中文摘要：

采用HPLC、HPLC-MS及TLC等方法,研究了从纤维素酶中分离得到的既具有纤维素酶活又具有壳聚糖酶活--双功能酶的水解壳聚糖的专一性.通过对氨基低聚糖（GlcN）n、乙酰氨基低聚糖（GlcNAc）n标样及壳聚糖的双功能酶水解进程及水解产物分析,表明该双功能酶能水解（GlcN）n,而不能水解（GlcNAc）n,即它能水解GlcN-GlcN之间的β-1,4糖苷键,但不能水解GlcNAc-GlcNAc之间的糖苷键.不同脱乙酰度壳聚糖经酶水解,其产物大部分为单糖,壳聚糖脱乙酰度（DD）对水解反应产物的形成和反应速率影响较小,表明该酶也可作用于GlcN-GlcNAc之间的β-1,4糖苷键.运用Time-Course分析法对双功能酶水解壳四糖（GlcN）4的进程进行分析,表明其作用方式为外切,推测此双功能酶为一外切氨基葡萄糖苷酶.

英文摘要：

This paper investigated the chitosan specialty of a bifunctional enzyme, separated from cellulase with cellulase and chitosanase activities, by using TLC, HPLC, HPLC- MS. Data shows the enzyme could split GIcN - GIcN linkage other than GIcNAc- GIcNAc. The chitosan hydrolyzateds produced by the enzyme were GIcN, GIcNAc indicating this enzyme could split GIcN- GIcNAc also. Time - course of reaction catalysed by the bifunctional enzyme was studied using （GIcN）4 as the substrate. The enzyme hydrolysed （GIcN）4 in an exo - splitting manner producing （GIcN）3, （GIcN）a, and didn＇t catalyse transglycoslation. Products distribution was （GIcN）3 〉 （GIcN）2. It was suggested that this enzyme is an exo- type chitosanase and cleaved both GIcN - GIcN and GIcN - GlcNAc linkages.