Identification of the second product of the riboflavin synthetase reaction.

This study was concerned with the detailed identification of the second product involved in the riboflavin synthetase reaction with riboflavin synthetase from Eremothecium ashbyii and a trapping agent, glyoxal.Thus, a green fluorescent compound accumulated during the incubation. The compound was purified through various column chromatography steps, and was examined by UV, IR, excitation and emission spectra and paper chromatography to prove that the isolated compound was 8-ribityllumazine. Accordingly it was concluded that a second product in riboflavin synthetase reaction was 4-ribitylamino-5-amino-2,6-dihydroxypyrimidine, the fragment, except for C-6 and C-7 of 8-ribityllumazine, being an incorporated glyoxal portion.