Localization of corneal superoxide dismutase by biochemical and histocytochemical techniques.

Superoxide dismutase activity is found in the cornea of rats, dogs, rabbits and humans. A superoxide dismutase identical to the Cu-Zn enzyme is identified by biochemical and immunochemical methods in the corneal epithelium and endothelium in relative high abundance (90-100 U mg-1 protein). The enzyme quantities detected by radioimmune assay and bioactivity assay are similar, giving evidence that the enzyme present is biologically functional. Immunohistochemical techniques demonstrate the association of the enzyme with the cytoplasm of these layers. Soluble protein extracts of corneal stroma exhibit weak apparent superoxide dismutase activity which is found to be mainly due to copper associated with serum albumin.