MEASUREMENT OF PHOSPHOLIPID OXIDATION IN MODEL MEMBRANES BY DETERMINATION OF OXYGEN-CONSUMPTION WITH A SEMIAUTOMATIC POLAROGRAPHIC METHOD

Among methods for studying lipid oxidation, the measurement of oxygen consumption is rarely used, probably because it is difficult to proces s the data obtained as traces on paper recorder. With the described sy stem, the data obtained from two oxygen meters are collected and analy sed to study catalysed phospholipid oxidation in liposomes. Oxygen upt ake and rate of oxygen consumption at different times, maximum rate an d apparent pseudo first order constants in fast and slow stages of the reaction are easily obtained with good reproducibility on homogeneous series of fresh phospholipids. When the phospholipids are already oxi dised, the shape of the curve is modified as well as the calculated pa rameters. As compared to PIPES buffer, phospholipid oxidation is inhib ited by cacodylate buffer in the first stages of the reaction, and enh anced later on. The antioxidant effects of alpha-tocopherol and BHT ar e clearly shown.