title: [Regulation of the activity and synthesis of enzymes participating in the formation of 6,7-dimethyl-8-ribityllumazine, a riboflavin precursor in yeast].
abstract: The properties of two flavinogenesis enzymes--synthase of the aliphatic precursor of riboflavin (APR-synthase) and 6.7-dimethyl-8-ribityllumazinesynthase (DMRL-synthase) of Pichia guilliermondii. It is established that DMRL-synthase, uses APR as a substrate which contains, evidently, a phosphate group. The value of Km for APR is equal to 0.7.10(-5) M, for 2.4-dihydroxy-5-amino-6-ribitylaminopyrimidine--1.25.10(-5) M. It is riboflavin but not FAD that inhibits the activity of DMRL-synthase; the value (I)0.5 is equal to 2.10(-5) M. DMRL, riboflavin, flavin mononucleotide and FAD do not affect the APR-synthase activity. In iron-deficient cells of P. guilliermondii, Torulopsis candida, Debaryomyces klöckeri and Schwanniomyces occidentalis realizing the oversynthesis of riboflavin there occurs derepression of DMRL-synthase and APR-synthase.
authors.forename: E M
authors.initials: EM
authors.lastname: Logvinenko
authors.forename: G M
authors.initials: GM
authors.lastname: Shavlovskiĭ
authors.forename: A E
authors.initials: AE
authors.lastname: Zakal'skiĭ
authors.forename: V A
authors.initials: VA
authors.lastname: Samarskiĭ
mesh_terms: D002175:Candida / Q000378:metabolism / Q000502:physiology; D005182:Flavin-Adenine Dinucleotide / Q000502:physiology; D007700:Kinetics; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D010843:Pichia / Q000201:enzymology* / Q000378:metabolism; D011621:Pteridines / Q000378:metabolism*; D012256:Riboflavin / Q000096:biosynthesis* / Q000502:physiology; D004718:Saccharomycetales / Q000201:enzymology*; D015003:Yeasts / Q000378:metabolism / Q000502:physiology
chemical_list: D009097:Multienzyme Complexes; D011621:Pteridines; D005182:Flavin-Adenine Dinucleotide; C001061:6,7-dimethyl-8-ribityllumazine; C044822:6,7-dimethyl-8-ribityllumazine synthase; D012256:Riboflavin
vernacular_title: Reguliatsiia aktivnosti i sinteza fermentov, uchastvuiushchikh v obrazovanii predshestvennika riboflavina-- 6,7-dimetil-8-ribitilliumazina u drozhzheĭ.