UK PubMed Central (United Kingdom)

The activity of Src-related protein-tyrosine kinases is repressed by the phosphorylation of a conserved carboxyl-terminal tyrosine by another cytoplasmic protein-tyrosine kinase termed p50csk. In this...Full Text Available

UK PubMed Central (United Kingdom)

This study was designed to evaluate the suitability of a novel bioabsorbable material in treating bone defects. A poly(desaminotyrosyl-tyrosine-ethyl ester carbonate) (PDTE carbonate) membrane (thickness...Full Text Available

UK PubMed Central (United Kingdom)

The incorporation of [¹⁴C]phenylalanine and [1,6-¹⁴C]shikimic acid into tyrosine was investigated in the callus of Portulaca grandiflora, var. JR (L.). By inhibiting...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

With the mentioned method to analyse O-tyrosine with HPLC/fluorescence-detection, the irradiation of chicken meat can be determined in a simple and fast way. The formation of o-tyrosine is proportional to the applied dose but because it is also depending on the applied dose rate and the temperature during the irradiation, it is not possible to control the irradiation dose. Since unirradiated chicken can contain little amounts of o-tyrosine and to confirm some results, a second method is needed. Together with one of the other mentioned methods (analysis of the volatiles or esr-spectroscopy) it is possible to recognize irradiated chicken with a high security. (author).

UK PubMed Central (United Kingdom)

1. A high degree of homology in the positions of tyrosine residues in glyceraldehyde 3-phosphate dehydrogenase from lobster and pig muscle, and from yeast, prompted an examination of the reactivity...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Abstract Imatinib mesylate is the first of a novel group of drugs that specifically target protein tyrosine kinases, which are central to the pathogenesis of human cancer. It has been approved for the treatment of chronic myeloid leukemia and gastrointestinal stromal tumor and has been found efficacious in other neoplastic diseases. Nilotinib and dasatinib, a second-generation of tyrosine kinase inhibitors (TKIs), were developed in response to findings of emerging imatinib resistance or intolerance to the drug. Cutaneous reactions are the most common nonhematologic side effect of these drugs, and their management is challenging especially in the absence of alternative anticancer agents. The present review focuses on the clinical characteristics and the hypothesized molecular pathogenesis o...

UK PubMed Central (United Kingdom)

BackgroundNFκB signaling is of paramount importance in the regulation of apoptosis, proliferation, and inflammatory responses during human development and homeostasis, as...Full Text Available

UK PubMed Central (United Kingdom)

Phenylketonuria (PKU) is a common genetic disorder in humans that arises from deficient activity of phenylalanine hydroxylase (PAH), which catalyzes the conversion of phenylalanine to tyrosine....Full Text Available

International Nuclear Information System (INIS)

Lysozyme dimers produced on oxidation of lysozyme with Br_2anion radicals in aqueous solutions exhibit a fluorescence spectrum (lambdasub(max) = 400 nm) closely similar to that of bi-tyrosine. This suggests that the dimer is likely to have a tyrosine-tyrosine bond resulting from the combination of tyrosine phenoxy radicals of two lysozyme molecules. Kinetic studies on dimer formation were made by measuring time-dependent fluorescence after pulsed-electron irradiation over wide pH range. The results lead to the following conclusions. The second-order growth of the dimer fluorescence observed at pH 10.7-12.5 reflects the combination process of the lysozyme radicals, which is rate-determining in the pH range. On the other hand, the first-order growth observed at pH 6.8-10.2 is attributable to the enolization of the keto-form of the dimer. A tentative reaction scheme is proposed for the dimer formation. (author).

