FOOD SCIENCE ›› 2019, Vol. 40 ›› Issue (20): 144-151.doi: 10.7506/spkx1002-6630-20190419-256

• Bioengineering • Previous Articles     Next Articles

ZENG Jing, GUO Jianjun, TU Yikun, WEI Guowen, YUAN Lin

ZENG Jing, GUO Jianjun, TU Yikun, WEI Guowen, YUAN Lin   

  1. (1. Institute of Microbiology, Jiangxi Academy of Sciences, Nanchang 330096, China; 2. School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211800, China)
  • Online:2019-10-25 Published:2019-10-25

Abstract: In order to determine the effect of domain C of thermoacidiphilic raw starch-degrading α-amylase Gt-amy on its catalytic properties, circulation permutation based on protein molecular structure was used to construct circularly permutated mutants of Gt-amy. The abilities of Gt-amy and the mutants to adsorb onto and hydrolyze raw corn starch were investigated. Moreover, the specific activities and kinetic constants were also measured. Compared with Gt-amy, the mutants with higher raw corn starch-binding capacity had higher raw corn starch degradation capacity, and those with lower raw corn starch binding capacity had lower raw corn starch degradation capacity, i.e, there was a positive correlation between Gt-amy’s capacity to bind to and degrade raw corn starch. The raw corn starch binding and degradation rates of mutant Gt-amy-S498 were 93.14% and 90.93%, respectively, which were higher than those of Gt-amy (78.86% and 65.80%). This study confirms that circulation permutation can be used as an engineering method to change the structure and function of proteins, and provides a new way to improve the catalytic performance of enzymes.

Key words: thermoacidiphilic raw starch degrading α-amylase, circulation permutation, raw starch binding, raw starch hydrolysis, catalytic performance

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