title: Photoaffinity labelling of the 2-oxoglutarate binding site of prolyl 4-hydroxylase with 5-azidopyridine-2-carboxylic acid.
abstract: The synthesis of the photoaffinity label 5-azidopyridine-2-carboxylic acid is described. The 2-oxoglutarate analogue photoaffinity label is a competitive inhibitor with respect to 2-oxoglutarate with a Ki value of 9 X 10(-3) M. Upon ultraviolet irradiation, 5-azidopyridine-2-carboxylic acid inactivated prolyl 4-hydroxylase irreversibly by up to 50%. The extent of inactivation depended on the 5-azidopyridine-2-carboxylic acid concentration and the irradiation time. Inactivation was prevented in the presence of an excess of 2-oxoglutarate. It is concluded that the 5-azidopyridine-2-carboxylic acid became covalently bound to the alpha subunit of prolyl 4-hydroxylase, as the alpha subunit of the photoaffinity labelled enzyme had a decreased electrophoretic mobility in polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate.
mesh_terms: D000345:Affinity Labels / Q000138:chemical synthesis* / Q000494:pharmacology; D001386:Azides / Q000138:chemical synthesis* / Q000494:pharmacology; D001665:Binding Sites; D007656:Ketoglutaric Acids / Q000378:metabolism; D010777:Photochemistry; D010848:Picolinic Acids / Q000138:chemical synthesis* / Q000494:pharmacology; D011393:Procollagen-Proline Dioxygenase / Q000037:antagonists & inhibitors; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000345:Affinity Labels; D001386:Azides; D007656:Ketoglutaric Acids; D010848:Picolinic Acids; C051862:5-azidopyridine-2-carboxylic acid; D011393:Procollagen-Proline Dioxygenase