We have treated a patient with refractory T-cell acute lymphoblastic leukemia with 2'-deoxycoformycin, a potent inhibitor of the enzyme adenosine deaminase. Inhibition of adenosine deaminase activity resulted in (1) an abrupt rise in plasma deoxyadenosine, but not adenosine, concentrations; (2) accumulation of deoxyadenosine triphosphate by lymphoblasts; (3) inhibition of the enzyme S-adenoylho...

The analysis of progress curves using the integrated rate equation was applied to the adenosine deaminase-catalyzed conversion of adenosine to inosine. Adenosine deaminase was purified from human red blood cells of phenotypes ADA 1, ADA 2, and ADA 2-1. For all three types, no measurable product inhibition by inosine was observed. These results do not confirm the hypothesis that inosine accumula...

In 1928, Schmidt (1) first described the presence of 5’-adenylic acid deaminase in muscle. He succeeded in separating this enzyme from adenosine deaminase and in isolating inosinic acid and ammonia as products of the reaction. He also reported that it specifically deaminated 5’-adenylic acid. In 1947, Kalckar (2) described two methods for the preparation of this enzyme and introduced a spectrop...

The regulation of platelet AMP deaminase activity by ATP, GTP and phosphate was studied in human platelets in situ, and in vitro after partial purification. In intact platelets, a similar 50% decrease in cytosolic ATP was induced by either glucose starvation or treatment with H2O2. During starvation, AMP deaminase was in the inhibited state, as ATP consumption was mostly balanced by the accumul...

Herpes simplex virus type 1 induces deoxycytidine deaminase (cytidine/deoxycytidine aminohydrolase, EC 3.5.4.5) activity when it lytically infects a number of mammalian cell lines. The deaminase activity is induced in a mouse cell line that is deficient in this enzyme. The induction of the enzyme in this mutant cell line does not occur in the presence of actinomycin D and the induced enzyme is ...

The present study was carried out with the following objectives: (1) to isolate the endophytic bacilli strains from the leaves of mangrove plant Avicennia marina, (2) to screen the potential strains for the production of adenosine deaminase, (3) to statistically optimize the factors that influence the enzyme activity in the potent strain, and (4) to identify the potent strain using 16S rRNA seq...

In adipocytes, adenylate cyclase is positively regulated by beta-adrenergic agents and negatively regulated by adenosine. Incubation of adipocytes with adenosine deaminase relieves the inhibition of adenylate cyclase by destroying the adenosine that the cells release into the medium. When adipocytes are incubated with adenosine deaminase and the beta-adrenergic agent isoproterenol, most of thei...

Erythrocytes from 11 patients with presumptive diagnoses of transient erythroblastopenia of childhood were evaluated retrospectively (six) or prospectively (five) for a possible relationship between erythrocyte adenosine 5'-monophosphate aminohydrolase, adenylic acid deaminase (AMP deaminase) activity and intracellular concentrations of adenine nucleotides. Older red blood cell (RBC) cohorts in...

Traditionally, Mycobacterium tuberculosis or granulomas have to be evidenced in the pleural cavity in order to establish a diagnosis of tuberculous pleuritis. In recent years, adenosine deaminase has aided tremendously in the diagnosis of tuberculous pleural effusion, often obviating the need for microbiologic or histologic verification of the diagnosis. However, the fact that the sensitivity o...

5-Fluoro-2'-deoxycytidine (FdCyd) is a potent inhibitor of growth of tissue culture cells. The major cytotoxic event appears to be inhibition of thymidylate synthetase as evidenced by reversal of the cytotoxicity with thymidine but not deoxycytidine and by the effect of FdCyd on nucleotide pools, which is characteristic of specific inhibition of this enzyme. The metabolism of FdCyd was establis...