A comparison of phospholipid degradation by oxidation and hydrolysis during the mitochondrial permeability transition

• Published in: Archives of biochemistry and biophysics Vol. 285; no. 2; pp. 252 - 260
• Main Authors: Erdahl, Warren L., Krebsbach, Randy J., Pfeiffer, Douglas R.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.03.1991; Elsevier
• Subjects: Animals; Biological and medical sciences; Cell structures and functions; Chromatography, High Pressure Liquid; Ferrous Compounds - pharmacology; Fundamental and applied biological sciences. Psychology; Hydrolysis; Kinetics; Lipid Peroxidation; Magnesium - metabolism; Male; Malondialdehyde - metabolism; membrane permeability; mitochondria; Mitochondria and cell respiration; Mitochondria, Liver - drug effects; Mitochondria, Liver - metabolism; Mitochondrial Swelling; Molecular and cellular biology; Oxidation-Reduction; Permeability; Peroxides - pharmacology; Phosphatidylethanolamines - metabolism; Phospholipids - metabolism; Rats; Rats, Inbred Strains; tert-Butylhydroperoxide; Hydrolysis; Vertebrata; Mitochondria; Mammalia; Rat; Induction; Rodentia; Phospholipid; Transition; Permeability; Comparative study; Peroxidation
• ISSN: 0003-9861; 1096-0384
• DOI: 10.1016/0003-9861(91)90357-O

The peroxidation and hydrolysis of mitochondrial phospholipids has been examined under conditions which are referable to induction of the permeability transition by t-butylhydroperoxide. Over a 30-min time course, the peroxide causes formation of 0.3 nmol/mg protein of malondialdehyde. This value is little effected by Ca 2+, Sr 2+, or Mn 2+ but is increased approximately fivefold by Fe 2+. The latter cation, but not the others, results in malondialdehyde formation in the absence of added peroxide. Partially oxidized phosphatidylethanolamine is present in normal mitochondria and is increased by ∼50% following t-butylhydroperoxide treatment; however, the amounts observed are in the range of 0.4–0.6 mol% of total phosphatidylethanolamine. The minor degradation by peroxidation is in contrast to ∼2.5 mol% degradation which occurs by hydrolysis. This degree of hydrolysis is accompanied by mitochondrial swelling and Mg 2+ release, while a comparable level of peroxidation (malondialdehyde formation) is not. It is concluded that induction of the permeability transition by t-butylhydroperoxide does not represent damage to the membrane lipid phase caused by peroxidation. It is possible, however, that peroxidation accelerates the accumulation of phospholipid hydrolysis products and is thereby a factor which favors the transition.