title: Failure of highly purified lysyl hydroxylase to hydroxylate lysyl residues in the non-helical regions of collagen.
abstract: The activity of highly purified lysyl hydroxylase towards lysyl residues within both the helical and the N-terminal non-helical telopeptide regions of chick type I collagen has been examined. The peptides alpha 1(I)-CB1 and alpha 2(I)-CB1, isolated from protocollagen following CNBr digestion and containing the N-terminal telopeptidyl lysyl residues, failed themselves to act as substrates. With protocollagen as substrate, analysis of products obtained following bacterial collagenase digestion of the reaction mixture showed that overall 37% hydroxylation of lysyl residues within the helical region of collagen had been obtained, which may be maximal. No hydroxylation, however, of the single lysyl residue in either alpha 1(I)-CB1 or alpha 2(I)-CB1, isolated following CNBr digestion of the reaction mixture, was observed, despite the known susceptibility of these residues to hydroxylation. These findings provide strong circumstantial evidence for the suggestion that a lysyl hydroxylase specific for the telopeptidyl residues and distinct from that active towards lysyl residues in the helical portion of the molecule may exist [Barnes, Constable, Morton & Royce (1974) Biochem. J. 139, 461-468].
mesh_terms: D000818:Animals; D002642:Chick Embryo; D006900:Hydroxylation; D008239:Lysine / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D011347:Procollagen / Q000378:metabolism*; D008240:Procollagen-Lysine, 2-Oxoglutarate 5-Dioxygenase / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D010446:Peptide Fragments; D011347:Procollagen; D006899:Mixed Function Oxygenases; D008240:Procollagen-Lysine, 2-Oxoglutarate 5-Dioxygenase; D008239:Lysine