Enzymatic characteristics of a recombinant protease (rPepD) from Aspergillus niger expressed in Pichia pastoris

Publication date: October 2019Source: Protein Expression and Purification, Volume 162Author(s): Ye Ke, Meng-yao Wei, Yu-tong Fu, Yan-mei Zhu, Xuan-lin ZhanAbstractThe Aspergillus niger AS3.350 protease gene (pepD) was successfully cloned and expressed in Pichia pastoris KM71. The rPepD activity was 331.5 U/ml, and the optimum temperature and pH were 45 °C and 8–9 respectively. In addition, enzyme activity was significantly inhibited by PMSF, EDTA, Mg2+, Fe2+ and Zn2+ ions, and stimulated by Ca2+ which selectively bound to the T302 and D323 residues. Mutation in either or both of the residues inhibited rPepD expression, indicating that binding to Ca2+ is necessary for PepD expression and activity. The rPepD showed a wide substrate range, and was particularly selective to those with hydrophobic amino acids. The degree of rPepD-mediated hydrolysis of soy protein isolate, corn flour and gluten meal were 8.7%, 38.1% and 33.6% respectively, which was higher than that by Alcalase, indicating that rPepD has potential applications in the food processing industry.
Source: Protein Expression and Purification - Category: Biochemistry Source Type: research

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Source: Molecules - Category: Chemistry Authors: Tags: Article Source Type: research
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Source: Journal of Microbiological Methods - Category: Microbiology Source Type: research
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