PHYSIOLOGICAL-ROLE OF GLUTATHIONE S-TRANSFERASES IN PROTECTION MECHANISMS AGAINST LIPID-PEROXIDATION - A COMMENTARY

A group of structurally and functionally related glutathione S-transfe rase isoenzymes which show relatively high activity towards 4-hydroxya lkenals and can catalyze glutathione mediated reduction of lipid hydro peroxides is identified in mammalian and avian tissues. The isoenzymes within this group show high degree of sequence homology, and interspe cies immunological and kinetic similarities, but are immunologically a nd kinetically distinct from the alpha, mu, and pi-classes of GSTs. St udies so far carried with rats indicate that these enzymes are present in high concentration in the smooth muscle cells of aorta where they can be induced by stimuli causing enhanced lipid peroxidation. Possibl e physiological role of this group of GSTs in the protection mechanism s against the toxicity of 4-hydroxyalkenals and the role of the cation ic a-class GSTs in reduction of phospholipid hydroperoxides is discuss ed.