The Function of Nicotinic Acid in Bacterial Metabolism

Abstract

Using Salmonella paratyphi A chiefly as test organism, it was found that nicotinic acid added in varying amts. to a carbohydrate-free synthetic or peptone medium does not appreciably affect growth. In the absence of nicotinic acid, glucose (and other fermentable carbohydrates) added to such a medium inhibits or may prevent growth. Nicotinic acid is not a specific growth-promoting substance. It plays an essential role in the fermentation of carbohydrates, and is essential for the complete utilization of lactic acid and more particularly for the oxidation of acetic acid. Dehydrogenation expts. indicate that nicotinic acid does not act as such but must first be converted to a cozymase-like substance (codehydrase). Such conversion occurs only in the living cell.