UK PubMed Central (United Kingdom)

IntroductionTyrosine phosphorylated signal transducer and activator of transcription 3 (pStat3) is expressed in numerous cancers and is required for mediating tumorigenesis. Autocrine...Full Text Available

International Nuclear Information System (INIS)

The authors have demonstrated that induction of mitogenesis in human T lymphocytes is associated with the tyrosine phosphorylation of a 66KD soluble substrate-TPP 66. Since DMSO has been shown to be a non-specific stimulator of tyrosine protein kinases they have examined the effect of DMSO on both activation and tyrosine phosphorylation in human T cells. Human peripheral blood T lymphocytes were isolated by dextran sedimentation, Ficol/Paque centrifugation and nylon wool filtration. Phosphorylation was performed in cells incubated with ["3"2P] orthophosphate followed by DMSO for 30 min. TPP 66 was identified by 2-D PAGE, autoradiography, and HV electrophoresis of the hydrolyzed protein. Concentrations of DMSO from 1% to 50% induced the tyrosine phosphorylation of TPP 66 with maximal stimulation seen at 20%. DMSO alone did not activate the T cells (measured by ["3H] thymidine incorporation) when tested ...

British Library Electronic Table of Contents (United Kingdom)

A comparative study on the interaction of (PEG-co-P(FA/SC)-co-PEG) triblock copolymer with bovine and human insulins was carried out using isothermal titration calorimetry (ITC), circular dichroism (CD), and fluorescence spectroscopy. ITC data show that the copolymer has a low affinity for both proteins, with an association constant of about 7?9?103?M ?1. Results also show that binding is enthalpically driven, and disfavored by conformational entropy. CD spectroscopy studies reveal a small increase in the helical content and a decrease in ?-structure as well as random coil in both proteins. Acrylamide quenching experiments display reduced accessibility of tyrosines, while intrinsic fluorescence spectra show lower tyrosine emission. Furthermore, thermal unfolding experiments, studied by far...

UK PubMed Central (United Kingdom)

c-Jun N-terminal kinase 2 (JNK2) isoforms are transcribed from the jnk2 gene and are highly homologous with jnk1 and jnk3 transcriptional products....Full Text Available

British Library Electronic Table of Contents (United Kingdom)

A novel class of pyrrolidinyl-acetyleneic thieno[3,2-d]pyrimidines has been identified which potently inhibit the EGFR and ErbB-2 receptor tyrosine kinases. Synthetic modifications of the pyrrolidine carbamate moiety result in a range of effects on enzyme and cellular potency. In addition, the impact of the absolute stereochemical configuration on cellular potency and oral mouse pharmacokinetics is described.

UK PubMed Central (United Kingdom)

The ζ chain-associated 70-kDa protein (ZAP-70) of tyrosine kinase plays a critical role in T cell receptor-mediated signal transduction and the immune response. A high level of ZAP-70 expression...Full Text Available

International Nuclear Information System (INIS)

A mixture of aminoacids was irradiated by a scattered proton beam, its energy varying from 4 to 6.6 MeV, by doses up to 5 x 10"1"1 proton/cm"2 for studying the potentiality of abiogenic synthesis of biologically important compounds in space. It was ascertained that increase in the radiation dose and reduction of proton energy involve increase in effectiveness both of destruction of the initial aminoacid (tryptophan, tyrosine, glycine) and synthesis of the relevant dipeptide. Essential influence of mineral substrate on abiogenic synthesis of natural nucleotides under the action of diverse energy sources was pointed out

Science.gov (United States)

HEMATOLOGICAL MALIGNANCIES IN HUMANS TYPICALLY INVOLVE TWO TYPES OF GENETIC CHANGES: those that promote hematopoietic cell proliferation and survival (often the result of activation of tyrosine kinases) and those that impair hematopoietic cell differentiation (often the result of changes in transcription factors). The multi-stage erythroleukemia induced in mice by Friend spleen focus-forming virus (SFFV) is an excellent animal model for studying the molecular basis for both of these changes. Significant progress has been made in understanding the molecular basis for the multi-stage erythroleukemia induced by Friend SFFV. In the first stage of leukemia, the envelope protein encoded by SFFV interacts with and activates the erythropoietin (Epo) receptor and the receptor tyrosine kinase sf-Stk in erythroid cells, causing their Epo-independent proliferation, differentiation and survival. In the second stage, SFFV integration into the Sfpi1 locus ...

