[Regulation of L-asparaginase biosynthesis in mutants of Bacillus mesentericus 43A, poorly growing in the presence of aspartic acid].

Biosynthesis of L-asparaginase (EC 3.5.1.1) was inhibited in the growing culture of Bac. mesentericus 43A on addition of L-aspartic acid (20 mM). My treatment with methyl nitrosourea (2 mg/ml) mutants were obtained, which grew poorly on aspartic acid used as the only source of carbon and nitrogen. The aspartic acid did not repress the asparaginase biosynthesis in 8 strains, found between the mutants. In six of these mutants the asparaginase biosynthesis was inhibited by means of the type of catabolite repression. The data obtained suggest that in Bac. mesentericus 43A the asparaginase biosynthesis is controlled more likely by two independent mechanisms: 1) specific repression with aspartic acid as an end product and 2) catabolite repression.