Riboflavin biogenesis

All studies of the mechanism of riboflavin synthesis employing radioactive tracers, and the isolation of possible precursors in the biogenesis of the vitamin, have been carried out with the highly flaviogenic ascomycetes, Aahbya goaaypii or Eremothedum aahbyii. 

It has been found that the pattern of incorporation of labeled compounds into rings B and C is very much akin to that observed in the biosynthesis of the purines (71). Thus, the carbons from added formate and carbon dioxide were located in positions 2 and 4 respectively, and those from glycine in carbons 4a and 9a. The nitrogen of glycine has been recovered in the 9 plus 10 nitrogen portion of riboflavin (7 ) (see Table IV). If the analogy with purine biogenesis holds, the label should be located in position 10. 

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