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- Name help_outline isoguanine Identifier CHEBI:62462 (CAS: 3373-53-3) help_outline Charge 0 Formula C5H5N5O InChIKeyhelp_outline DRAVOWXCEBXPTN-UHFFFAOYSA-N SMILEShelp_outline Nc1nc(=O)[nH]c2nc[nH]c12 2D coordinates Mol file for the small molecule Search links Involved in 1 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 H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,521 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline xanthine Identifier CHEBI:17712 (CAS: 69-89-6) help_outline Charge 0 Formula C5H4N4O2 InChIKeyhelp_outline LRFVTYWOQMYALW-UHFFFAOYSA-N SMILEShelp_outline O=c1[nH]c2[nH]cnc2c(=O)[nH]1 2D coordinates Mol file for the small molecule Search links Involved in 18 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline NH4+ Identifier CHEBI:28938 (CAS: 14798-03-9) help_outline Charge 1 Formula H4N InChIKeyhelp_outline QGZKDVFQNNGYKY-UHFFFAOYSA-O SMILEShelp_outline [H][N+]([H])([H])[H] 2D coordinates Mol file for the small molecule Search links Involved in 529 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:47720 | RHEA:47721 | RHEA:47722 | RHEA:47723 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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Rescue of the orphan enzyme isoguanine deaminase.
Hitchcock D.S., Fedorov A.A., Fedorov E.V., Dangott L.J., Almo S.C., Raushel F.M.
Cytosine deaminase (CDA) from Escherichia coli was shown to catalyze the deamination of isoguanine (2-oxoadenine) to xanthine. Isoguanine is an oxidation product of adenine in DNA that is mutagenic to the cell. The isoguanine deaminase activity in E. coli was partially purified by ammonium sulfate ... >> More
Cytosine deaminase (CDA) from Escherichia coli was shown to catalyze the deamination of isoguanine (2-oxoadenine) to xanthine. Isoguanine is an oxidation product of adenine in DNA that is mutagenic to the cell. The isoguanine deaminase activity in E. coli was partially purified by ammonium sulfate fractionation, gel filtration, and anion exchange chromatography. The active protein was identified by peptide mass fingerprint analysis as cytosine deaminase. The kinetic constants for the deamination of isoguanine at pH 7.7 are as follows: k(cat) = 49 s(-1), K(m) = 72 μM, and k(cat)/K(m) = 6.7 × 10(5) M(-1) s(-1). The kinetic constants for the deamination of cytosine are as follows: k(cat) = 45 s(-1), K(m) = 302 μM, and k(cat)/K(m) = 1.5 × 10(5) M(-1) s(-1). Under these reaction conditions, isoguanine is the better substrate for cytosine deaminase. The three-dimensional structure of CDA was determined with isoguanine in the active site. << Less