新鮮鯖魚(Scomber australasicus)內臟經酒精處理及水洗後，製成丙酮粉，再以去離子水由丙酮粉抽取酵素，然後經30-70%硫銨分劃，Ultrogel AcA 44膠濾及DEAE-Sephadex A-50管柱層析後得兩種蛋白酶，分別稱為A及B，在不連續膠體電泳上A僅呈一絛電泳帶(band)，為純化之蛋白酶， B為兩條電泳帶。依照基質特異性推測，A及B皆為胰蛋白酶。胰蛋白酶A及B水解TAME的最適pH分別在9.0及7.6左右，水解酪蛋白最適溫度分別在45℃及55℃。A及B在50℃以下皆安定，起過80℃均失活。在中性及微鹼性都安定。以SDS-polyacrylamide膠體電泳測定， A分子量為29,200。蛋白酶A稍受金屬離于Na+、Co2+之活化及受 Hg2+之抑制，蛋白酶B稍受Na+ 、EDTA活化及受Ca2+、Hg2+之抑制。以TAME為基質，A之Km為9.1 x l0-4 M, Vmax為5.6 x l0 5units/mole enzyme/min。 Proteinases in acetone powder of mackerel viscera were extracted with deion-ized water and purified by 30-70% ammonium sulfate fractionation, Ultrogel AcA. 44 gel fltration, and DEAE-Sephadex A-50 ion exchange chromatography.Two proteinase peaks having caseinolytic activity, named A and B respectively,were obtained from the DEAE-Sephadex A-50 elution. Proteinase A was homogenous showing a single band on disc-polyacrylamide gel electrophoresis, while proteinase B yieded two bands. Both proteinase A and B were trypsin-like enzymes on the basis of authentic substrate specificity.The optimum pH of mackerel visceral proteinase A and B for hydrolysis of TAME was found to be 9.0 and 7.6 respectively. The optimum temperature of A and B for hydrolysis of casien was 45℃ and 55℃ respectively. Both proteinases were stable below 50℃ in neutral and slightly alkaline pH. Activity disappeared above 80℃, or at acidic pH. Molecular weight of the proteinase A was determined to be 29,200 by SDS-polyacrylamide gel electroohoresis. The activity of proteinase A was slightly activated by Na+ and Co2+, and was inhibited by Hg2+. Proteinase B was slightly activited by Na+ and EDTA, and was inhibited by Ca2+ and Hg2+. The Michaelis constant (Km), and maximal velocity (Vmax) of proteinase A were found to be 9.1 x 10-4M and 5.6 x 10 5 unit/mole enzyme/min respectively
