The hydroxylation of y-butyrobetaine (4-trimethylaminobutyrate) to carnitine (3-hydroxy-4-trimethylaminobutyrate) is catalyzed by a soluble enzyme from rat liver which has been partially purified. The enzyme which previously has been shown to require molecular oxygen and ferrous ion has a specific requirement for 2-ketoglutarate. Several reductams stimulate the formation of hydroxylated product...

A nuclease has been isolated from germinating wheat seedlings and purified over 830-fold. The purified preparation hydrolyzes denatured DNA, rRNA, and the 3’-phosphoester linkage of 3’-AMP at similar rates. The preparation exhibits no appreciable 5’.nucleotidase, phosphodiesterase, or phosphomonoesterase activity. The three enzyme activities have remained associated throughout a variety of puri...

Experiments are described which have led to the selective alkylation of a histidine residue in streptococcal proteinase without concomitant reaction with the single essential sulfhydry1 group. The reduced, active form of the enzyme was first treated with sodium tetrathionate to protect the sulfhydry1 group and to introduce a negative charge near the active center. The resulting inactive derivat...

Augmenter of Liver Regeneration (ALR) is a sulfhydryl oxidase carrying out fundamental functions facilitating protein disulfide bond formation. In mammals, it also functions as a hepatotrophic growth factor that specifically stimulates hepatocyte proliferation and promotes liver regeneration after liver damage or partial hepatectomy. Whether ALR also plays a role during vertebrate hepatogenesis...

The oxygen free radical system has been reported to be activated by influenza virus infection in the lungs. However, the involvement of oxygen radicals in viral myocarditis is still unknown. Captopril, an angiotensin-converting enzyme (ACE) inhibitor and potent free radical scavenger with a sulfhydryl group, was effective for the treatment of viral myocarditis, while enalapril, an ACE inhibitor...

Chocolate is a product consumed worldwide and it stands out for presenting an important amount of phenolic compounds. In this study, the total phenolic content and antioxidant activity in the cerebral cortex, hippocampus, and cerebellum of male Wistar rats when consuming different types of chocolate, including milk, semisweet, dark, and soy, was evaluated. The total polyphenols concentration an...

Since 1938 mammalian succinate dehydrogenase has been thought to contain thiol groups at the active site. This hypothesis was questioned recently, because irreversible inhibition by bromopyruvate and N-ethylmaleimide appeared not to satisfy the requisite criteria for reaction at the active site. These recent observations of incomplete inactivation of succinate dehydrogenase by N-ethylmaleimide ...

Exposure of Escherichia coli 2-oxo-4-hydroxyglutarate aldolase (4-hydroxy-2-oxoglutarate glyoxylate-lyase, EC 4.1.3.16) (molecular weight = 63 000) to phosphoric acid at pH 1.6 for 10 min at 4 degrees C causes 95% or greater inactivation. No significant effect on the rate or extent of inactivation is caused by varied aldolase concentrations or the presence of exogenous proteins. Chloride ion (5...

Since 1938 mammalian succinate dehydrogenase has been thought to contain thiol groups at the active site. This hypothesis was questioned recently, because irreversible inhibition by bromopyruvate and ZV-ethylmaleimide appeared not to satisfy the requisite criteria for reaction at the active site. These recent observations of incomplete inactivation of succinate dehydrogenase by N-ethylmaleimide...

QSOX1 (quiescin sulfhydryl oxidase 1) efficiently catalyses the insertion of disulfide bonds into a wide range of proteins. The enzyme is mechanistically well characterized, but its subcellular location and the identity of its protein substrates remain ill-defined. The function of QSOX1 is likely to involve disulfide formation in proteins entering the secretory pathway or outside the cell. In t...