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›› 2008, Vol. 8 ›› Issue (2): 350-354.

• 生化工程专栏 • 上一篇    下一篇

曲霉产壳聚糖酶的水解作用模式

陈小娥 方旭波 余辉 夏文水   

  1. 浙江海洋学院食品与药学学院 浙江海洋学院食品与药学学院 浙江海洋学院食品与药学学院 江南大学食品科学与安全国家教育部重点实验室
  • 收稿日期:2007-11-13 修回日期:2008-01-21 出版日期:2008-04-20 发布日期:2008-04-20
  • 通讯作者: 陈小娥

Hydrolytic Model of Chitosanases Produced with Aspergillus CJ22-326

CHEN Xiao-e FANG Xu-bo YU Hui XIA Wen-shui   

  1. School of Food and Pharmacy, Zhejiang Ocean University School of Food and Pharmacy, Zhejiang Ocean University School of Food and Pharmacy, Zhejiang Ocean University The Key Laboratory of Food Science and Safety, Ministry of Education, Jiangnan University
  • Received:2007-11-13 Revised:2008-01-21 Online:2008-04-20 Published:2008-04-20
  • Contact: CHEN Xiao-e

摘要: 从曲霉CJ22-326发酵培养液中分离纯化得到2种壳聚糖酶组分(ChiB, ChiA),通过测定酶解液体系粘度和对酶解产物进行TLC和HPLC分析,对其水解模式的研究结果表明,酶ChiB是一种内切壳聚糖酶,以随机进攻方式作用于壳聚糖分子链内部,从而使体系粘度快速下降. 以低聚糖为底物的水解产物分析表明,它作用于GlcN?GlcN糖苷键,不能作用于GlcNAc?GlcNAc糖苷键,不水解壳四糖及以下聚合度的甲壳低聚糖,壳五糖被水解成壳二糖和壳三糖,壳六糖主要被水解成壳三糖. 酶ChiA是一种外切氨基葡萄糖苷酶,主要从壳聚糖分子或甲壳低聚糖分子一端依次切下氨基葡萄糖残基,它只作用于GlcN?GlcN和GlcN?GlcNAc糖苷键.

关键词: 曲霉, 壳聚糖酶, 水解模式

Abstract: Hydrolytic model of two chitosanases of chitosan, ChiB and ChiA, separated and purified from a culture filtrate of Aspergillus CJ22-326, was investigated. The experimental results on the viscosity changes of reaction solution and analysis of enzymatic hydrolysis products by TLC and HPLC showed that ChiB was an endo-type cleavage enzyme. ChiB decreased the viscosity of reaction solution significantly, hydrolyzed b-(1,4) glucosidic bond of chitosan at random. Using chitooligosaccharides as substrates, ChiB acted on GlcN?GlcN and did not act on GlcNAc?GlcNAc glucosidic bond. Chitooligosaccharides with the degree of polymerization below 5 could not be hydrolyzed by ChiB. Hydrolysis products of chitopentose were chitobiose and chitotriose. The latter was the main product of chitohexaose hydrolysis. ChiA was an exo-type amino-glucosidase which mainly cleaved glucosamine residue from non-reducing end of chitosan or chitooligosaccharides. ChiA acted only on GlcN?GlcN and GlcN?GlcNAc glucosidic bonds.

Key words: Aspergillus, chitosanase, hydrolytic model

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