Age-related mitochondrial lipoperoxidation in human skin.

Mitochondria were isolated from the epidermis of human subjects of different ages by a procedure that included pretreatment of the tissue with bacterial protease before homogenization. That epidermal mitochondria catalyze enzymatic lipid peroxidation in the presence of NADPH and chelated iron (ADP-Fe3+) is indicated by the production of malonaldehyde. The process does not appear to be influenced by age, and it is strongly enhanced in preparations containing a small amount of melanin.