Also acts on protein 5-hydroxylysine. This enzyme catalyses the final known enzymic step required for collagen and elastin cross-linking in the biosynthesis of normal mature extracellular matrices . These reactions play an important role for the development, elasticity and extensibility of connective tissue. The enzyme is also active on free amines, such as cadaverine or benzylamine [4,5]. Some isoforms can also use [protein]-N(6)-acetyl-L-lysine as substrate deacetamidating the substrate .