Enzymes
UniProtKB help_outline | 1,888 proteins |
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- Name help_outline IMP Identifier CHEBI:58053 Charge -2 Formula C10H11N4O8P InChIKeyhelp_outline GRSZFWQUAKGDAV-KQYNXXCUSA-L SMILEShelp_outline O[C@@H]1[C@@H](COP([O-])([O-])=O)O[C@H]([C@@H]1O)n1cnc2c1nc[nH]c2=O 2D coordinates Mol file for the small molecule Search links Involved in 20 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H2O Identifier CHEBI:15377 (CAS: 7732-18-5) help_outline Charge 0 Formula H2O InChIKeyhelp_outline XLYOFNOQVPJJNP-UHFFFAOYSA-N SMILEShelp_outline [H]O[H] 2D coordinates Mol file for the small molecule Search links Involved in 6,264 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline inosine Identifier CHEBI:17596 (CAS: 58-63-9) help_outline Charge 0 Formula C10H12N4O5 InChIKeyhelp_outline UGQMRVRMYYASKQ-KQYNXXCUSA-N SMILEShelp_outline OC[C@H]1O[C@H]([C@H](O)[C@@H]1O)n1cnc2c(O)ncnc12 2D coordinates Mol file for the small molecule Search links Involved in 20 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline phosphate Identifier CHEBI:43474 Charge -2 Formula HO4P InChIKeyhelp_outline NBIIXXVUZAFLBC-UHFFFAOYSA-L SMILEShelp_outline OP([O-])([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 1,002 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
RHEA:27718 | RHEA:27719 | RHEA:27720 | RHEA:27721 | |
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More general form(s) of this reaction
Publications
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Purification and some properties of an IMP-specific 5'-nucleotidase from yeast.
Itoh R.
An IMP-hydrolysing enzyme was purified to homogeneity from yeast extract. It was a soluble protein with an apparent molecular mass of 220 kDa, with a subunit molecular mass of 55 kDa. It was highly specific for IMP, and there was virtually no detectable activity with the other purine and pyrimidin ... >> More
An IMP-hydrolysing enzyme was purified to homogeneity from yeast extract. It was a soluble protein with an apparent molecular mass of 220 kDa, with a subunit molecular mass of 55 kDa. It was highly specific for IMP, and there was virtually no detectable activity with the other purine and pyrimidine nucleotides tested, including AMP and dIMP. The enzyme had a pH optimum of 6.0-6.5. Its activity was absolutely dependent on bivalent metal salts: Mg2+ was most potent, followed by Co2+ and Mn2+. The velocity/substrate-concentration plot of the enzyme was slightly sigmoidal (h = 1.7) and the s0.5 was 0.4 mM. ATP stimulated the enzyme by decreasing both h and s0.5. Diadenosine tetraphosphate stimulated the enzyme as effectively as ATP. Although the properties of the enzyme are similar to those of the IMP/GMP 5'-nucleotidase identified in various animals [Itoh (1993) Comp. Biochem. Physiol. 105B, 13-19], the substrate specificity of the former was much more strict than the latter. << Less
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The yeast ISN1 (YOR155c) gene encodes a new type of IMP-specific 5'-nucleotidase.
Itoh R., Saint-Marc C., Chaignepain S., Katahira R., Schmitter J.-M., Daignan-Fornier B.
<h4>Background</h4>The purine salvage enzyme inosine 5'-monophosphate (IMP)-specific 5'-nucleotidase catalyzes degradation of IMP to inosine. Although this enzymatic activity has been purified and characterized in Saccharomyces cerevisiae, the gene encoding IMP 5'-nucleotidase had not been identif ... >> More
<h4>Background</h4>The purine salvage enzyme inosine 5'-monophosphate (IMP)-specific 5'-nucleotidase catalyzes degradation of IMP to inosine. Although this enzymatic activity has been purified and characterized in Saccharomyces cerevisiae, the gene encoding IMP 5'-nucleotidase had not been identified.<h4>Results</h4>Mass spectrometry analysis of several peptides of this enzyme purified from yeast allowed identification of the corresponding gene as YOR155c, an open reading frame of unknown function, renamed ISN1. The deduced Isn1p sequence was clearly not homologous to 5'-nucleotidases from other species. However, significant similarities to Isn1p were found in proteins of unknown function from Neurospora crassa, Plasmodium falciparum and several yeast species. Knock-out of ISN1 resulted in the total loss of IMP-specific 5'-nucleotidase activity, thus confirming that the ISN1 gene indeed encodes the enzymatic activity purified from yeast. In vivo studies revealed that, when IMP is overproduced through constitutive activation of the IMP de novo synthesis pathway, ISN1 is required for excretion of inosine and hypoxanthine in the medium.<h4>Conclusion</h4>We have identified a new yeast gene, ISN1 (YOR155c), as encoding IMP-specific 5'-nucleotidase activity. The ISN1 gene defines a new type of 5'-nucleotidase which was demonstrated to be functional in vivo. << Less