The change of the fermentation product, the production of glutamic acid instead of ornithine, occurred by the addition to the medium of a large amount of L-arginine which is the growth factor of the amino acid producing organism, a mutant of Micrococcus glutamicus. The mechanism responsible for this change has been studied, referring to the biosynthetic pathway of ornithine of the organism. Evidence has been presented that arginine inhibits the phosphorylation of N-acetylglutamic acid, thus preventing the conversion of glutamic acid to ornithine. This inhibition is probably specific in action and according to the concept of the regulatory mechanism of biosynthesis is of a feedback-type in nature.
The Microbiology Research Foundation