牛十二指肠蛋白酶（十二指肠酶）对多肽底物作用的比较研究。

Comparative study of the action of bovine duodenal proteinases (duodenases) on polypeptide substrates.

作者信息

Sokolova E A, Mirgorodskaya O A, Roepstorff P, Savelyeva N V, Zamolodchikova T S

机构信息

Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117871 Russia.

出版信息

Biochemistry (Mosc). 2001 Jan;66(1):62-7. doi: 10.1023/a:1002833729744.

DOI:10.1023/a:1002833729744

PMID:11240394

Abstract

A comparative study of substrate specificity of bovine duodenal proteinases--chymotrypsin-like duodenase (ChlD) and dual-specificity duodenase (dsD)--was carried out using oligopeptide substrates (human proinsulin, glucagon, melittin, angiotensinogen fragment 1-14). ChlD displayed mainly chymotrypsin-like properties towards these substrates, hydrolyzing peptide bonds carboxy-terminally to bulky aliphatic or aromatic residues. In melittin, ChlD additionally cleaved peptide bonds after Thr and Ser residues. Dual-specificity duodenase (dsD) significantly restricted its specificity to only trypsin-like or only chymotrypsin-like or displayed full activity, combining both specificities, depending on substrate. Both ChlD and dsD efficiently hydrolyzed a single peptide bond (Phe8--His9) in angiotensinogen fragment 1-14. The kinetic parameters of angiotensinogen fragment 1-14 cleavage by ChlD and dsD were determined (k(cat)/K(m) = 80,500 M(-1) x sec(-1) for ChlD and 103,000 M(-1) x sec(-1) for dsD).

摘要

利用寡肽底物（人胰岛素原、胰高血糖素、蜂毒肽、血管紧张素原片段1 - 14）对牛十二指肠蛋白酶——类胰凝乳蛋白酶十二指肠酶（ChlD）和双特异性十二指肠酶（dsD）的底物特异性进行了比较研究。ChlD对这些底物主要表现出类胰凝乳蛋白酶的特性，水解肽键的位置在大的脂肪族或芳香族残基的羧基末端。对于蜂毒肽，ChlD还能在苏氨酸和丝氨酸残基之后切割肽键。双特异性十二指肠酶（dsD）的特异性显著受限，仅表现出类胰蛋白酶特性或仅表现出类胰凝乳蛋白酶特性，或者根据底物不同同时展现出两种特异性的全部活性。ChlD和dsD都能有效水解血管紧张素原片段1 - 14中的单个肽键（苯丙氨酸8 - 组氨酸9）。测定了ChlD和dsD切割血管紧张素原片段1 - 14的动力学参数（ChlD的k(cat)/K(m) = 80,500 M(-1)×sec(-1)，dsD的k(cat)/K(m) = 103,000 M(-1)×sec(-1)）。