title: Inhibition of prolyl hydroxylase by poly(ADP-ribose) and phosphoribosyl-AMP. Possible role of ADP-ribosylation in intracellular prolyl hydroxylase regulation.
abstract: Poly(ADP-ribose) prepared by incubating NAD+ with rat liver nuclei inhibited the hydroxylation reaction catalyzed by purified prolyl hydroxylase (proline,2-oxoglutarate dioxygenase, EC 1.14.11.2) in vitro. Near complete inhibition of the enzyme was seen in the presence of 6 nM (ADP-Rib)18 with a Ki(app) of 1.5 nM. The monomer unit of poly(ADP-ribose), adenosine diphosphoribose (ADP-Rib), was found to be a weak inhibitor. On the other hand, poly(ADP-ribose)-derived phosphoribosyl-AMP (PRib-AMP) and its dephosphorylated product, ribosyl-ribosyl-adenine (Rib-RibA), inhibited the enzyme in nanomolar concentrations (Ki(app) 16.25 nM). The order of inhibition was (ADP-Rib)18 greater than PRib-AMP, Rib-RibA much greater than ADP-Rib. These results suggested that the 1"----2' ribosyl-ribosyl moiety in these compounds was involved in the inhibition of the enzyme. The possibility that intracellular prolyl hydroxylase is regulated by the involvement of ADP-ribosylation reactions was examined in confluent cultures of skin fibroblast treated with 20 mM lactate. The activity of prolyl hydroxylase was stimulated by 145% over that of untreated cultures. In the lactate-treated cells, the level of NAD+ was lowered and the total ADP-ribosylation of cellular proteins reduced by 40%. These observations imply that the lactate-induced activation of cellular prolyl hydroxylase is mediated by a reduction in ADP-ribosylation and that the synthesis and degradation of ADP-ribose moiety(ies) may possibly regulate prolyl hydroxylase activity in vivo.
authors.affiliation: Department of Stomatology, School of Dentistry, University of California, San Francisco 94143.
authors.forename: M Z
authors.initials: MZ
authors.lastname: Hussain
authors.forename: Q P
authors.initials: QP
authors.lastname: Ghani
authors.forename: T K
authors.initials: TK
authors.lastname: Hunt
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000246:Adenosine Diphosphate Ribose / Q000494:pharmacology; D000249:Adenosine Monophosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D002642:Chick Embryo; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology; D006900:Hydroxylation; D007773:Lactates / Q000494:pharmacology; D019344:Lactic Acid; D008099:Liver / Q000378:metabolism; D006899:Mixed Function Oxygenases; D009243:NAD / Q000378:metabolism; D009702:Nucleoside Diphosphate Sugars / Q000494:pharmacology*; D043264:Phosphodiesterase I; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D011064:Poly Adenosine Diphosphate Ribose / Q000494:pharmacology*; D011347:Procollagen / Q000378:metabolism; D011393:Procollagen-Proline Dioxygenase / Q000037:antagonists & inhibitors*; D011817:Rabbits; D051381:Rats
chemical_list: D007773:Lactates; D009702:Nucleoside Diphosphate Sugars; D011347:Procollagen; D009243:NAD; C016664:2'-(5''-phosphoribosyl)-5'-adenosine monophosphate; D000246:Adenosine Diphosphate Ribose; D011064:Poly Adenosine Diphosphate Ribose; C059700:ribosyl-ribosyladenine; D019344:Lactic Acid; D000249:Adenosine Monophosphate; D006899:Mixed Function Oxygenases; D011393:Procollagen-Proline Dioxygenase; D010727:Phosphoric Diester Hydrolases; D043264:Phosphodiesterase I; D000241:Adenosine