Purification and Characterization of Two Chitosanase Isoforms from the Sheaths of Bamboo Shoots
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- 作者：Shou-Kuo Hsu ; Yun-Chin Chung ; Chen-Tien Chang ; Hsien-Yi Sung
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2012
- 出版时间：January 18, 2012
- 年：2012
- 卷：60
- 期：2
- 页码：649-657
- 全文大小：381K
- 年卷期：v.60,no.2(January 18, 2012)
- ISSN：1520-5118
文摘
Two thermally stable chitosanase isoforms were purified from the sheaths of chitosan-treated bamboo shoots. Isoforms A and B had molecular masses of 24.5 and 16.4 kDa and isoelectric points of 4.30 and 9.22, respectively. Using chitosan as the substrate, both isoforms functioned optimally between pH 3 and 4, and the optimum temperatures for the activities of isoforms A and B were 70 and 60 掳C, respectively. The kinetic parameters Km and Vmax for isoform A were 0.539 mg/mL and 0.262 渭mol/min/mg, respectively, and for isoform B were 0.183 mg/mL and 0.092 渭mol/min/mg, respectively. Chitosans were susceptible to degradation by both enzymes and could be converted to low molecular weight chitosans between 28.2 and 11.7 kDa. Furthermore, the most susceptible chitosan substrates were 50鈥?0 and 40鈥?0% deacetylated for isoforms A and B, respectively. Both enzymes could also degrade chitin substrates with lower efficacy. N-Bromosuccinimide and Woodward鈥檚 reagent K strongly inhibited both enzymes.