Biological deamidation of nicotinamide in vertebrates

Abstract

An enzyme bringing about the deamidation of nicotinamide was demonstrated for the first time in lactic acid bacteria and later in yeast and Mycobacteria. Studies in this laboratory have revealed the presence of nicotinamide-deamidating enzymes in Neurospora crassa and the insect larva Corcyracephalonica St. and that the predominant feature of the vitamin metabolism in these organisms is the deamidation of nicotinamide. In the course of a study of the comparative metabolism of the vitamin in a variety of organisms, the liver and the kidney of several vertebrates have been examined for nicotinamide deamidase activity. A cell-free homogenate of the tissue was prepared in ice-cold distilled water and the enzyme activity measured as described earlier.