British Library Electronic Table of Contents (United Kingdom)

Fyn is a Src-family tyrosine kinase that affects long term potentiation (LTP), synapse formation, and learning and memory. Fyn is also implicated in dendritic spine formation both in vitro and in vivo. However, whether Fyn's regulation of dendritic spine formation is brain-region specific and age-dependent is unknown. In the present study, we systematically examined whether Fyn altered dendritic spine density and morphology in the cortex and hippocampus and if these effects were age-dependent. We found that Fyn knockout mice trended toward a decrease in dendritic spine density in cortical layers II/III, but not in the hippocampus, at 1month of age. Additionally, Fyn knockout mice had significantly decreased dendritic spine density in both the cortex and hippocampus at 3months and 1year, an...

Science.gov (United States)

The bed nucleus of the stria terminalis (BST) and the medial amygdala (MeA) are anatomically connected sites necessary for chemosensory regulation of social behaviors in rodents. Prairie voles (Microtus ochrogaster) are a valuable model for studying the neural regulation of social behaviors because, unlike many other rodents, they are gregarious, pair bond after copulating, and are biparental. We herein describe sex and species differences in immunoreactivity for tyrosine hydroxylase (TH), the rate-limiting enzyme for catecholamine synthesis, in the BST and MeA. Virgin male prairie voles had a large number of TH-immunoreactive cells in areas analogous to the rat principal nucleus of the BST (pBST) and the posterodorsal medial amygdala (MeAPd). Virgin female prairie voles had far fewer TH-immunoreactive cells in these sites ( approximately 17% of the number of cells as males in the pBST, approximately 35% of the number of cells in the MeAPd). A few TH-immunoreactive ...

Energy Technology Data Exchange (ETDEWEB)

Cell extracts of the thermophile Clostridium thermohydrosulfuricum catalyzed the phosphorylation by (..gamma..-/sup 32/P)ATP of several endogenous proteins with M/sub r/s between 13,000 and 100,000. Serine and tyrosine were the main acceptors. Distinct substrate proteins were found in the soluble (e.g., proteins p66, p63, and p53 of M/sub r/s 66,000, 63,000, and 53,000, respectively) and particulate (p76 and p30) fractions, both of which contained protein kinase and phosphatase activity. The soluble fraction suppressed the phosphorylation of particulate proteins and contained a protein kinase inhibitor. Phosphorylation of p53 was promoted by 10..mu..M fructose 1,6-bisphosphate or glucose 1,6-bisphosphate and suppressed by hexose monophosphates, whereas p30 and p13 were suppressed by 5 ..mu..M brain (but not spinach) calmodulin. Polyamines, including the odd polyamines characteristic of thermophiles, modulated the labeling of most of the phosphoproteins. Apart from ...

Energy Technology Data Exchange (ETDEWEB)

Until recently no active treatment for advanced or metastatic gastrointestinal stroma tumors (GIST) was available. The tyrosine kinase inhibitor imatinib has revolutionized the treatment of this disease and the median overall survival now reaches 5 years. The standard dose of imatinib is 400 mg per day. Locally advanced GIST should be treated with systemic therapy prior to surgical resection. Imatinib was recently licensed for adjuvant therapy following complete surgical removal of GIST in patients with a significant risk of recurrence. (orig.) [German] Bis vor einigen Jahren existierte keine wirksame systemische Therapie fuer fortgeschrittene oder metastasierte gastrointestinale Stromatumoren (GIST). Der Tyrosinkinaseinhibitor Imatinib hat die Behandlung dieser Tumoren revolutioniert, die mediane Ueberlebenszeit liegt heute bei etwa 5 Jahren. Die Standarddosierung von Imatinib betraegt initial 400 mg/Tag. Lokal fortgeschrittene Tumoren werden primaer systemisch ...

Energy Technology Data Exchange (ETDEWEB)

The human CDC25 tyrosine phosphatases trigger activation of CDC2 by removing inhibitory phosphates; thus the genes encoding these phosphatases may be suspected as potential oncogenes due to their role in promoting cell division. To date, three human CDC25 genes have been identified: CDC25A, B, and C. This communication describes the mapping of CDC25A to chromosome 3p21 and CDC25B to chromosome 20p13 by fluorescence in situ hybridization with confirmation by the polymerase chain reaction of hamster-human somatic cell hybrid DNA. 3p21 is near an area frequently involved in karyotypic abnormalities in renal carcinomas, small cell carcinomas of the lung, and benign tumors of the salivary gland. 20p13 does not seem to be a common area for karyotypic alteration in tumors. Mapping of these genes to their chromosomal loci may help identify tumors with abnormal regulation of CDC25 genes due to genomic alterations. 15 refs., 3 figs.

