曲霉产壳聚糖酶的水解作用模式  

Hydrolytic Model of Chitosanases Produced with Aspergillus CJ22-326

作　　者：陈小娥[1] 方旭波[1] 余辉[1] 夏文水[2] 

机构地区：[1]浙江海洋学院食品与药学学院,浙江舟山316000 [2]江南大学食品科学与安全国家教育部重点实验室,江苏无锡214122

出　　处：《过程工程学报》2008年第2期350-354,共5页The Chinese Journal of Process Engineering

基　　金：浙江省自然科学基金资助项目(编号:Y305119)

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。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 β-（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.

关 键 词：曲霉 壳聚糖酶 水解模式 

分 类 号：Q556.2[生物学—生物化学]