title: [Alterations in the excess synthesis of riboflavin in Pichia guilliermondii under the influence of branched-chain amino acids].
abstract: The effect of the branched-chain amino acids: L-valine, L-isoleucine and L-leucine on riboflavin overproduction was studied in the Pichia (Candida) guilliermondii (Cast.) Lang. et G. yeast, L-Val, L-Ile and L-Leu were found to inhibit riboflavin overproduction only under iron-deficient growth conditions. Other amino acids used did not show this effect. In crude extracts of P. guilliermondii the specific activity of the alpha-acetolactate forming enzyme, pH 8.0, is inhibited by L-Val. It is revealed that the activity of alpha-acetolactate synthetase in iron-deficient riboflavin-overproduction cells was exceedingly higher than in the valine-inhibited cells. Under iron deficiency alpha-acetolactate synthetase shows maximal activity after 48 h of growth. It was possible to detect diacetyl (and aceton) in the culture fluid.
mesh_terms: D000095:Acetolactate Synthase / Q000378:metabolism; D000596:Amino Acids / Q000494:pharmacology*; D001203:Ascomycota / Q000378:metabolism*; D007501:Iron / Q000494:pharmacology; D007532:Isoleucine / Q000494:pharmacology; D007930:Leucine / Q000494:pharmacology; D010843:Pichia / Q000378:metabolism*; D012256:Riboflavin / Q000096:biosynthesis*; D014633:Valine / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D007532:Isoleucine; D007501:Iron; D000095:Acetolactate Synthase; D007930:Leucine; D014633:Valine; D012256:Riboflavin
vernacular_title: Izmeneniia sverkhsinteza riboflavina u drozhzheĭ Pichia guilliermondii pod vliianiem aminokislot s razvetvlennymi bokovymi tsepiami