关键词:

谷氨酰胺, 酶催化, 谷氨酰胺合成酶, 腺苷酰化位点

Abstract:

To solve putative adenylation of glutamine synthetase (GS) in the enzymatic production of glutamine at a high concentration of ammonium salt, glnA encoding GS was cloned from Corynebacterium glutamicum ATCC 14067 and mutated by overlapping primer to replace the putative adenylation site of GS, Tyr405 by Phe405.The mutant GS was expressed in E.coli and the conditions of GS production were optimized.In the process catalyzed by the mutant GS,glutamine production was increased by adding monosodium glutamate and ammonium chloride in shaking flasks and glutamine yield reached 16.8 g·L^-1.By controlling the enzymatic conditions in 5 L bioreactor, glutamine yield reached 34.2 g·L^-1 with a molar conversion of 96.3% to glutamate.

Key words:

谷氨酰胺, 酶催化, 谷氨酰胺合成酶, 腺苷酰化位点