Aspartate racemase
In enzymology, an aspartate racemase () is an enzyme that catalyzes the following chemical reaction: L-aspartate D-aspartate This enzyme belongs to the family of isomerases, specifically those racemases and epimerases acting on amino acids and amino acid derivatives, including glutamate racemase, proline racemase, and diaminopimelate epimerase. The systematic name of this enzyme class is aspartate racemase. Other names in common use include D-aspartate racemase, and McyF. Discovery Aspartate racemase was first discovered in the gram-positive bacteria Streptococcus faecalis by Lamont et al. in 1972. It was then determined that aspartate racemase also racemizes L-alanine around half as quickly as it does L-aspartate, but does not show racemase activity in the presence of L-glutamate. Structure The crystallographic structure of bacterial aspartate racemase has been solved in Pyrococcus horikoshii OT3, Escherichia coli, Microcystis aeruginosa, and Picrophilus torridus DSM 9790. Homodimer In most bacteria for which the structure is known, aspartate racemase exists as a homodimer, where each subunit has a molecular weight of approximately 25 kDa. The complex consists primarily of alpha helices, and additionally features a Rossmann fold in the center of the dimer. The catalytic pocket lies at the cleft formed by the intersection of the two domains. A citrate