从成年和幼年红大麻哈鱼（Oncorhynchus keta）中部分纯化胃蛋白酶。氯化钠对蛋白水解活性的影响。

Partial purification of pepsins from adult and juvenile salmon fish Oncorhynchus keta. Effect of NaCl on proteolytic activities.

Sánchez-Chiang L, Cisternas E, Ponce O

Departamento de Biología Molecular, Facultad de Ciencias Biológicas y de Recursos Naturales, Universidad de Concepción, Chile.

Comp Biochem Physiol B. 1987;87(4):793-7. doi: 10.1016/0305-0491(87)90390-7.

Abstract

Two pepsins, designated Pepsin I and Pepsin II, were isolated and partially characterized from the stomach of the adult stage salmon Oncorhynchus keta. This stage is developed in a marine environment. 2. One pepsin, designated Pepsin II, was isolated from the stomach of the juvenile stage salmon Oncorhynchus keta. This stage is developed in an estuarine environment. 3. The enzymes were partially purified by ammonium sulfate precipitation, ion exchange chromatography and gel filtration. 4. Pepsins I and II from adults and Pepsin II from juvenile showed proteolytic activity on acid-denatured hemoglobin with a pH optimum of 3. 5. The mol. wt determined by gel filtration on Sephadex G-100 of Pepsin I from juvenile species was found to be 32,000 whereas a value of 27,000 was determined for Pepsin II from juvenile and adult fish. 6. In contrast with Pepsin II, Pepsin I was activated by NaCl. It is suggested that the appearance of NaCl-activated pepsin would represent and adaptive response of the organism to the change from a low to a high salinity environment.

摘要

从成年期鲑鱼（大麻哈鱼）的胃中分离出两种胃蛋白酶，分别命名为胃蛋白酶I和胃蛋白酶II，并对其进行了部分特性鉴定。成年期鲑鱼在海洋环境中发育。2. 从幼年期鲑鱼（大麻哈鱼）的胃中分离出一种胃蛋白酶，命名为胃蛋白酶II。幼年期鲑鱼在河口环境中发育。3. 通过硫酸铵沉淀、离子交换色谱和凝胶过滤对这些酶进行了部分纯化。4. 成年鲑鱼的胃蛋白酶I和II以及幼年鲑鱼的胃蛋白酶II对酸变性血红蛋白具有蛋白水解活性，最适pH为3。5. 通过在Sephadex G - 100上进行凝胶过滤测定，幼年鲑鱼的胃蛋白酶I的分子量为32,000，而幼年和成年鱼的胃蛋白酶II的分子量为27,000。6. 与胃蛋白酶II不同，胃蛋白酶I被NaCl激活。有人认为，NaCl激活的胃蛋白酶的出现代表了生物体对从低盐度环境到高盐度环境变化的一种适应性反应。