Esterases belong to the hydrolase family and are present in variety of species. Esterase (EST) from pseudomonas putida IFO12996 hydrolyaes DL-beta-acetythioisobutyrate (DL-MATI) to produce D-beta-acetythioisobutric acid (DAT), serving as a key intermediate for the synthesis of angiotensin converting enzyme inhibitors. The crystal structure of EST has been investigated by x-ray diffraction to a resolution of 1.6A. It reveals that EST is a member of the alpha/beta hydrolase fold and contains a catalytic triad of Ser97,Asp227, and His256. The active site is located about in the middle of the ESTat the end of a pocket. EST can hydrolase the methyl ester group without affecting the aetylthiol ester moiety in DL-MATI. This confirms varied substrate specifications but not its reactivities.
