5 -carboxamide, adenosine 5’-phosphate

Pyrazomycin. Pyrazomycin (11), 3-(l-p-D-ribofuranosyl)-4-hydroxypyrazole 5-carboxamide, is isolated from S. Candidas (1—4,9,10). The incorporation of [2-13C]acetate and [1- and U-14C]glutamate into the four contiguous carbons of pyrazomycin has been reported (11,12). Pyrazomycin 5 -phosphate inhibits orotidylic acid decarboxylase. Pyrazomycin inhibits adenosine phosphorylation and decreases the incorporation of deoxyuridine into DNA of Novikoff hepatoma cells in culture. It also inhibits the growth of tumor cells and the cytopathic effects of vaccinia, herpes simplex, vesicular stomatitis, Newcasde disease, measles, Sindbis, polio, hepatitis A, and coxsackie viruses (13,14). The inhibitory action of (11) on viral multiplication is reversed by uridine. 

Inosine can be converted directly to inosinate by inosine kinase. This enzyme has been shown to exist in human cells, but at a low level (P2). It undoubtedly does not play a major role. Inosine phosphorylase cleaves inosine to hypoxanthine and ribose I-phosphate (Kl). Inosine is formed by the deamination of adenosine catalyzed by adenosine deaminase, an enzyme found in varying concentrations in essentially all normal mammalian cells examined. Studies with an inhibitor of adenosine deaminase, ribosyl-4-amino-5-imidazole carboxamide, on several strains of Escherichia coli revealed a major role for the enzyme. In cells with a block in purine synthesis a condition of guanine deprivation occurred after growth with adenine as purine source, and there was a derepression of the enzymes that convert IMP to XMP and XMP to GMP (K17). 

Adenosine triphosphate disodium, A-39 Adenosine triphosphate, A-39 Adenosine 5 -triphosphoric acid, A-39 Adenosine 5 -uridine 5 -phosphate, A-40 Adenosine 5 -[4-(fluorosulfonyl)benzoate], F-17 Adenosine, A-31 e-Adenosine, R-110 a-Adenosine, A-31 Adenosine-5 -carboxamide, A-41 Adenosine-5 -carboxylic acid, A-41 Adenosine-5 -diphosphoric acid, A-33 Adenosine-5 -N-ethyluronamide, A-41 Adenosine-5 -phosphoric acid, A-44 Adenosine-2 -phosphoric acid, A-45 Adenosine-5 -uronic acid, A-41 S -Adenosylhomocysteine, A-42 S -Adenosylmethionine, A-26 Adenosylsuccinic acid, A-43 Adenylic acid a, A-45... 

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