PMID:10858304
| Citation |
Rishavy, MA and Cleland, WW (2000) 13C and (15)N kinetic isotope effects on the reaction of aspartate aminotransferase and the tyrosine-225 to phenylalanine mutant. Biochemistry 39:7546-51 |
|---|---|
| Abstract |
Heavy atom isotope effects at C-2, C-3, and the amino nitrogen of aspartate were determined for the reaction of porcine heart cytosolic aspartate aminotransferase and the tyrosine-225 to phenylalanine mutant of Escherichia coli aspartate aminotransferase. The effects of deuteration at C-2 of aspartate and of D(2)O on the observed heavy atom isotope effects were determined. The multiple isotope effects support the contribution of C(alpha)-H cleavage, ketimine hydrolysis, and oxaloacetate dissociation to the rate limitation with the wild-type enzyme. The existence of a quinonoid intermediate could not be determined due to the kinetic complexity of the enzyme. For the tyrosine-225 to phenylalanine mutant, we are able to conclude that ketimine hydrolysis is the major rate-determining step. |
| Links | |
| Keywords |
Amino Acid Substitution; Aspartate Aminotransferases/chemistry; Carbon Isotopes; Nitrogen Isotopes; Phenylalanine/chemistry; Tyrosine/chemistry |
| 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)
References
See Help:References for how to manage references in EcoliWiki.