Evidence for a novel metabolic pathway of (ADP-ribose)n: pyrophosphorolysis of ADP-ribose in HeLa S3 cell nuclei.
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.
Tanuma
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Department of Physiological Chemistry, Faculty of Pharmaceutical Sciences, Teikyo University, Kanagawa, Japan.
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000469:Alkaline Phosphatase; D002467:Cell Nucleus / Q000378:metabolism; D011756:Diphosphates / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D006868:Hydrolysis; D007202:Indicators and Reagents; D007700:Kinetics; D010766:Phosphorylation
D011756:Diphosphates; D007202:Indicators and Reagents; D000246:Adenosine Diphosphate Ribose; D000249:Adenosine Monophosphate; D000255:Adenosine Triphosphate; D000469:Alkaline Phosphatase; D006026:Glycoside Hydrolases; C022407:poly ADP-ribose glycohydrolase