Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.4.4 (adenosine deaminase)
 5,136 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Coformycin, which is an inhibitor of adenosine deaminase, significantly inhibited in vitro blastogenic responses of human lymphocytes to both phytohaemagglutinin (PHA) and pokeweed mitogen (PWM), whereas blastogenic responses to bacterial lipopolysaccharide (LPS) were rather enhanced by the addition of coformycin. Blastogenic responses of lymphocytes to PHA and PWM were markedly suppressed by the addition of adenosine, which is a substrate of adenosine deaminase. Allopurinol, which is an inhibitor of xanthine oxidase, inhibited blastogenic responses of human lymphocytes to PHA, PWM, and bacterial LPS. Inosine (a substrate of purine nucleoside phosphorylase) and hypoxanthine (a substrate of xanthine oxidase) showed no or only a small effect on blastogenic responses of human lymphocytes. These results suggest that adenosine deaminase activity is associated with the T-cell response but not with the B-cell response and that the impaired T-cell response in adenosine deaminase deficiency is the result of intracellular retention of adenosine in T cells. The results also suggest that purine nucleoside phosphorylase or xanthine oxidase activity is associated with both T- and B-cell responses.
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PMID:Purine metabolic enzymes in lymphocytes. IV. Effects of enzyme inhibitors and enzyme substrates on the blastogenic responses of human lymphocytes. 392 75

The effects on ATP breakdown of some modulators of adenosine transport or metabolism were studied in the rat colon muscularis mucosae, a tissue which contracts to ATP and is thought to contain P2Y1 receptors. The compounds tested were the xanthine oxidase inhibitor allopurinol, the adenosine deaminase inhibitor erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA) and the adenosine uptake blocker S-(4-nitrobenzyl)-6-thioinosine (NBTI). The degradation of adenosine 5'-triphosphate (ATP) (100 microM) and the appearance of metabolites was followed by high pressure liquid chromatography during incubation of isolated tissue preparations alone or in the presence of the drugs, following preincubation with the drugs for 1 h. In the absence of drugs ATP was rapidly degraded by the rat colon muscularis mucosae with a half-life of 6.1 +/- 0.7 min, the major breakdown product being inosine rather than adenosine. Allopurinol (1 microM) and NBTI (10 microM) had no effect on the rate of breakdown of ATP or on the pattern of metabolites produced. EHNA (1 or 10 microM) also had no effect on the half-life of ATP, but in the presence of EHNA (1 microM) the rate of production of inosine was significantly reduced and some adenosine was detected, while in the presence of 10 microm EHNA the production of inosine was abolished and adenosine became the final breakdown product. These results indicate that allopurinol (1 microM) and NBTI (10 microM) have no detectable effect on extracellular purine metabolism in this tissue, and that the build-up of adenosine produced by treatment with EHNA does not have a feedback effect on ATP breakdown.
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PMID:Effects of allopurinol, erythro-9-(2-hydroxy-3-nonyl)adenine and S-(4-nitrobenzyl)-6-thioinosine on the degradation of adenosine 5'-triphosphate in the rat colon muscularis mucosae. 1058 73

This study examined the cytoprotective mechanisms of a combination of ischemic preconditioning (IPC) and allopurinol against liver injury caused by ischemia/reperfusion (I/R). Allopurinol (50mg/kg) was intraperitoneally administered 18 and 1h before sustained ischemia. A rat liver was preconditioned by 10 min of ischemia, followed by 10 min of reperfusion, and then subjected to 90 min of ischemia, followed by 5h of reperfusion. Rats were pretreated with adenosine deaminase (ADA), 3,7-dimethyl-1-[2-propargyl]-xanthine (DMPX), and N-nitro-l-arginine methyl ester (l-NAME) before IPC. Hepatic nitrite and nitrate and eNOS protein expression levels were increased by the combination of IPC and allopurinol. This increase was attenuated by ADA, DMPX, and l-NAME. I/R induced an increase in alanine aminotransferase activity, whereas it decreased the hepatic glutathione level. A combination of IPC and allopurinol attenuated these changes, which were abolished by ADA, DMPX, and l-NAME. The increase in the liver wet weight-to-dry weight ratio after I/R was attenuated by the combination of IPC and allopurinol. In contrast, hepatic bile flow was decreased after I/R, which was attenuated by the combination of IPC and allopurinol. These changes were restored by l-NAME. I/R induced a decrease in the level of mitochondrial dehydrogenase, whereas it increased mitochondrial swelling. A combination of IPC and allopurinol attenuated these changes, which were restored by ADA, DMPX, and l-NAME. Our findings suggest that a combination of IPC and allopurinol reduces post-ischemic hepatic injury by enhancing NO generation.
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PMID:A combination of ischemic preconditioning and allopurinol protects against ischemic injury through a nitric oxide-dependent mechanism. 2211 49