Mycobacteria are able to produce nicotinic acid and 3‐hydroxymethylpyridine (pyridine‐3‐carbinole). Experiments using growing cells of Mycobacterium bovis strain BCG showed that applied 14C‐labelled nicotinic acid is utilized to form radioactive 3‐hydroxymethylpyridine. The resulting incorporation rate was comparatively high. On feeding resting cells with 3‐hydroxymethyl‐[4,6‐14C]pyridine, the reverse reaction was also noticed.
Isolated end‐products were degraded to estimate the isotope distribution. The radioactivity of applied [carboxy‐14C]nicotinic acid was almost entirely found in the carbinolic moiety of the isolated pyridine‐3‐carbinole, whereas the label of administered 3‐hydroxymethyl‐[4,6‐14C]‐pyridine was localized in the pyridine nucleus of the isolated nicotinic acid.
Results obtained from these feeding experiments showed a direct biogenetic relationship between nicotinic acid and pyridine‐3‐carbinole.