The deamido-diphosphopyridine nucleotide and diphosphopyridine nucleotide pyrophosphorylases of Escherichia coli and yeast

The DPN (deamido-DPN) pyrophosphorylases of yeast and Escherichia coli B were partially purified and their properties were studied. The data suggested that one enzyme in each organism catalyzed the synthesis and pyrophosphorolysis of both deamido-DPN and DPN. The rate of synthesis of deamido-DPN is about two times greater than the rate of synthesis of DPN when catalyzed by the yeast enzyme. The rate of deamido-DPN synthesis is 17 times greater than the rate of DPN synthesis in reaction mixtures containing the E. coli enzyme. Both enzymes are specific for ATP and deoxy-ATP. All other nucleoside triphosphates were inactive in forming dinucleotides.