Epimerases and racemases are isomerase enzymes that catalyze the inversion of stereochemistry in biological molecules. Racemases catalyze the stereochemical inversion around the asymmetric carbon atom in a substrate having only one center of asymmetry. Epimerases catalyze the stereochemical inversion of the configuration about an asymmetric carbon atom in a substrate having more than one center of asymmetry, thus interconverting epimers.
Human epimerases include methylmalonyl-CoA epimerase, involved in the metabolic breakdown of the amino acids alanine, isoleucine, methionine and valine, and UDP-glucose 4-epimerase, which is used in the final step of galactose metabolism - catalyzing the reversible conversion of UDP-galactose to UDP-glucose.
See also
References
- Tanner, ME. (2002). "Understanding nature's strategies for enzyme-catalyzed racemization and epimerization". Acc. Chem. Res. 35 (4): 237–246. doi:10.1021/ar000056y. PMID 11955052.
- "Isomerase | enzyme | Britannica".
External links
- http://medical-dictionary.thefreedictionary.com/racemase
- http://medical-dictionary.thefreedictionary.com/epimerase
- Entry+Term+Epimerases at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
| Isomerases: Epimerase and racemases (EC 5.1) | |
|---|---|
| 5.1.1: Amino acids | |
| 5.1.2: Hydroxy acids | |
| 5.1.3: Carbohydrates | |
| 5.1.99: Other | |
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