ISOLATION OF CARBOXYPEPTIDASE Y BY AFFINITY CHROMATOGRAPHY

Carboxypeptidase Y from bakers'' yeast was purified in high yields by affinity chromatography. The affinity gel was prepared by coupling the specific inhibitor p-aminobenzylsuccinic acid via an azo linkage to Sepharose-glycyl-tyrosine. This affinity gel was able to bind carboxypeptidase Y specifically and quantitatively from a crude yeast autolysate. The isolated enzyme appeared homogeneous by gel electrophoresis and ultracentrifugation, while isoelectric focusing revealed the presence of 2 components with isoelectric points of pH 3.56 and 3.66, respectively. Small differences in amino acid composition and enzymatic properties between the enzyme from danish yeast and the corresponding enzyme isolated from Fleichmann yeast suggested the existence of more than 1 form of this enzyme.