Metabolism of trigonelline.

During the germination of seeds and the early growth of plants, trigonelline (N-methylnicotinic acid) disappears and pyridine nucleotides appear in the plant tissue (1, 2). Hence, it has been surmised, albeit without direct evidence, that the trigonelline of the seeds is a precursor of pyridine nucleotides in seedling plants. In an earlier study from this laboratory (3), it was shown that preparations of peas synthesize trigonelline by methyl transfer from X-adenosylmethionine to nicotinic acid. In the present studies it has been shown that the yeast, Torula cremoris, which can utilize trigonelline, nicotinic acid, and nicotinamide, but not Nl-methylnicotinamide, for growth (4), can also utilize trigonelline as a source of nicotinic acid for diphosphopyridine nucleotide biosynthesis, and attempts were made to ascertain the mechanism of this conversion.