Examination of the structure of an unknown green fluorescent compound, compound G2, accumulated in non-growing cells of Eremothecium ashbyii by the addition of dimeric diacetyl

• Published in: Journal of nutritional science and vitaminology 1977-01, Vol.23 (5), p.413-422
• Main Authors: Mitsuda, H, Nakajima, K, Yamada, Y
• Format: Article
• Language: English
• Subjects: Ascomycota - metabolism; Butanones - pharmacology; Diacetyl - pharmacology; Fluorescence; Pteridines - metabolism; Pyrimidines - isolation & purification; Pyrimidines - metabolism; Riboflavin - biosynthesis; Ribose - analogs & derivatives; Ribose - metabolism; Saccharomycetales - metabolism; Spectrophotometry
• ISSN: 0301-4800; 1881-7742
• DOI: 10.3177/jnsv.23.413

The addition of dimeric diacetyl to Eremothecium ashbyii caused simultaneous accumulation of two green fluorescent compounds with the inhibition of riboflavin formation in non-growing cells. One compound, referred to as Compound G1, was identified as 6, 7-dimethyl-8-ribityllumazine as reported previously and the other is referred to as Compound G2. The latter compound was considered to be 6-methyl-7-(2-hydroxy-2-methyl-3-oxobutyl)-8-ribityllumazine because a violet fluorescent compound, 6-methyl-7-hydroxy-8-ribityllumazine was derived from Compound G2 in the presence of p-quinone and because the known action mechanism of dimeric diacetyl as a trapping agent of possible intermediates in the biosynthetic pathway. The results indicate that an immediate intermediate to 6, 7-dimethyl-8-ribityllumazine in the biosynthetic pathway of riboflavin is 4-ribitylamino-5-amino-2, 6-dihydroxypyrimidine, whose pyrimidine portion is derived by the elimination of a dimeric diacetyl fragment from the molecule of the isolated lumazine.