REVERSIBLE ENZYMATIC SYNTHESIS OF DIPHOSPHOPYRIDINE NUCLEOTIDE AND INORGANIC PYROPHOSPHATE

Abstract

Ochoa, Cori, and Cori (1) observed the production of inorganic pyrophosphate (PP) during the oxidation of glutamate, pyruvate, or succinate by dialyzed rat liver dispersions. They were able to show that the PP was not a result of simple hydrolysis of adenosine triphosphate (ATP), since ATP added to these preparations failed to yield PP. The release of PP from ATP by bone and snake venom phosphatases (2) and the occurrence of PP in molds (3) and in yeast (4) have also been described. Recent studies with washed kidney particles (5, 6) have confirmed the production of PP by respiring tissue preparations but have not clarified the mechanism involved. The mechanism of the biosynthesis of diphosphopyridine nucleotide (DPN) has also remained obscure. The only studies with cell-free systems were reported by Lennerstrand (7), who found that cozymase activity destroyed by incubation with apozymase could be partially restored when active fermentation took place. An enzyme has now been purified from yeast (8) and liver which catalyzes the reversible synthesis of DPN and PP according to equation (1).