腺苷产生菌Xn151的产物积累机制

Mechanism of adenosine production by adenosine-producing strain Xn151

目的探索枯草芽孢杆菌黄嘌呤缺陷型突变株Xn151的腺苷积累机制。方法通过测定野生型菌株和突变株的相关酶活力和嘌呤系物质对腺苷积累的影响,判断出那些酶是腺苷生物合成途径中的关键酶。结果缺失腺嘌呤脱氨酶的黄嘌呤突变株Xn151能积累更多的腺苷,在发酵培养基中限量加入嘌呤系物质(鸟苷或腺嘌呤)能促进腺苷的积累,但超过一定的量则对腺苷积累不利。结论在黄嘌呤缺陷型突变株Xn151中限量供应嘌呤系物质(鸟苷或腺嘌呤)能够解除产物的反馈抑制。腺嘌呤脱氨酶的缺失能促进腺苷的积累。

Purpose The mechanism of adenosine production by xanthine-requiring mutant Xn151 derived from a Bacillus substilis strain was investigated. Methods The related enzyme activities were assayed in wild strain and a series of mutants, and the effect of purine-related substances on the adenosine accumulation was examined, and the key enzymes of adenosine biosynthesis were considered. Results The xanthine-requiring mutant Xn151 defective in adenase accumulated much adenosine. Limitation of the purine-related substances （guanosine or adenine）in the fermentation medium facilitated the adenine accumulation, but the excess of those suppressed it. Conclusion The xanthine-requiring mutant Xn151 could be released from both feedback inhibition and repression by limiting the concentration of he purine-related substances（guanosine or adenine）. Deficiency in the deaminase activities of adenine contributed to adenosine accumulation.