albumin (pI = 8.5-9) using the bifunctional reagent, N-succinimidyl 3-(2-pyridyldithio)proprionate. The (/sup 3/H)beta-endorphin-cationized albumin chimeric peptide was rapidly bound and endocytosed by isolated bovine brain capillaries, and this was inhibited by unlabeled cationized albumin but not by unconjugated beta-endorphin or native bovine albumin. Cationized albumin provides a new tool for studying absorptive-mediated endocytosis at the brain capillary and may also provide a vehicle for directed drug delivery through the blood-brain barrier.

Study of the deuterated albumin by FT-IR spectroscopy

International Nuclear Information System (INIS)

Stoenescu, Daniela; Sahini, V.E.

2000-01-01

The albumin is a protein from the soluble or corpuscular protein class, which exists in cells, in dissolved state or in form of a hydrated gel. Proteins are essential constituents beside water, inorganic salts, lipids, carbon hydrates, vitamins, enzymes. The albumin is also a protein soluble in water and in diluted electrolyte solutions (acids, bases and salts). The investigation of the vibration isotopic effect has a great importance both for the diatomic molecules and for the polyatomic molecules. This paper is the first from a series of works which are intended to study the physico-chemical properties of the deuterated albumin and of the albumin solutions in heavy water by an isotopic exchange method. To put in evidence H-D exchange, the FT-IR spectroscopy is used when the deuterated albumin has different layer thickness. It is also of interest to elucidate the isotopic exchange between the hydrogen and oxygen atoms in bovine serum albumin macromolecules. (authors)

Role of albumin and its modifications in glomerular injury.

Science.gov (United States)

Agrawal, Shipra; Smoyer, William E

2017-08-01

Albuminuria is both a characteristic hallmark and a known risk factor for progressive glomerular disease. Although the molecular basis for a potential causative role for albuminuria in progressive chronic kidney disease remains poorly understood, there have been several recent advances in our understanding of the role of albumin, and its molecular modifications, in the development and progression of glomerular disease. This review discusses recent findings related to the ability of albumin and its associated factors to directly induce podocyte and glomerular injury. Additional recent studies confirming the ability and mechanisms by which podocytes endocytose albumin are also discussed. Lastly, we present several known molecular modifications in the albumin molecule itself, as well as substances bound to it, which may be important and potentially clinically relevant mediators of albumin-induced glomerular injury. These recent findings may create entirely new opportunities to develop novel future therapies directed at albumin that could potentially help reduce podocyte and renal tubular injury and slow the progression of chronic glomerular disease.

Biomolecule-coated metal nanoparticles on titanium.

Science.gov (United States)

Christensen, Stephen L; Chatt, Amares; Zhang, Peng

2012-02-07

Immobilizations of nanoparticles and biomolecules on biocompatible substrates such as titanium are two promising approaches to bringing new functionalities to Ti-based biomaterials. Herein, we used a variety of X-ray spectroscopic techniques to study and better understand metal-thiolate interactions in biofunctionalized metal nanoparticle systems supported on Ti substrates. Using a facile one-step procedure, a series of Au nanoparticle samples with varied biomolecule coatings ((2-mercatopropionyl)glycine (MPG) and bovine serum albumin (BSA)) and biomolecule concentrations are prepared. Ag and Pd systems are also studied to observe change with varying metal composition. The structure and properties of these biomolecule-coated nanoparticles are investigated with scanning electron microscopy (SEM) and element-specific X-ray techniques, including extended X-ray absorption fine structure (Au L(3)-edge), X-ray absorption near-edge structure (Au L(3), Ag L(3), Pd L(3), and S K-edge), and X-ray photoelectron spectroscopy (Au 4f, Ag 3d, Pd 3d, and S 2p core level). It was found that, by comparison of SEM and X-ray spectroscopy results, the coating of metal nanoparticles with varying model biomolecule systems can have a significant effect on both surface coverage and organization. This work offers a facile chemical method for bio- and nanofunctionalization of Ti substrates as well as provides a physical picture of the structure and bonding of biocoated metal nanoparticles, which may lead to useful applications in orthopedics and biomedicine.

The albumin of the brown trout (Salmo trutta) is a glycoprotein.

