Studies On Dual-enzyme Catalysed Deracemization Of α-Amino Acids

Enantiomerically pure amino acids are important products for the chemical industry as special intermediates for chiral compounds produced by pharmaceutical and agrochemical companies, as enantiomerically pure chiral products often require lower doses and have improved efficiency over their racemic counterparts. Having enantiomerically pure products also means that there is no risk of the other enantiomer of the compound having an unwanted effect, as happened the case of the thalidomide drug, where the (S)-form of the drug had a teratogenic effect that the (R)-form did not.In this article, we prepared enantiomerically pure L-amino acids from the a-racemic chiral Amino Acids by the method of dual enzyme biocatalyst. Amino acid oxidases (AAOs) are enantioselective flavoenzymes that catalyse the oxidation of amino acids into imino acids, which spontaneously hydrolyse in water to form keto-acids and Oxygen, the terminal redox acceptor, reoxidizes the reduced FAD cofactor to give hydrogen peroxide. Amino transferases (ATs) catalyse the reversible transfer of an amino to a keto group in a reaction between an amino acid (as an amino donor) and a keto acid (as amino acceptor). Many bacterial ATs accept a wide array of keto acids as amino acceptors and are useful as biocatalysts in the preparation of AAs.This experiment is divided into three aspects:1. We chose DL-Met as a reaction substrate, and developed an enzymatic method for the deracemization of DL-Met by adding an appropriate amino donor.2. We discussed the mechanism of the deracemization of DL-Met by a series of work.3. The commercially availa Monosodium glutamate (abbreviate for L-Glu) was used as an amino donor, we studied the substrate specificity and the difference in reactivity when the substituting groups changes.