In vitro studies demonstrate that the hydroxyl radical converts L-phenylalanine into m-tyrosine, an unnatural isomer of L-tyrosine. Quantification of m-tyrosine has been widely used as an index of oxidative damage in tissue proteins. However, the possibility that m-tyrosine might be generated oxidatively from free L-phenylalanine that could subsequently be incorporated into proteins as an L-tyr...

Phosphorylation of tyrosine residues by protein tyrosine kinases (PTK) and phosphotyrosine/Src homology 2 (SH2) domain interactions are crucial not only for signal transduction but also for regulation of PTK activity. Tyrosine residues also receive nitration and halogenation under oxidative conditions. It has been reported that nitration of tyrosine residue caused peptides to be a poor substrat...

Objective(s) Motility plays a major role in pathogenicity of Helicobacter pylori, yet there is  scarce data regarding its chemotactic behaviour. The present study was designed to investigate the chemotactic responses of local isolates of H. pylori towards various sugars, amino acids, as well as some other chemical substances. Materials and Methods Chemotaxis was assayed by a modified Adler’s...

Background: Uterine natural killer (uNK) cells are the most abundant leukocytes in pre-implantation endometrium and early pregnancy deciduas in humans and rodents. They are associated with structural changes in maternal spiral arteries but regulation of their re-cruitment and activation is incompletely understood. The major subpopulation of uNK cells in humans expresses CD56, the neural cell ad...

Abstract In this study, a four-enzyme cascade pathway was developed and reconstructed in vivo for the production of d - p -hydroxyphenylglycine (D-HPG), valuable intermediate used to produce ?-lactam antibiotics fine-chemical synthesis, from l -tyrosine. pathway, catalytic conversion 4-hydroxyphenylglyoxalate by meso -diaminopimelate dehydrogenase Corynebacterium glutamicum ( Cg DAPDH) identifi...

ECM = extracellular matrix; FAK = focal adhesion-associated tyrosine kinase; PTP = protein tyrosine phosphatase; RA = rheumatoid arthritis; SF = synovial fibroblast; Src-PTK = src protein tyrosine kinase.

BACKGROUND/AIMS Erythropoietin-resistance is an unsolved concern in the treatment of renal anaemia. We aimed to investigate the possible role of ortho- and meta-tyrosine - the hydroxyl free radical products of L-phenylalanine - in the development of erythropoietin-resistance. METHODS TF-1 erythroblast cell line was used. Cell concentration was determined on day 1; 2 and 3 by two independent o...

Protein tyrosine O-sulfation is a post-translational modification mediated by one of two Golgi tyrosylprotein sulfotransferases (TPST1 and TPST2) that catalyze the transfer of sulfate to tyrosine residues in secreted and transmembrane proteins. Tyrosine sulfation plays a role in protein-protein interactions in several well defined systems. Although dozens of tyrosine-sulfated proteins are known...