Kinetics of a Chitinase from a Prawn, Penaeus japonicus
Kinetics of a Chitinase from a Prawn, Penaeus japonicus
复制标题
日本对虾几丁质酶的动力学
DOI：
10.1080/00021369.1990.10870347
复制
发表时间：
1990
期刊：
影响因子：
--
通讯作者：
C. Shimizu
中科院分区：
文献类型：
--
作者：
D. Koga;K. Mizuki;A. Ide;M. Kono;T. Matsui;C. Shimizu
以n -乙酰壳寡糖（GlcNAcn, n = 2 ~ 6）、对硝基苯基n -乙酰壳寡糖（pNp-GlcNAcn, n = 1 ~ 5）和胶体几丁质为底物，对日本对虾肝脏中纯化的几丁质酶（EC 3.2.1.14）进行了动力学分析。该酶通过两种途径将GlcNAc4水解为2分子GlcNAc2，将GlcNAc5水解为GlcNAc2 + GlcNAc3，将GlcNAc6水解为GlcNAc2 + GlcNAc4(87%)，将GlcNAc3水解为2分子（13%）。GlcNAc2和GlcNAc3均未被水解。GlcNAc4、GlcNAc5和GlcNAc6的Km和kcat分别为0.249 mm和3.38 sec−1、0.018 mm和2.67 sec−1和0.005 mm和2.72 sec−1。对硝基苯n -乙酰基壳寡糖的裂解模式与相应的n -乙酰基壳寡糖不同。该酶水解胶体几丁质，主要产生GlcNAc2和微量GlcNAc3。Allosamidin竞争性抑制对虾几丁质酶，Ki值为0.1 μm， IC50值为0.14 μm。这些结果表明p…
Kinetic analysis was done on a chitinase (EC 3.2.1.14) purified from the liver of a prawn, Penaeus japonicus, using N-acetylchitooligosaccharides (GlcNAcn, n = 2 to 6), p-nitrophenyl N-acetylchitooligosaccharides (pNp-GlcNAcn, n = 1 to 5), and colloidal chitin as the substrates. The enzyme hydrolyzed GlcNAc4 to two molecules of GlcNAc2, GlcNAc5 to GlcNAc2 plus GlcNAc3, and GlcNAc6 by two ways to GlcNAc2 plus GlcNAc4 (87%), and two molecules of GlcNAc3 (13%). Neither GlcNAc2 nor GlcNAc3 was hydrolyzed. The Km and kcat were 0.249 mm and 3.38 sec−1 for GlcNAc4,0.018 mm and 2.67 sec−1 for GlcNAc5, and 0.005 mm and 2.72 sec−1 for GlcNAc6, respectively. The cleavage patterns of p-nitrophenyl N-acetylchitooligosaccharides were different from those of the corresponding N-acetylchitooligosaccharides. The enzyme hydrolyzed colloidal chitin to produce mainly GlcNAc2 and a trace of GlcNAc3. Allosamidin inhibited prawn chitinase in a competitive way with a Ki of 0.1 μm and IC50 of 0.14 μm. These results suggest that p...