Pyr idoxa l phosphate, the cofactor of glycogen phosphorylase, fulfils the criteria needed of a turnover label for this enzyme. The decay of protein-bound label fo l lowing administration of [3H]pyridoxine is a good index of the rate of degradation of the enzyme in vivo. This m e t h o d has been applied to the s tudy of catabolism of the enzyme in normal, denervated and dys t roph ic mouse ske...

We found a family with a high activity for hydrolyzing L-alanyl-beta-naphthylamide in their serum. This enzyme was confirmed to be aminopeptidase (microsomal) (EC 3.4.11.2) by means of immunological experiments involving anti-human kidney aminopeptidase (microsomal) antibody. We could not find the cause of the increased activity from the results of clinical and laboratory examinations. The enzy...

The levels of pseudocholinesterase and its nature were studied in 390 leprosy patients and 343 control subjects. The levels of the enzyme in both leprosy patients and normal controls were comparable. The study of the nature of the enzyme by determining its dibucaine number showed that a statistically significant number of lepromatous patients had the atypical variety of the enzyme compared with...

Rat hepatoma cells were fused with cells of an established mouse lymphoma line, with normal diploid mouse macrophages, lymphocytes and fibroblasts and with normal diploid rat macrophages and lymphocytes. The liver-specific enzyme tyrosine aminotransferase was produced by almost all the hybrid cells, but usually at a lower level than in the parental hepatoma cells. Most of the hybrids also showe...

A double enzyme of Salmonella typhimuriwn, containing histidinol dehydrogenase and imidazolylacetolphosphate:~glutamate aminotransferase, was mildly proteolyzed in an attempt to release these activities from covalent linkage. This treatment releases an active histidinol dehydrogenase fragment larger than normal histidinol dehydrogenase, while completely destroying aminotransferase activity. The...

The enzyme carotenoid 15,15'-monooxygenase (CMO1) catalyzes the first step in the conversion of dietary provitamin A carotenoids to vitamin A in the small intestine. Plant carotenoids are an important dietary source of vitamin A (retinol) and the sole source of vitamin A for vegetarians. Vitamin A is essential for normal embryonic development as well as normal physiological functions in childre...

Human cytochome P450 2W1 (CYP2W1) enzyme is expressed in fetal colon and in colon tumors. The level of expression is higher in colon metastases than in the parent tumors and the enzyme is a possible drug target for treatment of colorectal cancer, as demonstrated in mouse xenograft studies. A previous study published in this journal reported that CYP2W1 is highly expressed in normal and transfor...

Captopril, an inhibitor of angiotensin converting enzyme, was administered twice daily to 13 hypertensive patients for a mean period of 9 weeks. Continuous blood pressure control in the ambulatory patients was established with a portable blood pressure recorder. Notwithstanding, in eight patients with normal renal function, plasma converting enzyme was found to resume normal activity before adm...