[Adenine effect on the biosynthesis of 5'-inosinic acid by the mutant Brevibacterium ammoniagenes 225-5].

The effect of a temperature rise from 28 to 37 degrees C on the biosynthesis of 5'-inosine acid (IMP) by the mutant Brevibacterium ammoniagenes 225-5 was studied. The inhibitory effect of increased temperature on the IMP biosynthesis was dependent on the adenine concentration. The study of IMP synthesis on the media with different adenine concentrations showed that adenine controlled not only the synthesis of purines de novo but also, to a larger extent, so-called salvage IMP synthesis from hypoxanthine. The effect of increased temperature was identical to that of excessive adenine. Temperature rise as well as increase in adenine concentration intensified metabolic processes (increased the level of glucose consumption and the rate of nucleic acid synthesis) and restored in part cell permeability. This was indicated by the release of protein and ribose-5-phosphate into the culture fluid, and by the change in cell morphology. An optimal adenine concentration may be altered either way in response to the changes in other fermentation conditions, i.e. inoculum amount, aeration, and addition of histidine.