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Query: UMLS:C0240066 (iron deficiency)
 7,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
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PMID:[Regulation of synthesis of GTP-cyclohydrolase participating in yeast falvinogenesis by iron]. 56 Dec 94

Roots from iron-deficient sugar beet grown in the presence of calcium carbonate exhibit a yellow color and autofluorescence typical of flavin-like compounds, whereas roots of control, iron-sufficient plants exhibited no yellow color and extremely low autofluorescence. The two major flavins whose accumulation is induced by iron deficiency have been shown to be different from riboflavin, FMN, and FAD by reversed-phase high performance liquid chromatography. These flavins, accounting for 82 and 15% of the total flavin concentration in deficient roots, have been shown unequivocally to be riboflavin 3'-sulfate and riboflavin 5'-sulfate, respectively, by electrospray-mass spectrometry, inductively coupled plasma emission spectroscopy, infrared spectrometry, and 1H nuclear magnetic resonance. These flavin sulfates have not been found previously in biological systems. The localization of riboflavin sulfates in deficient roots is similar, but not identical, to that of high iron reductase activity. The concentration of riboflavin sulfates has been estimated from root extracts to be at least 1 mM. We hypothesize, based on the similar localization of flavin and that of iron reduction, that the accumulation of riboflavin sulfates induced by iron deficiency may be an integral part of the turbo iron-reducing system in sugar beet roots.
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PMID:Riboflavin 3'- and 5'-sulfate, two novel flavins accumulating in the roots of iron-deficient sugar beet (Beta vulgaris). 840 31