Epimerases and racemases are
isomerase enzymes that catalyze the inversion of
stereochemistry
Stereochemistry, a subdiscipline of chemistry, involves the study of the relative spatial arrangement of atoms that form the structure of molecules and their manipulation. The study of stereochemistry focuses on the relationships between stereois ...
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
Methylmalonyl CoA epimerase (, ''methylmalonyl-CoA racemase'', ''methylmalonyl coenzyme A racemase'', ''DL-methylmalonyl-CoA racemase'', ''2-methyl-3-oxopropanoyl-CoA 2-epimerase ncorrect') is an enzyme involved in fatty acid catabolism that is ...
, involved in the metabolic breakdown of the amino acids
alanine,
isoleucine
Isoleucine (symbol Ile or I) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH form under biological conditions), an α-carboxylic acid group (which is in the deprot ...
,
methionine
Methionine (symbol Met or M) () is an essential amino acid in humans. As the precursor of other amino acids such as cysteine and taurine, versatile compounds such as SAM-e, and the important antioxidant glutathione, methionine plays a critical ro ...
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
*
Galactose epimerase deficiency
References
External links
* http://medical-dictionary.thefreedictionary.com/racemase
* http://medical-dictionary.thefreedictionary.com/epimerase
*
Isomerases
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