Characterization of the Copper-binding of Phosphatidyl Ethanolamine Emulsion in Its Rapid Autoxidation

Abstract

The copper-catalyzed O₂ uptake of phosphatidyl ethanolamine emulsion was measured by the Warburg's manometry. When EDTA (ethylenediamine, tetraacetic acid) was added to the emulsion, EDTA inactivated copper stoichiometrically in molar ratio of 1:1. Monoethanolamine, α-glycerophosphoric acid, O-phosphoryl ethanolamine, and glyceryl phosphoryl ethanolamine were not effective. IDA (iminodiacetic acid) depressed the O₂ uptake of phosphatidyl ethanolamine and the affinity of phosphatidyl ethanolamine to copper was estimated as one-thirtieth that of IDA. The emusion diluted with Tween 20 showed lower affinity to copper of one-tenth of the original emulsion. At the interface of the phosphatidyl ethanolamine, its high affinity to copper like chelate effect is assumed.