title: [Activity of the enzyme of the 2d step of flavinogenesis, 2,5-diamino-6-hydroxy-4-ribosylaminopyrimidine-5'-phosphate reductase, in Pichia guilliermondii yeasts].
abstract: The activity of 2,5-diamino-6-hydroxy-4-ribosylaminopyrimidine-5'-phosphate reductase, an enzyme of the second step of flavinogenesis, was studied in the yeast Pichia guilliermondii using a new fluorimetric technique. The activity of the enzyme was found in extracts of the wild-type strain and the genotype rib mutants but not in extracts of the FM 1-4 (rib 2) mutant. Interallelic complementation was revealed in the gene rib 2. The activity of the enzyme was identical in extracts of the cells grown in the medium with either a high or a low iron content which synthesized riboflavin at a low or a high rate, respectively. Therefore, the synthesis of this enzyme in P. guilliermondii is not regulated with iron.
mesh_terms: D001203:Ascomycota / Q000378:metabolism*; D003470:Culture Media / Q000378:metabolism; D005415:Flavins / Q000096:biosynthesis*; D005838:Genotype; D007501:Iron / Q000378:metabolism; D009154:Mutation; D010843:Pichia / Q000378:metabolism*; D013401:Sugar Alcohol Dehydrogenases / Q000378:metabolism*
chemical_list: D003470:Culture Media; D005415:Flavins; D007501:Iron; D013401:Sugar Alcohol Dehydrogenases; C033549:2,5-diamino-6-hydroxy-4-ribosylaminopyrimidine-5'-phosphate reductase
vernacular_title: Ob aktivnosti fermenta vtorogo étapa flavinogeneza 2,5-diamino-6-oksi-4-ribozilaminopirimidin-5'-fosfatreduktazy u drozhzheĭ Pichia guilliermondii.