[MIM*153455] an enzyme, which requires Cu2+ and O2, that oxidizes certain lysyl residues in collagen to allysyl residues and hydroxylysyl residues to hydroxyallysyl residues; this is a required step for the cross-linking (via aldol condensations and through Amadori rearrangements) of collagen strands; a lower activity of this enzyme is associated with occipital horn syndrome.