LIPOXYGENASE ACTIVITY IN RAT DERMIS AND EPIDERMIS - PARTIAL-PURIFICATION AND CHARACTERIZATION

Lipoxygenase (LOX) activity in epidermis and dermis was distributed among microsomal and cytosolic fractions. The main products of polyunsaturated fatty acid metabolism were 12-hydroperoxy-cis-5,8,14, trans-10-eicosatetraenoic acid (12-HPETE), 15-hydroperoxycis-5,8,11, trans-13-eicosatetraenoic acid (15-HPETE) and 13-hydroxy-cis-9, trans-11-octadecadienoic acid (13-HOD). Enzyme activities were isolated from rat dermis and epidermis by ammonium sulphate precipitation, hydrophobic chromatography and gel filtration. In the dermis, activity was found at a molecular mass of 68 kDa, a pl of 4.6 and a K-m of 50 mu M. This activity was inhibited by known LOX inhibitors. The main reaction products indicated that this was 15-LOX. In the epidermis, activity was found in a fraction with a molecular mass of 68 kDa, a pl of 4.6 and a K-m of 80 mu M. Activity was inhibited by known LOX inhibitors whereas the reaction products indicated that this was 12-LOX. LOX activity in rat skin may involve one enzyme with dual regional specificities or may comprise two different enzymes.