Roles for iron and copper in connective tissue biosynthesis.

Both iron and copper play critical biochemical roles in the post-translational modifications of collagen and elastin. These modifications are essential to the maturation and structural integrity of these proteins. Iron functions in the hydroxylation of specific prolyl and lysyl residues in collagen, a process that must occur before the triple helix can form and be extruded from the cell. Copper functions in the oxidative deamination of specific lysyl residues in the soluble forms of both elastin and collagen. This process is essential for crosslink formation and the structural integrity of these proteins. While there is no evidence that nutritional iron deficiency results in connective tissue pathology, copper deficiency impairs crosslink formation and results in gross pathology of bones, lungs and the cardiovascular system of many animal species.