Rapid and quantitative separation of nicotinamide and its N1-methylated metabolite by Dowex AG50-X4 chromatography.

The use of column chromatography with Dowex AG50-X4 resin has allowed the quantitative separation of nicotinamide from its primary metabolite, N1-methylnicotinamide. Although the sensitivity is similar to earlier high-performance liquid chromatographic methods, this procedure allows multiple assays to be carried out simultaneously in a matter of minutes. This method should be useful to study nicotinamide methyltransferase activity in either whole cells or extracts, and is particularly well suited to screen column fractions for enzyme purification purposes.