야생 연어 알중의 carboxypeptidase A를 CM-cellulose, $(NH_4)_2SO_4$ 분별침전, DEAE-cellulose column chromatography 및 sephadex G-75 겔 여과로 정제하여, 그 특성을 조사하였다. 활성분획 A는 기질 bovine hemoglobin 및 hippuryl-L-phenylalanine에 대하여 활성을 보였다. 이 효소의 분자량은 44,000 dalton이었으며, 18종의 서로 다른 아미노산으로 구성되어 있는 단량체였다. 최적 pH는 4.5, 최적 온도는 $60^{circ}C$ 였고, pH 2.5~5.5, $20^{circ}C{sim}60^{circ}C$에서 30분간 안정하였다. 이 효소는 glycyl-L-phenylalanine의 펩티드 결합을 분해시키는 특이성을 보였으며, $K_m$ 값은 0.29 mM이었다. 효소활성은 $Zn^{2+}$, $Fe^{3+}$, 및 L-cysteine에 의하여 억제되었으며, L-cysteine은 경쟁적 억제인자였고, 그 $K_i$ 값은 1.2 mM이었다.
The enzymic properties of carboxypeptidase A in the eggs of salmon (Salmo salar) were investigated by purification with CM-cellulose, ammonium sulfate fractionation, DEAE-cellulose, and sephadex G-75 gel filtration. The fraction A showed its activity toward substrate such as bovine hemoglobin and hippuryl-L-phenylalanine. The molecular weight of this enzyme was determined to be 44,000 daltons by SDS-PAG electrophoresis and the enzyme was monomeric protein composed of 18 different amino acids. Optimum pH was 4.5, optimum temperature was $60^{circ}C$, and the enzyme was stable at pH 2.5-5.5 and $20^{circ}C-60^{circ}C$. This enzyme showed substrate specificity hydrolyzing the peptide bond of glycyl-L-phenylalanine. Its $K_m$ value was 0.29 mmol and the enzyme was inhibited by $Zn^{2+}$, $Fe^{3+}$, and L-cysteine. The L-cysteine was found to be competitive inhibitor, and its $K_i$ value was determined to be 1.2 mmol by Dixon plot.
