Matsui H, Shimaoka M, Takenaka Y, Kawasaki H, Kurahashi O
Fermentation & Biotechnology Laboratories, Ajinomoto Co., Inc., Kawasaki-shi, Kanagawa, Japan.
Biosci Biotechnol Biochem. 2001 May;65(5):1230-5. doi: 10.1271/bbb.65.1230.
We tried some improvement of inosine production using an inosine-producing mutant of Escherichia coli which is deficient in purF (phosphoribosylpyrophosphate (PRPP) amidotransferase gene), purA (succinyl-adenosine 5'-monophosphate (AMP) synthetase gene), deoD (purine nucleoside phosphorylase gene), purR (purine repressor gene) and add (adenosine deaminase gene), and harboring the desensitized PRPP amidotransferase gene as a plasmid. The guaB (inosine 5'-monophosphate (IMP) dehydrogenase gene) disruption brought about a slightly positive effect on the inosine productivity. Alternatively, the gsk (guanosine-inosine kinase gene) disruption caused a considerable amount of guanosine accumulation together with a slight increase in the inosine productivity. The further addition of guaC (guanosine 5'-monophosphate (GMP) reductase gene) disruption did not lead to an increased guanosine accumulation, but brought about the decrease of inosine accumulation.
我们尝试利用一株产肌苷的大肠杆菌突变体来提高肌苷产量。该突变体缺失purF（磷酸核糖焦磷酸（PRPP）酰胺转移酶基因）、purA（琥珀酰腺苷5'-单磷酸（AMP）合成酶基因）、deoD（嘌呤核苷磷酸化酶基因）、purR（嘌呤阻遏蛋白基因）和add（腺苷脱氨酶基因），并作为质粒携带脱敏的PRPP酰胺转移酶基因。guaB（肌苷5'-单磷酸（IMP）脱氢酶基因）的破坏对肌苷生产力产生了轻微的积极影响。另外，gsk（鸟苷-肌苷激酶基因）的破坏导致大量鸟苷积累，同时肌苷生产力略有增加。进一步破坏guaC（鸟苷5'-单磷酸（GMP）还原酶基因）并没有导致鸟苷积累增加，反而导致肌苷积累减少。
