MICROSOMAL ALDEHYDE DEHYDROGENASE OR ITS CROSS-REACTING PROTEIN EXISTS IN OUTER MITOCHONDRIAL-MEMBRANES AND PEROXISOMAL MEMBRANES IN RAT-LIVER

We investigated the subcellular distribution of microsomal aldehyde de hydrogenase (msALDH) in rat liver and revealed by the immunoblotting m ethod that msALDH or a cross-reacting 54-kDa protein(s) exists in the outer mitochondrial membranes and peroxisomes. Anti-msALDH antibody ma rkedly inhibited the decanal aldehyde dehydrogenase activity of the ou ter mitochondrial membranes as well as that of the microsomes. Immunog old electron microscopic observations showed that gold particles are l ocalized over the ER, outer mitochondrial membranes and peroxisomal me mbranes. These results suggest that msALDH or its crossreacting relate d protein is distributed not only in the ER membranes but also in the mitochondrial outer membranes and peroxisomal membranes.