title: Structure of poly(adenosine diphosphate ribose): identification of 2'-[1''-ribosyl-2''-(or 3''-)(1'''-ribosyl)]adenosine-5',5'',5'''-tris(phosphate) as a branch linkage.
abstract: Poly([14C]adenosine diphosphate ribose) was synthesized from [14C]NAD+ with calf thymus nuclei. The fraction containing poly(adenosine diphosphate ribose) eluted with 0.22--0.40 M phosphate buffer (pH 6.8) from a hydroxylapatite column, was completely hydrolyzed with venom phosphodiesterase, and was separated by DEAE-Sephadex A-25 column chromatography in 7 M urea. A new compound, which constituted 2% of the products from poly(adenosine diphosphate ribose), was found in addition to the expected products--i.e., 5'-AMP, 2'-(1''-ribosyl)adenosine-5',5''-bis(phosphate), and its derivatives. This compound was identified as 2'-[1''-ribosyl 2''-(or 3''-)(1'''-ribosyl)]adenosine-5',5'',5'''-tris(phosphate). The existence of this compound is evidence of a branching structure of poly(adenosine diphosphate ribose), which was previously thought to be a linear molecule. The content of this compound suggests that the frequency of branching is about 1 per 20--30 adenosine diphosphate ribose residues of high molecular weight poly(adenosine diphosphate ribose).
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D013058:Mass Spectrometry; D009243:NAD; D009702:Nucleoside Diphosphate Sugars / Q000032:analysis; D010084:Oxidation-Reduction; D010504:Periodic Acid; D010766:Phosphorylation; D011064:Poly Adenosine Diphosphate Ribose / Q000032:analysis; D012266:Ribose
chemical_list: D009702:Nucleoside Diphosphate Sugars; D009243:NAD; D010504:Periodic Acid; D011064:Poly Adenosine Diphosphate Ribose; D012266:Ribose