Development of a peptide antibody specific to human glutathione S-transferase alpha 4-4 (hGSTA4-4) reveals preferential localization in human liver mitochondria

The reactive cellular products generated during the peroxidation of membran e lipids have been implicated as causative agents in a variety of degenerat ive diseases and aging. In particular, 4-hydroxynon-2-enal (4HNE) is among the most of the produced during lipid peroxidation. In humans and rodent sp ecies, the alpha 4 subclass of glutathione S-transferases (mGSTA4-4, rGSTA4 -4, hGST-5.8, and hGSTA4-4) exhibits uniquely high glutathione conjugation activity toward 4HNE and other hydroxyalkenals. In human liver, hGSTA4-4-me diated 4HNE conjugation appears to represent the high-affinity pathway for 4HNE detoxification. In the present study, a highly specific polyclonal ant ibody was developed against hGSTA4-4. Western blotting analysis of human li ver subcellular fractions as well as N-terminal sequencing revealed that hG STA4-4 was localized to mitochondrial fractions, but was not detected in cy tosolic fractions. Our results provide evidence that in adult liver, hGSTA4 -4 is specifically targeted to the mitochondrion to the apparent exclusion of the cytosol. Targeting of hGSTA4-4 to the mitochondrion holds implicatio ns for degenerative diseases associated with oxidative stress that arise fr om aerobic respiration. (C) 2001 Academic Press.