[Isolation and properties of the acid carboxypeptidase of Aspergillus oryzae].

Caboxypeptidase with pH optimum 4--5 for peptide substrates is isolated from "oryzine", the enzyme mixture produced by Aspergillus oryzae, by means of successive salt fractionation, Sephadex G-75 gel filtration, chromatography on amberlite IRC-50, hydroxylapatite, DEAE-cellulose and polyacrylamide gel electrophoresis. Its molecular weight, as determined by means of polyacrylamide gel electrophoresis in the presence of sodium dolecylsulphate, was found to be 37 000. The enzyme has a broad substrate specificity and does not possess dipeptidase and esterase activities. Acid carboxypeptidase from Asp. oryzae is not a metalloenzyme, it is inactivated by specific inhibitors of serine proteases and by compounds blocking SH-groups. The enzyme is suggested to contain functionally important serine and cysteine residues and to be acid carboxipeptidase.