1. Supplementation of cultures of Eremothecium ashbyii with ribitol leads to a twofold increase in riboflavin formation compared with unsupplemented cultures or those supplemented with ribose or ribulose phosphate. Addition of unlabelled ribitol decreases the incorporation of [1-14C]ribose into riboflavin, indicating that free ribitol is preferred to ribose for incorporation into riboflavin. 2. The enzymes ribitol kinase, d-ribose reductase, d-ribose 5′-phosphatase and GMP nucleosidase were demonstrated in the cell-free extracts. Ribitol induces the formation of ribitol kinase. The enzyme is activated in vitro by the flavinogenic purines, guanine and xanthine. d-Ribose reductase shows a specific requirement for NADPH and forms free ribitol from ribose. 3. The activities of ribitol kinase, ribose 5′-phosphatase and GMP nucleosidase reach their maximal values before riboflavin formation reaches a maximum. 4. [U-14C]GMP is taken up intact by the culture of E. ashbyii and is incorporated into riboflavin as well as into a blue fluorescent compound. The radioactivity from this compound is incorporated into riboflavin by the cell-free extract of E. ashbyii.
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Research Article|
November 01 1972
Ribitol and flavinogenesis in Eremothecium ashbyii
Smriti U. Mehta;
Smriti U. Mehta
1Department of Microbiology, Maharaja Sayajirao University of Baroda, Baroda-2, India
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A. K. Mattoo;
A. K. Mattoo
1Department of Microbiology, Maharaja Sayajirao University of Baroda, Baroda-2, India
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V. V. Modi
V. V. Modi
1Department of Microbiology, Maharaja Sayajirao University of Baroda, Baroda-2, India
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Publisher: Portland Press Ltd
© 1972 The Biochemical Society
1972
Biochem J (1972) 130 (1): 159–166.
Citation
Smriti U. Mehta, A. K. Mattoo, V. V. Modi; Ribitol and flavinogenesis in Eremothecium ashbyii. Biochem J 1 November 1972; 130 (1): 159–166. doi: https://doi.org/10.1042/bj1300159
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