Nicotinic Acid Biosynthesis: Control by an Enzyme that Competes with a Spontaneous Reaction
Alan H. Mehler 1,
Kunihiko Yano 2, and
Everette L. May 3
1 National Institute of Dental Research, Bethesda, Maryland
2 University of Maryland, College Park
3 National Institute of Arthritis and Metabolic Diseases, Bethesda, Maryland
Extracts of livers from diabetic rats contain normal amounts of the enzymes needed to convert 3-hydroxyanthranilic acid to nicotinic acid nucleotide. The decreased capacity of diabetic animals to synthesize nicotinic acid is therefore attributed to increased amounts of picolinic carboxylase, which competes for a common intermediate with the spontaneous reaction in which quinolinic acid is formed as a precursor of nicotinic acid. These studies were facilitated by the synthesis of 3-hydroxyanthranilic acid labeled with carbon-14 in positions 3 and 6