Epimerase and racemase

Epimerases and racemases are isomerase enzymes that catalyze the inversion of stereochemistry in biological molecules.[1] 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,[2] 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

  • Galactose epimerase deficiency

References

  1. ^ 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.
  2. ^ "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)
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Isomerases: Epimerase and racemases (EC 5.1)
5.1.1: Amino acids
  • Amino-acid racemase: Phenylalanine racemase (ATP-hydrolysing)
  • Serine racemase
5.1.2: Hydroxy acids
  • Mandelate racemase
  • Isocitrate epimerase
5.1.3: Carbohydrates5.1.99: Other


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