PMID:21604715
| Citation |
Hitchcock, DS, Fedorov, AA, Fedorov, EV, Dangott, LJ, Almo, SC and Raushel, FM (2011) Rescue of the orphan enzyme isoguanine deaminase. Biochemistry 50:5555-7 |
|---|---|
| Abstract |
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. |
| Links |
PubMed PMC3138507 Online version:10.1021/bi200680y |
| Keywords |
Catalysis; Cytosine/chemistry; Cytosine/metabolism; Deamination; Escherichia coli Proteins/chemistry; Escherichia coli Proteins/metabolism; Guanine/analogs & derivatives; Guanine/chemistry; Guanine/metabolism; Guanine Deaminase/chemistry; Guanine Deaminase/metabolism; Kinetics; Substrate Specificity |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
See also
References
See Help:References for how to manage references in EcoliWiki.