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)

The enzymes that catalyse the salvage of purines in Entamoeba histolytica trophozoites have been surveyed. Adenine deaminase (EC 3.5.4.2), adenosine deaminase (EC 3.5.4.4), guanine deaminase (EC 3.5.4.3), adenine phosphoribosyltransferase (PRTase) (EC 2.4.2.7), xanthine PRTase (EC 2.4.2.22) and hypoxanthine PRTase (EC 2.4.2.8) were all detected in cell homogenates but only at low activities, whereas AMP deaminase (EC 3.5.4.6) and guanine PRTase (EC 2.4.2.8) were not found. Phosphorylases (EC 2.4.2.1) active in both anabolic and catabolic directions were present and all nucleosides tested were phosphorylated by kinases (EC 2.7.1.15, EC 2.7.1.20, EC 2.7.1.73). 3'-Nucleotidase (EC 3.1.3.6) and 5'-nucleotidase (EC 3.1.3.5) were found, the former being mainly particulate. Nucleotide interconversion enzymes (adenylosuccinate lyase, EC 4.3.2.2; adenylosuccinate synthetase, EC 6.3.4.4; IMP dehydrogenase, EC 1.2.1.14; GMP synthetase, EC 6.3.5.2 and GMP reductase, EC 1.6.6.8) were not detected. The results suggest that in E. histolytica the main route of nucleotide synthesis is from the individual bases through the actions of phosphorylases and kinases.
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PMID:Purine-metabolising enzymes in Entamoeba histolytica. 287 91

Cultured promastigote and isolated amastigote forms of Leishmania mexicana mexicana have been surveyed for the presence of enzymes involved in purine metabolism. Quantitative but not qualitative differences between the enzymes of two forms were discovered. There were found to be significant differences between the enzyme content of L. m. mexicana and that reported for L. donovani. Extracts of both parasite forms of L. m. mexicana were found to have higher levels of adenine deaminase (EC 3.5.4.2) and guanine deaminase (EC 3.5.4.3) than adenosine deaminase (EC 3.5.4.4). There appeared to be two distinct nucleosidases (EC 3.2.2.1), one active on nucleosides, the other on deoxynucleosides. Phosphorylase (EC 2.4.2.1) could be detected only in the catabolic direction. Nucleotidases were present, but were more active on 3' (EC 3.1.3.6)- than 5' (EC 3.1.3.5)-nucleotides. Phosphoribosyltransferase (EC 2.4.2.7,.8 and .22) and nucleoside kinase (EC 2.7.1.20) activities were detected in both forms. Nucleotide-interconverting enzymes were found to be present, with IMP dehydrogenase (EC 1.2.1.14) being the most active. Cell fractionation experiments revealed that, in the promastigote, enzyme separation within the parasite may play an important part in regulating cellular purine metabolism.
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PMID:Leishmania mexicana: purine-metabolizing enzymes of amastigotes and promastigotes. 298 37

Chemical and enzymatic procedures have been employed for the preparation of various phosphorylated derivatives of the acyclonucleoside 9-(1,3-dihydroxy-2-propoxymethyl)adenine, an analogue of the active antiviral agent 9-(1,3-dihydroxy-2-propoxymethyl)guanine (DHPG). In combination with the previously reported 2',3'-seco nucleosides and their phosphates and cyclic phosphates (Stolarski et al., Z. Naturforsch. 41c, 758-770, 1986), this made available a broad class of acyclonucleosides and nucleotides, the acyclic moieties of which are capable of mimicking the ribose and 2'-deoxyribose rings. The solution conformations of the foregoing were determined with the aid of 1H, 13C and 31P NMR, and compared with those of DHPG and 9-(hydroxyethoxymethyl)guanine (Acyclovir, ACV). Particular attention was devoted to conformations about C-O bonds in different acyclic fragments, which demonstrated well-defined differences between 2',3'-seco derivatives on the one hand (conformational "rigidity") and derivatives with DHP and AC acyclic chains on the other (rotation about the C(1')-O(4') bond). The overall results are in good general agreement with reported crystal structures, and are compared with those obtained by quantum mechanical calculations. The conformational features of the various compounds are also discussed in relation to their substrate and/or inhibitor properties in a number of enzyme systems, including adenosine deaminase, phosphodiesterases, nuclease P1,3'-nucleotidase and herpes virus type 1 thymidine kinase.
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PMID:Solution conformations of some acyclo nucleoside and nucleotide analogues of antiviral acyclonucleosides, and their substrate/inhibitor properties in several enzyme systems. 338 56