【摘要】 <正> 酶的催化作用起因于分子中某些部位氨基酸残基的特定空间结构,即“活性部位”的存在。使酶分子发生有限度的降解,观察它对酶活性的影响,乃至分离出具有酶活性的降解产物——“活性碎片”,这是研究酶的结构与功能的关系的方法之一。在这方面,胰蛋白酶特别引人注意,因为在一定条件下,无需外加蛋白酶,胰蛋白酶本身就能发生自溶作用;同时胰蛋白酶的高度的专一性对于确定肽链断裂的位置也是很有帮助的。更多还原

【Abstract】 1. Porcine trypsin obtained from pancreas residues subsequent to insulin re-moval underwent autolysis when subjected to chromatography and gave rise to new active forms of autolyzed products with intrachain split at bond Lys145-Ala146, Arg105-Val106.2. Incubation of 1% solutions of porcine trypsin either at pH 5.0 or at pH 9.1 induced autolysis to give active products involving one or two specific cleavage of bond Lys145-Ala146, Arg105-ValI06 or Lys131-Ser132, as well as inactive degraded products. No evidence was obtained that on autolysis of porcine trypsin, any active fragment with lower molecular size than the parent molecule was identified.3. The active forms of autolyzed products of porcine trypsin had almost the same specific activity as the intact enzyme when assayed against BAEE. They were of the same molecular size as the parent molecule. These findings indicated that the active forms of autolyzed products maintained the specific three-dimensional structure essential for the catalytic activity of the trypsin molecule.更多还原