White and red muscles of normal and genetically dystrophic chickens were compared with regards to activity levels of three soluble enzymes, glyceraldehyde-3-phosphate dehydrogenase, creatine phosphokinase, and acetyl phosphatase. In dystrophic white muscle (pectoral), activity of the two sulfhydryl enzymes, glyceraldehyde-3-phosphate dehydrogenase and creatine phosphokinase, was preferentially ...

Glycogen phosphorylase a and b are irreversibly inactivated by oxidation with the disulfide cystamine. The mechanism is complex and involves oxidation of at least two classes of sulfhydryl groups. The oxidation of one or more of the first class of 4 f 1 sulfhydryl groups is reversible, but the equilibrium constant for the oxidation is so unfavorable (1 X that the micromolar concentrations of cy...

Cytidine triphosphate synthetase detected earlier in crude rat liver extracts by other workers (HURLBERT, R. B., AND KAMMEN, H. O., J. Biol. Chem., 235, 443 (1960)) has been purified about 350-fold from rat and calf liver. The enzyme catalyzes the conversion of UTP to CTP in the presence of ATP, L-glutamine, Mg++ , and a sulfhydryl-containing compound. Although it is not an absolute requirement...

In the production of biological effects such as vesication by bis-p-chloroethyl sulfide (mustard gas) it has been considered probable that inactivation of tissue enzymes is of foremost importance. In view of the reaction characteristics of bis-p-chloroethyl sulfide it has appeared likely that this inhibition is due to an alkylation reaction involving essential groups of the enzymes. Involvement...

In Bacillus subtilis shikimate kinase enzyme activity can be demonstrated when a small polypeptide forms a trifunctional complex with the bifunctional enzyme 3-deoxy-D-arabinoheptulosonate-7-phosphate synthetase-chorismate mutase. The shikimate kinase polypeptide whoch carries the catalytic site has been purified to homogeneity by a five-step procedure. The skikimate kinase was determined to ha...

The middle T antigen (MT Ag) encoded by polyoma virus has an associated protein kinase activity which transfers a phosphoryl group from ATP or GTP to a tyrosine residue on MT Ag in immunoprecipitates formed between polyoma virus-infected or transformed cell extracts and serum from animals bearing polyoma-induced tumors. Incubation of such immunoprecipitates or polyoma-transformed cell extracts ...

The discovery of captopril, the prototype of orally active angiotensin-converting enzyme inhibitors (ACEIs), represented a major breakthrough in the treatment of cardiovascular diseases. Currently, captopril has four important indications: hypertension, congestive heart failure, acute myocardial infarction, and diabetic nephropathy. After the discovery of captopril, several new ACEIs were devel...

It is now generally agreed that papain possesses a single reactive sulfhydryl group which is essential for activity and which probably participates in the catalytic mechanism by forming acyl intermediates with the different substrates (2, 3). Smith (4) has claimed that the essential sulfhydryl group of papain is kinetically more active than most protein sulfhydryl groups and that it possesses d...