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  • Oxidizability of cardiac cardiolipin in Triton X-100 micelles as determined by using a Clark electrode.

Oxidizability of cardiac cardiolipin in Triton X-100 micelles as determined by using a Clark electrode.

Chemistry and physics of lipids (2009-11-03)
Vitaly Roginsky
ABSTRACT

The kinetics of the chain free-radical oxidation of cardiolipin (CL), a unique phospholipid containing four linoleate moieties, have been studied for the first time. The technique based on monitoring oxygen consumption by using a Clark electrode was applied to determine the oxidizability of CL during its initiated oxidation in aqueous Triton X-100 micelles in 50mM phosphate buffer, pH 7.40, at 37 degrees C. The oxidizability was characterized by the k(2)/(sqrt[2k(3)]) ratio, where k(2) and k(3) are the rate constants for the reaction of chain propagation (LO(2)+LH-->LOOH+L) and chain termination (2LO(2)-->products), correspondingly. The oxidizability of CL (in M(-0.5)s(-0.5)) was found to be of 0.62+/-0.07 (calculated on the basis of a single linoleate fragment) that is twice as much than the oxidizability of methyl linoleate (0.32+/-0.04) determined in the same testing systems. It has been shown that the increase in k(2)/(sqrt[2k(3)]) by a factor of two when going from the oxidation of ML to that of CL is almost completely determined by the increase in k(2).

MATERIALS
Product Number
Brand
Product Description

Supelco
Methyl linolelaidate, analytical standard
Supelco
trans-9,12-Octadecadienoic acid methyl ester, certified reference material, 10 mg/mL in heptane
Supelco
Methyl linoleate, analytical standard
Sigma-Aldrich
Methyl linoleate, ≥98% (GC)
Supelco
cis-9,cis-12-Octadecadienoic acid methyl ester, certified reference material, 10 mg/mL in heptane