[Operon of riboflavin biosynthesis in Bacillus subtilis. XVI. Localization of the ribC-group markers on the chromosome].

Regulatory markers of ribC group were located on the chromosome of Bacillus subtilis by means of genetic transformation. Markers of this group controlling the regulation of riboflavin biosynthesis were mapped between markers of resistance to acriflavin and streptomycin (strC group). The value of cotransfer index between acriflavin-resistance markers and ribC markers was found to be 26--32%.

[Riboflavin biosynthesis operon of Bacillus subtilis. XIV. Operator-constitutive mutants].

Numerous operator-constitutive mutants of riboflavin biosynthesis were selected. All of them map in a short region of the Bacillus subtilis chromosome. The yield of riboflavin synthetase from this mutant is different, but in most cases much lower than the maximal yield from a repressor minus strain.

[Operon of riboflavin biosynthesis in Bacillus subtilis. XV. A study of mutants related to the initial stages of biosynthesis. The origin of the ribityl chain of the riboflavin molecule].

The incorporation of 14C-labelled guanosine and xanthosine into riboflavin was studied. It is concluded that the ribose mojety of guanosine is converted to the ribityl side chain of riboflavin. Thus the immediate precursor of riboflavin biosynthesis is a guanosine compound.

[Operon study of riboflavin biosynthesis in Bacillus subtilis. XII. The determination of the ATP:riboflavin-5'-phosphotransferase and riboflavinsynthetase content in the cells with varying genotypes].

Activities of riboflavinkinase and riboflavinsynthetase were measured in 15 strains of Bacillus subtilis with different genotype. The increased level of riboflavinkinase was observed in strains, resistant to lumiflavin or lumichrome. Specific activity of riboflavinkinase was found to be about 100 times lower than that of riboflavinsynthetase.

[Riboflavin biosynthesis operon of Bacillus subtilis. XIII. Genetic and biochemical study of mutants with regard to intermediate stages of biosynthesis].

New riboflavin dependent mutants of Bacillus subtilis accumulating different pteridines were studied. The data obtained show that the formation of ribityl side chain proceeds in a few steps at least on a part of riboflavin precursors. The oxidation of connected ribosyl into ribulose with subsequent restoration of it into ribityl proceeds at first.