lysyl hydroxylase

ly·syl hy·drox·y·lase (liґsəl hi-drokґsə-lās) an enzyme of the oxidoreductase class that catalyzes the hydroxylation of specific lysine residues in nascent procollagen chains; the hydroxylysine residues act as sites of attachment for disaccharide prosthetic groups and are involved in the formation of strong interchain crosslinks in collagen. The enzyme requires Fe²⁺, ascorbate, and α-ketoglutarate for activity. Deficiency of enzyme activity, an autosomal recessive trait, results in the kyphoscoliosis type of Ehlers-Danlos syndrome. In EC nomenclature, called procollagen-lysine 5-dioxygenase.