Isolation and identification of green fluorescent compound accumulated in non-growing cells of Eremothecium ashbyii by the addition of glyoxal.

The addition of a trapping agent, glyoxal, to a non-growing cell medium with Eremothecium ashbyii brought about the accumulation of large quantities of a green fluorescent compound, with a simultaneous rigid inhibition of riboflavin formation. The fluorescent compound was isolated from the mycelia after non-growing cell incubation and highly purified to a crystalline form through various column chromatographic steps. The purified compound was identified as 8-ribityllumazine by comparison with a synthetized reference compound by means of spectrophotometric and fluorometric measurements. Furthermore, it was verified that glyoxal, at the added concentration, and 8-ribityllumazine, at the accumulated concentration, caused slight inhibition of riboflavin formation with riboflavin synthetase from E. ashbyii. Accordingly, it was concluded that the 8-ribityllumazine accumulated is a derivative compound of an intermediate in flavinogenesis which is 4-ribitylamino-5-amino-2,6-dihydroxypyrimidine based on the trapping action of glyoxal.