Identification of Non-specific Trichoderma viride Producing Bifunctional Enzyme

[Objective] The property of the bifunctional enzyme CCBE Ⅱ,introduced by Trichoderma viride,with the degradation activity of chitosan and cellulose was researched and its type was identified.[Method] With the method of dinitrosalicylic acid(DNS) the enzyme activity of chitosan and cellulase was tested and the effect of the temperature of enzyme,the stability of pH value,the specificity of substrate,the metal ion and others on enzyme property was studied.[Results] The optimum temperature of the bifunctional enzyme CCBE Ⅱ for chitosan and carboxyn methyl cellulose sodium(CMC) was 60 ℃,the optimum pH value of the bifunctional enzyme CCBE Ⅱ for chitosan and CMC was 5.2 and 4.2,respectively,the metal ion: Mn2+,Mg2+,had the activation to the activity of both enzymes and Fe3+,Cu2+,Ag+ and Hg2+,strongly inhibition.The CCBE Ⅱ was with considerable degradation energy to the CMC and chitosan(84% deacetylated) but no degradation activity to p-nitrophenyl-β-D-glucopyranoside.The bond of GlcN-GlcN,GlcNAc-GlcN or the bond of GlcN-GlcNAc could be hydrolyzed while the CMC was cut with disaccharide form and the chitosan was cut with single sugar.The identification indicated that there was high homology between CCBE Ⅱ and the sequence of CBH Ⅰ(gi | 295937) produced by Trichoderma viride in glycoside hydrolase family 7 and the β-sheet was main form in its secondary structure.[Conclusion] The property of the bifunctional enzyme CCBE Ⅱ and the bifunctional enzyme purified from the commercial cellulase preparation was basically with the same nature and both of them was consisted of by same protein.And the identification indicated that it was the CBH Ⅰactually having the activity of exonuclease chitosan,belonging to glycoside hydrolase family 7.