Palmitoylcarnitine is a well-known intermediate in mitochondrial fatty acid oxidation. Less known are its properties as a snrfactant, with a capacity to solubilize biological membranes similar to that of many synthetic detergents used in the biochemical laboratory. Some of the physico-chemical properties of palmitoylcarnitine may help to explain the need for coenzyme A-carnitine-coenzyme A acyl exchange during mitochondrial fatty acid import. The amphiphilic character of palmitoylcarnitine may also explain its proposed involvement in the pathogenesis of myocardial ischemia.

The ability of fatty acyl-CoA's and fatty acylcarnitines to penetrate phospholipid monolayers was comparatively studied, in view of the important role of both kinds of derivatives in fatty acid transport across mitochondrial membranes. The interaction occurs predominantly through hydrophobic forces. Acylcarnitines penetrate phospholipid monolayers more strongly than acyl-CoAs; in addition the former show a positive cooperativity when they bind to the interface. These properties would facilitate membrane transfer of fatty acylcarnitines over that of their CoA homologues.physical penetration of at least part of the amphiphile into the film [6-1 I].In our studies of acyl-CoA and acylcarnitine penetration, the hydrocarbon chain length of both phospholipids and fatty acyl derivatives has been changed in order to study the hydrophobic components of the interaction; the polar group of phospholipids has also been changed in order to identify electrostatic interactions. Fatty acylcarnitines appear to interact positively with the lipid monolayer, unlike their homologous coenzyme A derivatives.

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