期刊
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
卷 81, 期 -, 页码 362-369出版社
ELSEVIER
DOI: 10.1016/j.ijbiomac.2015.08.026
关键词
Chitosanase; Aspergillus sp.; Glycoside hydrolyase family 75
资金
- Chinese High-Tech Research and Development Program [2011AA10A205, 2012AA021501, 2014AA093604]
- National Key Laboratory of Biochemical Engineering [2012KF-06]
- Chinese Academy of Sciences [KSZD-EW-Z-015-2]
A new chitosanase gene of glycoside hydrolase (GH) family 75, csnw2, was cloned from an isolated strain Aspergillus sp. W-2 (CGMCC7018). The mature CsnW2 protein, fused to His-tag at C-terminus, was expressed in Pichia pastoris X-33 and purified with the affinity chromatography of Ni2+-NTA. The novel recombinant CsnW2 showed maximal activity with chitosan at pH 6.0 and 55 degrees C. Moreover, it had good pH stability and thermostability at a broad pH range of 3.0-10.0 and a temperature range of 30-70 degrees C, respectively. The enzymatic activity of the CsnW2 could be significantly enhanced by Ca2+, Mn2+ and Mg2+ at a concentration of 1 mM, but strongly inhibited by Fe2+, Zn2+, Ge2+, Ni2+ and Cu2+ above 1 mM. The CsnW2 showed specific hydrolytic activity against chitosan and preferred to hydrolyze chitosan with high degree of deacetylation. The main products of chtiosan (92% deacetylation) were chitosan oligosaccharides (COS) with degree of polymerization (DP) arranging from 2 to 6. Combined with the hydrolysis of COS from DP2 to DP6, CsnW2 was considered to be an endo-acting chitosanase. (C) 2015 Elsevier B.V. All rights reserved.
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