Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.4.1 (cytosine deaminase)
 747 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Uptake and intracellular transformation of pyrimidines supplying cells of the yeast Rhodotorula glutinis with nitrogen have been studied. The amine nitrogen of cytosine was found to be the easiest to utilize. The presence in the medium of inorganic ammonia along with cytosine had a slight effect on cytosine deaminase (EC 3.5.4.1) activity. The uracil produced entered into the nutrient medium with no fission break of the pyridmidine ring. In the absence of any other source of nitrogen, the cells of the yeast R. glutinis utilized nitrogen of the pyrimidine ring of oxypyrimidines. Catabolism of uracil followed the reductive pattern, with release of carbon dioxide; this was accompanied by synthesis of the key enzyme of pyrimidine catabolism, dihydrouracil dehydrogenase (EC 1.3.1.1), whose activity rose 10-fold. With thymidne as the sole source of nitrogen, the lag-phase growth of the yeast cells was maximum. Catabolism of the pyrimidine ring of thymine was possibly preceded by its transformation into uracil. With no source of nitrogen easily utilized, the uridine 5'-monophosphate content in the generally acid-soluble pool rose. Our discussion of the regulation of catabolism of exogenous pyrimidine bases by the yeast R. glutinis takes into account the fact that transformations of pyrimidine bases are determined by how easily the cells can use a particular base as a source of nitrogen.
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PMID:Utilization of exogenous pyrimidines as a source of nitrogen by cells of the yeast Rhodotorula glutinis. 94 62

A novel metabolic pathway for the degradation of creatinine with N-methylhydantoin, N-carbamoylsarcosine and sarcosine as successive intermediates was found to operate in Pseudomonas putida 77 and many other microorganisms. Enzymes involved in this pathway were purified from cells of P. putida 77 and characterized. The first step, deimination of creatinine, is catalyzed by cytosine deaminase/creatinine deiminase. The following two steps, ring-opening of N-methylhydantoin and decarbamoylation of N-carbamoylsarcosine, are catalyzed by new enzymes, N-methylhydantoin amidohydrolase and N-carbamoylsarcosine amidohydrolase, respectively. The former requires ATP, Mg2+, and K+ for the hydrolysis and the reaction proceeds as follows: N-methylhydantoin + ATP + 2 H2O----N-carbamoylsarcosine + ADP + Pi. The latter catalyzes the following reaction; N-carbamoylsarcosine + H2O----sarcosine + NH3 + CO2. Sarcosine dehydrogenase was found to be the responsible enzyme for the oxidation of sarcosine to glycine in P. putida 77, but sarcosine oxidase was also found to be involved in this oxidation in several microorganisms. These enzymes were found to be useful tools for determination of creatinine.
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PMID:Microbial enzymes for creatinine assay: a review. 269 73