Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.3.5.5 (CPS)
 1,262 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of alloxan diabetes on citrulline formation from NH4Cl and bicarbonate was studied in rabbit liver mitochondria incubated with glutamate or succinate as respiratory substrate, as well as with exogenous ATP in the presence of uncoupler and oligomycin. In contrast to ornithine transcarbamoylase, the activity of carbamoyl-phosphate synthetase (ammonia) was higher in mitochondria from diabetic animals than in those from normal ones. In diabetic rabbits the rates of citrulline synthesis were stimulated under all conditions studied. In contrast, levels of N-acetylglutamate, an activator of carbamoyl-phosphate synthetase (ammonia), were significantly increased only in the presence of glutamate, while the highest rates of citrulline formation occurred in uncoupled mitochondria incubated with exogenous ATP as energy source. Treatment of animals with alloxan resulted in an increase of both the intramitochondrial ATP level and the rate of adenine nucleotide translocation across the mitochondrial membrane. The results indicate that the stimulation of citrulline formation in liver mitochondria of diabetic rabbits is mainly due to an increase in carbamoyl-phosphate synthetase (ammonia) activity and an elevation of content of intramitochondrial ATP, a substrate of this enzyme.
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PMID:The stimulatory effect of alloxan diabetes on citrulline formation in rabbit liver mitochondria. 397 23

Carbamoyl-phosphate synthetase II (glutamine-hydrolyzing) (EC 6.3.5.5) (synthetase II), is the first and rate-limiting enzyme in the de novo UMP biosynthetic pathway. The present investigation showed that insulin has a regulatory action on hepatic synthetase II activity. When diabetes was induced with injection of different doses of alloxan the plasma insulin concentrations decreased in a dose-dependent fashion to 72, 38, 31 and 28% and concurrently the liver synthetase II activity decreased to 75, 43, 29 and 22% of the normal values. In diabetic rats dose response studies showed that with insulin injections of 4, 6, 8 or 10 U/day for 48 h the hepatic synthetase II activity increased to 81, 95, 99 and 103% of the control liver values. In the diabetic rats the insulin-induced rise in liver synthetase II activity was prevented by treatment of the rats with actinomycin.
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PMID:Action of insulin on liver carbamoyl-phosphate synthetase II (glutamine-hydrolyzing) activity. 634 26

1. The activities of enzymes of the urea cycle [carbamoyl phosphate synthetase, ornithine transcarbamoylase, argininosuccinate synthetase, argininosuccinase (these last two comprising the arginine-synthetase system) and arginase] have been measured in control, alloxan-diabetic and glucagon-treated rats. In addition, measurements were made on alloxan-diabetic rats treated with protamine-zinc-insulin. 2. Treatment of rats with glucagon for 3 days results in a marked increase in the activities of three enzymes of the urea cycle (carbamoyl phosphate synthetase, argininosuccinate synthetase and argininosuccinase). The pattern of change in the alloxan-diabetic group is very similar to that of the glucagon-treated group, although the magnitude of the change was much greater. 3. Comparison was made of the actual and potential rate of urea synthesis in normal and diabetic rats. In both groups the potential rate of urea production, as measured by the activity of the rate-limiting enzyme, argininosuccinate synthetase, slightly exceeds the actual rate of synthesis by liver slices in the presence of substrates. The relative activities of the actual and potential rates were similar in the two groups of animals, this ratio being 1:0.70. 4. In the alloxan-diabetic rats treated with protamine-zinc-insulin for 2.5 or 4 days there was a marked increase in liver weight. This was associated with a rise in the total hepatic activity of the urea-cycle enzymes located in the soluble fraction of the cell (the arginine-synthetase system and arginase) after 2.5 days of treatment. After 4 days of treatment the concentration of these enzymes/g. of liver decreased, and the total hepatic content then reverted to the untreated alloxan-diabetic value. 5. No effects of glucagon or of insulin in vitro could be found on the rate of urea production by liver slices. 6. The present results are discussed in relation to how far this pattern of change is typical of conditions resulting in a high urea output, and comparison has been made with other values in the literature.
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PMID:INFLUENCE OF PANCREATIC HORMONES ON ENZYMES CONCERNED WITH UREA SYNTHESIS IN RAT LIVER. 1434 1