International Nuclear Information System (INIS)

The cellular transport systems and the transport kinetics of ["1"2"3I]IMT uptake into non-malignant extracranial cells were characterized for the first time. Human fibroblasts were chosen as non-malignant extracranial cells as they are found ubiquitous in the body. ["1"2"3I]IMT is exclusively transported into fibroblasts via the sodium independent system L. An apparent Michaelis constant K_m=116.2#+-#18.9 #mu#M and a maximum transport velocity V_m_a_x=191.6#+-#13.9 pmol * (10"6 cells)"-"1 * min"-"1 were calculated for the sodium-independent transport. These results were compared with those determined in two malignantly transformed extracranial cell lines, the human Ewing's sarcoma cell lines VH-64 and CADO-ES-1.

Energy Technology Data Exchange (ETDEWEB)

The authors have shown previously that the domain recognizing receptors on activated human platelets is located on the human fibrinogen {gamma} chain between residues 400 and 411. To study the correlation between the structure of this segment of the {gamma} chain and its reactivity toward receptors on ADP-activated human platelets, they designed a series of analogues containing replacements at 9 out of 12 positions. A double substitution of the normal His{sup 400}-His{sup 401} sequence by Ala-Ala reduced the inhibitory potency of the dodecapeptide 3-fold. When Lys{sup 406} was replaced by Arg, the inhibitory potency of the dodecapeptide decreased 15 times. On the other hand, substitution of Ala{sup 408} with Arg increased the inhibitory potency of the dodecapeptide 6-fold. A drastic decrease in the reactivity of the dodecapeptide toward platelet receptors was observed when Val{sup 411} was replaced by leucine or cysteine or tyrosine. A 3-fold decrease in reactivity ...

International Nuclear Information System (INIS)

The purified integral membrane protein, band 3, from human erythrocytes was inserted into egg lecithin liposomes. The insertion of band 3 was determined from thermal transition data from the analysis of the C-H stretching region bands recorded at temperatures from 25 to -22"oC. Raman spectra show that band 3 considerably broadens and lowers the thermal transition of egg lecithin liposomes, suggesting the insertion of band 3. The band 3-inserted liposomes were irradiated with gamma-rays (40 Gy) and the radiation target groups were determined by the analysis of the structural sensitive Raman bands in the 1600-1700 cm"-"1 (amide I), 1200-1300 cm"-"1 (amide III) and 550-1030 cm"-"1 (side chain amino groups) regions. The radiation-sensitive groups as identified from Raman spectra in the region 550-1030 cm"-"1 are tyrosines and cysteines. The radiation-induced changes in the secondary structure were determined from amide I and III bands. Quantitative estimation using the ...

Energy Technology Data Exchange (ETDEWEB)

When Silk fibre derived from Bombyx mori, a native biopolymer, was dissolved in highly concentrated neutral salts such as CaCl{sub 2}, the regenerated liquid silk, a gradually degraded peptide mixture of silk fibroin, could be obtained. The silk fibroin nanoparticles were prepared rapidly from the liquid silk by using water-miscible protonic and polar aprotonic organic solvents. The nanoparticles are insoluble but well dispersed and stable in aqueous solution and are globular particles with a range of 35-125 nm in diameter by means of TEM, SEM, AFM and laser sizer. Over one half of the {epsilon}-amino groups exist around the protein nanoparticles by using a trinitrobenzenesulfonic acid (TNBS) method. Raman spectra shows the tyrosine residues on the surface of the globules are more exposed than those on native silk fibers. The crystalline polymorph and conformation transition of the silk nanoparticles from random-coil and {alpha}-helix form (Silk I) into ...