Identification of the second product of the riboflavin synthetase reaction.

Effects of various metabolites (sugars, carboxylic acids and alcohols) on riboflavin formation in non-growing cells of Ashbya gossypii.

“…91 We previously reported that guanosine triphosphate (1-3) is the most direct nucleotide precursor and is converted to riboflavin via 4-(1'-D-ribitylamino)-5 -amino-2, 6-dihydroxypyrimidine (4,5). In addition, we demonstrated the clear identity of structures (6) and functions (7) in differentiating between the pyrimidine intermediate and the byproduct formed in the riboflavin synthetase reaction. While, BACHER and LINGENS (8,9) and LOGVINENKO et al (10) detected two pyrimidines, thought to be intermediates or their derivatives, 2, 4, 5-triamino-6 -hydroxypyrimidine and 4-(1'-D-ribitylamino)-2, 5-diamino-6-hydroxypyrimidine from the mutants of yeast.…”

The immediate nucleotide precursor, guanosine triphosphate, in the riboflavin biosynthetic pathway.

“…5. In the figure it is concluded that after the rupture of the imidazole ring, GTP is con verted to riboflavin through an immediate intermediate, 4-ribitylamino-5-amino -2, 6-dihydroxypyrimidine (25), which is also the by-product of the riboflavin synthetase reaction (26) and is probably reutilized for the formation of riboflavin in vivo (27). The pyrimidine which is the precursor or the by-product on the pathway was isolated in the form of 8-ribityllumazine or 6-methyl-7-(2-hydroxy -2-methyl-3-oxobutyl)-8-ribityllumazine from the mold or the enzyme reaction mixture, using glyoxal or dimeric diacetyl as trapping agents in these experiments.…”

Purification and some properties of riboflavin synthetase from Bacillus stearothermophilus ATCC 8005

“…tylamino-5-aminouracil (11,15). The catalytic properties ofriboflavin synthetases from Ashbya gossypii (13), Eremothecium ashbyii (19), Escherichia coli (13), yeast (6,14), and spinach (9,10) have already been investigated.…”