The stereochemistry of a variety of pyridoxal phosphate-mediated enzymic reactions has been studied using enzyme inhibitors that are stereospecifically labeled in the b-position with deuterium. A versatile synthesis has been developed to prepare a wide variety of stereospecifically labeled Dand L-amino acids and inhibitors. Investigation of the “turnover” of b-chloro-D-alanine and Dand L-serine...

A series of novel amino acid ureidoamides 4a-o were prepared from N-(1-benzotriazolecarbonyl)-amino acid chloride 3, derived from L-alanine, L-valine, L-leucine, D-phenylglycine and L-phenylalanine, and the corresponding aminoalcohols (2-amino-1-ethanol, 3-amino-1-propanol and 5-amino-1-pentanol). The compounds were fully characterized by standard spectroscopic methods (IR, H and C NMR) and the...

BACKGROUND HCV infections are a serious threat to public health. An important drug target is the NS3 protease, for which several inhibitors are in clinical trials. Because of the high mutation rate of the virus, resistance against any HCV-specific drug is likely to become a substantial problem. Structure-activity data for the major resistant variants are therefore needed to guide future designs...

background: nonalcoholic fatty liver disease (nafld) includes a group of chronic liver disorders caused by irregular accumulation of fat in liver tissue. the current study aimed to evaluate chemical composition and the effect of fruit extract and essential oil of pimpinella anisum in experimental model of nafld. materials and methods: sixty rats were randomly divided into ten groups, six in eac...

We isolated a thermophile, Bacillus sp. YM-1 which abundantly produced the thermostable D-amino acid aminotransferase (EC 2.6.1.21; D-AAT), and cloned the enzyme gene into E. coli. The primary structure of D-AAT was found to be homologous with that of branched-chain L-amino acid aminotransferase (EC 2.6.1.42; BCAT) of E. coli. Both enzymes are unique in their stereospecificity of proR C-4' hydr...

Dexamethasone, insulin, and serum induce an additive increase in the activity of tyrosine aminotransferase (L-tyrosine : Z-oxoglutarate aminotransferase, EC 2.6.1.5) in hepatoma cells in tissue culture. By the criteria of immunotitration, heat stability, and electrophoresis on polyacrylamide gels, we have shown previously that all three effecters increase the cellular concentration of the same ...

Guava leaves have been used to treat cough and pulmonary diseases; they have also served as anti inflammatory and haemostatic agent in china. This work is therefore aimed at investigating the effects of guava leaf extract on the liver enzymes of adult wistar rats. Twenty apparently healthy wistar rats were used for this study. They were allocated into four groups (A, B, C & D) of five animals e...

Reproducible induction of the enzyme tyrosine aminotransferase by dibutyryl cAMP (Bt2cAMP) in a line of HTC hepatoma cells in suspension culture requires that the cells be preinduced with dexamethasone, a synthetic glucocorticoid which itself induces tyrosine aminotransferase. Concentrations of dexamethasone that do not induce tyrosine aminotransferase fail to support Bt2cAMP induction, removal...

the activity of aspartate aminotransferase a vitamin b6 containing enzyme was measured in the laysed synaptosomes prepared from rat brain, during development. administration of vitamin b6 increased the enzyme activity throughout development. the stimulating effect of this vitamin was prevented when the animals were previously treated with d-penicillamine. however, penicillamine alone had no eff...