title: [Regulation of synthesis of GTP-cyclohydrolase participating in yeast falvinogenesis by iron].
abstract: Pichia guilliermondii, Schwanniomyces occidentalis, Torulopsis candida and several riboflavin-dependent mutants of Torulopsis candida were grown in a medium with a low concentration of iron. In these conditions, the activity of GTP-cyclohydrolase which catalyzes the first step of flavinogenesis increases. The activity of the enzyme increases also when the cells of T. candida and P. guilliermondii with a high content of iron are incubated with alpha, alpha'-dipyridyl which induces overproduction of riboflavin; this action of alpha, alpha'-dipyridyl is eliminated by cycloheximide. Therefore, iron deficiency in the cells of these yeasts causes derepression of GTP-cyclohydrolase participating in riboflavin biosynthesis. The activity of the enzyme is inhibited by FAD but not by FMN and riboflavin.
mesh_terms: D000619:Aminohydrolases / Q000096:biosynthesis*; D002175:Candida / Q000201:enzymology; D006136:GTP Cyclohydrolase / Q000096:biosynthesis*; D007501:Iron / Q000502:physiology*; D010843:Pichia / Q000201:enzymology; D004718:Saccharomycetales / Q000201:enzymology; D015003:Yeasts / Q000201:enzymology*
chemical_list: D007501:Iron; D000619:Aminohydrolases; D006136:GTP Cyclohydrolase
vernacular_title: Reguliatsiia zhelezom sinteza GTF-tsiklogidrolazy, uchastvuiushcheĭ vo flavinogeneze drozhzheĭ.