A method for the rapid separation and characterization of biological pyridines

Pyridine compounds of biological origin are separable by 2-dimensional descending paper chromatography. When assayed in situ for a tertiary or quaternary ring nitrogen, each compound gives a charactertistic reaction which is not predictable from the structural configuration. A cell-free extract of Escherichia coli, incubated in the presence of isoniazid, yields an ultraviolet light quenching spot with Rf values different from any tested standard. The compound is hypothesized to be a metabolite of either nicotinic acid or isonazid.