Science.gov (United States)

Metcalf, V J; Brennan, S O; Chambers, G K; George, P M

1998-07-28

The albumin from an Atlantic salmonid, the brown trout (Salmo trutta), is 1730 Da higher in molecular mass than the albumin from a Pacific salmonid, the chinook salmon (Oncorhynchus tshawytscha), at 65230 Da. Digestion with neuraminidase revealed that purified brown trout albumin contained sialic acid while chinook salmon albumin did not. Concanavalin A-sepharose affinity chromatography was used to purify a glycopeptide from a total tryptic digest of brown trout albumin. The mass of this glycopeptide (3815 Da) was determined by mass spectrometry, and the sequence largely confirmed by N-terminal sequencing. The identified sequence of IAHCCNQSYSM-, contains an Asn-Gln-Ser glycosylation site and is identical to residues 475-485 derived from the cDNA of the albumin from the Atlantic salmon, the closest relative of the brown trout. Glycosylation of albumin is very unusual, and has not been identified in either reptilian or mammalian albumins. The finding of a glycoalbumin in salmonids, ancient members of the teleost fish subclass, coupled with evidence of albumin glycosylation in the oldest vertebrates, agnathans, as well as amphibians, suggests that albumin was originally a glycoprotein, but lost this modification sometime between the divergence of amphibians and reptiles.

Distribution and degradation of albumin in extensive skin disease

DEFF Research Database (Denmark)

Worm, Anne-Marie; Taaning, E; Rossing, N

1981-01-01

The distribution and degradation of albumin were determined in twelve patients with extensive skin disease and in ten control subjects by measuring the metabolic turnover and transcapillary escape of 132 I-labelled albumin. The ratio of intravascular to total mass of albumin was normal. Thus...... the observed hypoalbuminaemia and the low intravascular mass reflect a reduced mass of total body albumin. The rate of synthesis was normal, but the transcapillary escape rate reflecting the microvascular leakiness to macromolecules, and the fractional disappearance rate were significantly higher...

Ultrasonic microdialysis coupled with capillary electrophoresis electrochemiluminescence study the interaction between trimetazidine dihydrochloride and human serum albumin.

Science.gov (United States)

Sun, Shuangjiao; Long, Chanjuan; Tao, Chunyao; Meng, Sa; Deng, Biyang

2014-12-03

The paper describes a homemade ultrasonic microdialysis device coupled with capillary electrophoresis electrochemiluminescence (CE-ECL) for studying the interaction between human serum albumin (HSA) and trimetazidine dihydrochloride (TMZ). The time required for equilibrium by ultrasonic microdialysis was 45min, which was far less than that by traditional dialysis (240min). It took 80min to achieve the required combination equilibrium by normal incubation and only 20min by ultrasonic. Compared with traditional dialysis, the use of ultrasonic microdialysis simplified experimental procedures, shortened experimental time and saved consumption of sample. A simple, sensitive and selective determination of TMZ was developed using CE-ECL and the parameters that affected ECL intensity were optimized. Under the optimized conditions, the linear range of TMZ was from 0.075 to 80μmol/L (r(2)=0.9974). The detection limit was 26nmol/L with RSD of 2.8%. The number of binding sites and binding constant were 1.54 and 15.17L/mol, respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

Human serum albumin binding of certain antimalarials

Science.gov (United States)

Marković, Olivera S.; Cvijetić, Ilija N.; Zlatović, Mario V.; Opsenica, Igor M.; Konstantinović, Jelena M.; Terzić Jovanović, Nataša V.; Šolaja, Bogdan A.; Verbić, Tatjana Ž.

2018-03-01

Interactions between eight in-house synthesized aminoquinolines, along with well-known chloroquine, and human serum albumin (HSA) have been studied by fluorescence spectroscopy. The synthesized aminoquinolines, despite being structurally diverse, were found to be very potent antimalarials. Fluorescence measurements indicate that three compounds having additional thiophene or benzothiophene substructure bind more strongly to HSA than other studied compounds. Competitive binding experiments indicate that these three compounds bind significantly stronger to warfarin compared to diazepam binding site. Fluorescence quenching at three temperatures (20, 25, and 37 °C) was analyzed using classical Stern-Volmer equation, and a static quenching mechanism was proposed. The enthalpy and entropy changes upon sulphur-containing compound-HSA interactions were calculated using Van't Hoff equation. Positive values of enthalpy and entropy changes indicate that non-specific, hydrophobic interactions are the main contributors to HSA-compound interaction. Molecular docking and calculated lipophilicity descriptors indicate the same, pointing out that the increased lipophilicity of sulphur-containing compounds might be a reason for their better binding to HSA. Obtained results might contribute to design of novel derivatives with improved pharmacokinetic properties and drug efficacy.

