title: The stereochemical course of nucleotidyl transfer catalysed by NAD pyrophosphorylase.
abstract: NAD pyrophosphorylase catalyses nucleotidyl transfer from adenosine (R)-5'-[alpha-17O]triphosphate to nicotinamide mononucleotide with inversion of configuration at the alpha-P giving (S)-[17O]NAD+. The simplest interpretation of this observation is that the adenylyl group is transferred directly from ATP to the co-substrate by an 'in line' mechanism. It is also shown that snake venom phosphodiesterase hydrolyses NAD+ regio-specifically at the adenylyl terminus of the pyrophosphate bond.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002384:Catalysis; D055598:Chemical Phenomena; D002621:Chemistry; D008099:Liver / Q000201:enzymology; D009682:Magnetic Resonance Spectroscopy; D009243:NAD / Q000378:metabolism; D009612:Nicotinamide-Nucleotide Adenylyltransferase / Q000502:physiology*; D009713:Nucleotidyltransferases / Q000502:physiology*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D012910:Snake Venoms / Q000032:analysis; D013237:Stereoisomerism; D013379:Substrate Specificity; D013552:Swine
chemical_list: D012910:Snake Venoms; D009243:NAD; D000255:Adenosine Triphosphate; D009713:Nucleotidyltransferases; D009612:Nicotinamide-Nucleotide Adenylyltransferase; D010727:Phosphoric Diester Hydrolases