抄録
In the present paper, the nucleotide precursor of riboflavin was investigated by experiments with labeled purines using non-growing cells of Eremothecium ashbyii.
The added purines, at 10-4 M, were effectively incorporated into ribo-flavin at an early stage of riboflavin biosynthesis under the experimental conditions. In particular, both labeled xanthine and labeled guanine were specifically transported to guanosine nucleotides, GMP, GDP, GDP-Mannose and GTP, in the cource of the riboflavin biosynthesis. A comparison of specific activities of labeled guanosine nucleotides and labeled riboflavin indicated that the nucleotide precursor of riboflavin is guanosine triphosphate. From the results obtained, a biosynthetic pathway of riboflavin is proposed under “DISCUSSION.”