In vitro study on binding interaction of quinapril with bovine serum albumin (BSA) using multi-spectroscopic and molecular docking methods.

Science.gov (United States)

Shi, Jie-Hua; Pan, Dong-Qi; Jiang, Min; Liu, Ting-Ting; Wang, Qi

2017-08-01

The binding interaction between quinapril (QNPL) and bovine serum albumin (BSA) in vitro has been investigated using UV absorption spectroscopy, steady-state fluorescence spectroscopic, synchronous fluorescence spectroscopy, 3D fluorescence spectroscopy, Fourier transform infrared spectroscopy, circular dichroism, and molecular docking methods for obtaining the binding information of QNPL with BSA. The experimental results confirm that the quenching mechanism of the intrinsic fluorescence of BSA induced by QNPL is static quenching based on the decrease in the quenching constants of BSA in the presence of QNPL with the increase in temperature and the quenching rates of BSA larger than 10 10  L mol -1  s -1 , indicating forming QNPL-BSA complex through the intermolecular binding interaction. The binding constant for the QNPL-BSA complex is in the order of 10 5  M -1 , indicating there is stronger binding interaction of QNPL with BSA. The analysis of thermodynamic parameters together with molecular docking study reveal that the main binding forces in the binding process of QNPL with BSA are van der Waal's forces and hydrogen bonding interaction. And, the binding interaction of BSA with QNPL is an enthalpy-driven process. Based on Förster resonance energy transfer, the binding distance between QNPL and BSA is calculated to be 2.76 nm. The results of the competitive binding experiments and molecular docking confirm that QNPL binds to sub-domain IIA (site I) of BSA. It is confirmed there is a slight change in the conformation of BSA after binding QNPL, but BSA still retains its secondary structure α-helicity.

Interaction of calcium oxide with molten alkali metal chlorides

International Nuclear Information System (INIS)

Volkovich, A.V.; Zhuravlev, V.I.; Ermakov, D.S.; Magurina, M.V.

1999-01-01

Calcium oxide solubility in molten lithium, sodium, potassium, cesium chlorides and their binary mixtures is determined in a temperature range of 973-1173 K by the method of isothermal saturation. Mechanisms of calcium oxide interaction with molten alkali metal chlorides are proposed

Investigation of the Interaction between Patulin and Human Serum Albumin by a Spectroscopic Method, Atomic Force Microscopy, and Molecular Modeling

Directory of Open Access Journals (Sweden)

Li Yuqin

2014-01-01

Full Text Available The interaction of patulin with human serum albumin (HSA was studied in vitro under normal physiological conditions. The study was performed using fluorescence, ultraviolet-visible spectroscopy (UV-Vis, circular dichroism (CD, atomic force microscopy (AFM, and molecular modeling techniques. The quenching mechanism was investigated using the association constants, the number of binding sites, and basic thermodynamic parameters. A dynamic quenching mechanism occurred between HSA and patulin, and the binding constants (K were 2.60 × 104, 4.59 × 104, and 7.01 × 104 M−1 at 288, 300, and 310 K, respectively. Based on fluorescence resonance energy transfer, the distance between the HSA and patulin was determined to be 2.847 nm. The ΔG0, ΔH0, and ΔS0 values across various temperatures indicated that hydrophobic interaction was the predominant binding force. The UV-Vis and CD results confirmed that the secondary structure of HSA was altered in the presence of patulin. The AFM results revealed that the individual HSA molecule dimensions were larger after interaction with patulin. In addition, molecular modeling showed that the patulin-HSA complex was stabilized by hydrophobic and hydrogen bond forces. The study results suggested that a weak intermolecular interaction occurred between patulin and HSA. Overall, the results are potentially useful for elucidating the toxigenicity of patulin when it is combined with the biomolecular function effect, transmembrane transport, toxicological, testing and other experiments.

Study of albumin from beef blood serum in D{sub 2}O solutions; Badanie roztworow albuminy z surowicy wolowej w D{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

Lewandowska, D. [Inst. of Experimental Physics, Gdansk Univ. (Poland); Podoski, T. [Wyzsza Szkola Morska, Gdynia (Poland)

1994-12-31

Molecular dynamics of albumin obtained from beef blood serum have been investigated in heavy water solutions by means of NMR spectra. The chemical shifts as well as spin-lattice relaxation times have been measured. The number of water protons interacting with albumin molecule have been estimated. 9 refs, 2 figs, 3 tabs.