Cloning and Characterization of a Novel Human Lysyl

WereporttheisolationandcharacterizationofcDNAclones for a novel isoform of lysyl hydroxylase (lysylhydroxylase2),aposttranslationalenzymeofcollagenbiosynthesis.Theopenreadingframepredictedapro-tein of 737 amino acids, including an amino-terminalsignal peptide. The amino acid sequence has overallsimilarity of over 75% to the lysyl hydroxylase (lysylhydroxylase1)characterizedearlier.Thissimilarityisevenhigherinthecarboxyl-terminalendofthemole-cules.Lysylhydroxylase2containsninecysteineresi-dues,whichareconservedinlysylhydroxylase1.Fur-thermore, the conserved histidines and aspartateresidues required for lysyl hydroxylase activity arepresentinthesequence.Northernanalysisidentifiedatranscriptof4.2kilobases,whichwashighlyexpressedinpancreasandmuscletissues.ExpressionofcDNAininsectcellsusingabaculovirusvectoryieldedproteinswith lysyl hydroxylase activity and an antiserumagainstasyntheticpeptideofthededucedaminoacidsequencerecognizedproteinswithmolecularweightsof88and97kDainhomogenatesofthetransfectedcells.