The cytotoxic lipid peroxidation product, 4-hydroxy-2-nonenal specificallyinhibits decarboxylating dehydrogenases in the matrix of plant mitochondria

4-Hydroxy-2-nonenal (HNE), a cytotoxic product of lipid peroxidation, inhib its O-2 consumption by potato tuber mitochondria, 2-Oxoglutarate dehydrogen ase (OGDC), pyruvate dehydrogenase complex (PDC) (both 80% inhibited) and N AD-malic enzyme (50% inhibited) are its major targets. Mitochondrial protei ns identified by reaction with antibodies raised to lipoic acid lost this a ntigenicity following HNE treatment. These proteins were identified as acet yltransferases of PDC (78 kDa and 55 kDa), succinyltransferases of OGDC (50 kDa and 48 kDa) and glycine decarboxylase H protein (17 kDa), The signific ance of the effect of these inhibitions on the impact of lipid peroxidation and plant respiratory functions is discussed. (C) 2000 Federation of Europ ean Biochemical Societies, Published by Elsevier Science B.V. All rights re served.