Evidence for a novel metabolic pathway of (ADP-ribose)n: pyrophosphorolysis of ADP-ribose in HeLa S3 cell nuclei |
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| Authors: | S Tanuma |
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| Affiliation: | Department of Physiological Chemistry, Faculty of Pharmaceutical Sciences, Teikyo University, Kanagawa, Japan. |
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| Abstract: | ADP-ribose liberated from (ADP-ribose)n by the action of (ADP-ribose)n glycohydrolase was converted to ATP and ribose 5-phosphate (ribose 5-P) in the presence of pyrophosphate (PPi) in HeLa S3 cell nuclei. This reaction was reversible and dependent on the simultaneous presence of ADP-ribose, PPi, Mg2+, and nuclei. These results suggest the presence of a novel enzyme in the nuclei, designated as ADP-ribose pyrophosphorylase, which catalyzes the reaction shown in Equation 1. ADP-ribose + PPi in equilibrium ATP + Ribose 5-P (1) This reaction could represent a pathway for the biosynthesis of ATP from (ADP-ribose)n in eukaryotic cell nuclei. |
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