科研之友
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摘要
Chaetomium thermophilum is a thermophilic fungus expressed a series of glycoside hydrolases. Genome sequence analysis of C. thermophilium revealed that ctcel6 gene encoded a putative cellobiohydrolase which composed of 397 amino acid residues including a predicted signal peptide sequence. Ctcel6 gene was cloned, heterologously expressed in Pichia pastoris and purified by Ni2+ affinity chromatography. Sequence alignment indicated that CtCel6 enzyme belonged to glycoside hydrolase family 6 (GH6) and the molecular mass of purified recombinant enzyme CtCel6 was 42 kDa by SDS- PAGE analysis. Characterization of recombinant CtCel6 exhibited high hydrolysis activity and excellent thermostability. The optimum reaction temperature and pH was 70 degrees C and pH 5, respectively. The bivalent metallic cations Mg2+ and Ca2+ significantly enhanced the activity of CtCel6. The specific activity of CtCel6 enzyme was 1.27 U/mg and Km value was 0.38 mM on beta- Dglucan. The substrate specificity and hydrolysis products insisted that CtCel6 was an exo-/endo-type cellobiohydrolase. The biochemical properties of recombinant CtCel6 made it potentially effective for bioconversion of biomass and had tremendous potential in industrial applications such as enzyme preparation industry and feed processing industry.
- 出版日期2017
- 单位山东农业大学
