关键词: 甲基对硫磷水解酶;分泌;热稳定性;毕赤酵母

Abstract:

Methyl parathion hydrolase can biodegrade organophosphorus pesticides. Due to its special application value, researchers paid more and more attension. Wild-type MPH-Och from Ochrobactrum sp. could not be secreted in Pichia pastoris. In order to increase the secretion level, the MPH-S274Q mutant, which thermal stability was increased, was expressed in Pichia pastoris. After recombinant strain was induced by shaking culture flask for 120 h, the enzyme activity of culture supernatant reached 0.7 U/mL. It was 14 times of that in wild type MPH-Och. The SDS-PAGE electrophoresis showed that the culture supernatant of mutant MPH-S274Q had a distinct protein band, which further proved the improvement of secretion efficiency. This study indicated that improving protein thermal stability can be an effective way to increase secretion efficiency of exogenous protein in Pichia pastoris.

Key words: methyl-parathion hydrolase, secretion, thermal stability, Pichia pastoris