Co+2-Substituted Acylamino Acid Amido Hydrolase from Aspergillus oryzae

Abstract

Abstract Dedicated to Prof. H. Zahn on the Ocassion of His 65th Birthday Zn+2/Co+2 Exchange, Microbial Acylamino Acid Amido Hydrolase, Aspergillus oryzae, Kinetic Properties The inactivation of the Zn+2 metallo enzyme acylamino acid amido hydrolase from Aspergillus oryzae by ethylendiamine-tetraacetate (EDTA) and nitrilotriacetate (NTA) and the effects of Phe and His on this process were studied. Reactivation of the enzyme by Zn+2-or Co+2-NTA buffer revealed a dissociation constant for the Zn+2-enzyme of 10~10 M and for the Co+2-enzyme of 10-7-5 m. The kinetic properties of the Zn+2 and Co+2 enzyme were compared for a series of substrates. Substitution of Co+2 for Zn+2 reduces substrate specificity of the enzyme.