Synthesis of riboflavin by microorganisms. I. The metabolic function of aspartate in the riboflavin synthesis by Clostridium acetobutylicum.

Abstract

1. Oxaloacetate, fumarate, pyruvate and lactate which are the metabolites of aspartate, were all stimulatory on the flavinogenesis by Cl. acetobutylicum. α-Ketoglutarate and L-malate were not active, the latter being inhibitory to riboflavin biosynthesis.2. Aminofumaric acid diamide was stimulative, but its effect was less than fumarate.3. None of the amino acids tested could replace L-aspartate in riboflavin biosynthesis. DL-Serine was much effective on the synthesis. DL-Serine and L-aspartate play the same role in the synthesis. Glycine was not effective in the experiments using growing cells.4. Adenine, hypoxanthine, uracil, orotic acid and 2-amino-4-hydroxypteridine-6-carboxylic acid were inactive on the flavinogenesis in the experiments using resting cells. The growth and riboflavin formation of this microorganism were not inhibited by the addition of sulfanilamide and p-amino-salicylic acid in the presence of p-aminobenzoic acid and folic acid.