精氨酸脱亚胺酶发酵过程特性研究

Investigation of fermentation process of arginine deiminase in Enterococcus faecalis

精氨酸脱亚胺酶有较好的体内体外肿瘤生长抑制作用。通过对粪肠球茵(Enterococcus faecalis)NJ402菌株产精氨酸脱亚胺酶的发酵特性的研究,建立起代谢物的过程变化与精氨酸脱亚胺酶产生机理的内在联系。NJ402菌株生长过程中碳源物质代谢产生乳酸导致发酵体系pH的下降,而培养基中L-精氨酸的脱亚胺作用有利于发酵体系pH的稳定和茵体生长。进一步的研究表明,低pH生长环境有利于NJ402菌株产精氨酸脱亚胺酶,且精氨酸脱亚胺酶的产生与能量代谢无关。NJ402菌株产精氨酸脱亚胺酶受底物L-精氨酸的诱导,但该诱导作用受茵体生长体系pH的调控,即精氨酸脱亚胺酶的产生是低pH生长环境与L-精氨酸共同作用的结果。

Arginine deiminase （ADI） is a potential anticancer agent. Studies on the characteristics of fermentation and mechanism of expression of ADI were the basic works for ADI availability. The process characteristics and the major intermediates in the fermentations of ADI in Enterococcuss faecalis NJ402 were determined. A theory about the expression of ADI with the process of fermentation was proposed. In the earlier process of fexmentation, the value of pH in fermentor was degressive to 5.5 for the secretion of lactic acid with catabolism of gluoose in the cells of NJ402, while the value of pH was improved gradually with production of ammonia in the process of biocatalysis of ADI with arginine. The improved pH was available to the growth of NJ402. ADI expression in NJ402 was presumed to be contacted with the regulation of pH, and the degressive value of pH was the evocating agent. When NaOH was added to the system to keep the value of pH invariablenes, the specific activity of ADI was lower. ADI could not be evocative by the shortage of energy metabolism. Expression of ADI in NJ402 was induced by L-arginine and the process was regulated and controlled by pH in vitro .