title: The catalytic mechanism of the hydroxylation reaction of peptidyl proline and lysine does not require protein disulphide-isomerase activity.
abstract: Prolyl 4-hydroxylase, an alpha 2 beta 2 tetramer, catalyses the formation of 4-hydroxyproline in collagens. The beta subunit is known to be identical with the enzyme protein disulphide-isomerase and to possess disulphide-isomerase activity even when present in the prolyl 4-hydroxylase tetramer. We here report that lysyl hydroxylase, a homodimer, and algal prolyl 4-hydroxylase, a monomer, do not contain detectable protein disulphide-isomerase activity. Since the hydroxylase reaction mechanisms are similar, the data suggest that the protein disulphide-isomerase activity of the vertebrate prolyl 4-hydroxylase beta subunit is unlikely to be involved in the catalytic mechanism of the hydroxylation reaction.
authors.affiliation: Collagen Research Unit, University of Oulu, Finland.
authors.forename: R
authors.initials: R
authors.lastname: Myllylä
authors.forename: D D
authors.initials: DD
authors.lastname: Kaska
authors.forename: K I
authors.initials: KI
authors.lastname: Kivirikko
mesh_terms: D000818:Animals; D002384:Catalysis; D002642:Chick Embryo; D002696:Chlamydomonas / Q000201:enzymology; D006900:Hydroxylation; D007535:Isomerases / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism; D046911:Macromolecular Substances; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D008970:Molecular Weight; D008240:Procollagen-Lysine, 2-Oxoglutarate 5-Dioxygenase / Q000378:metabolism*; D011393:Procollagen-Proline Dioxygenase / Q000378:metabolism*; D011392:Proline / Q000378:metabolism; D019704:Protein Disulfide-Isomerases
chemical_list: D046911:Macromolecular Substances; D011392:Proline; D006899:Mixed Function Oxygenases; D011393:Procollagen-Proline Dioxygenase; D008240:Procollagen-Lysine, 2-Oxoglutarate 5-Dioxygenase; D007535:Isomerases; D019704:Protein Disulfide-Isomerases; D008239:Lysine