Abraham K I, Joshi P N
Biochim Biophys Acta. 1979 May 10;568(1):120-6. doi: 10.1016/0005-2744(79)90279-1.
The molecular weights of purified calotropain-FI and FII were determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and by filtration of Sephadex G-100. Activation of calotropain-FI and FII by different sulfhydryl activators was studied. The results obtained from inhibition studies by various enzyme-modifying reagents suggest the possible role of cysteine and histidine residues in the active site of both the enzymes. The free and total sulfhydryl contents of both the enzymes were determined by the use of 5-5'-dithio-bis-2-nitrobenzoic acid. Total amino acid compositions of both the enzymes were also determined. A comparative study of the esterase, amidase, milk-clotting and caseinolytic activities of calotropain-FI and FII are also presented.
通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和葡聚糖凝胶G-100过滤法测定了纯化的牛角瓜蛋白酶-FI和FII的分子量。研究了不同巯基激活剂对牛角瓜蛋白酶-FI和FII的激活作用。各种酶修饰试剂的抑制研究结果表明，半胱氨酸和组氨酸残基在这两种酶的活性位点中可能发挥作用。使用5-5'-二硫代双-2-硝基苯甲酸测定了这两种酶的游离巯基和总巯基含量。还测定了这两种酶的总氨基酸组成。本文还对牛角瓜蛋白酶-FI和FII的酯酶、酰胺酶、凝乳和酪蛋白分解活性进行了比较研究。
