Modulation of lipoxygenase activity in linoleic acid/ phosphatidylcholine monolayers and bilayers

MEDINA, A.V.; BOUCHET, A.; NAZARENO M. A.; DISALVO, A.

Carlos Paz, Córdoba

Simposio; XLII Reunión Anual de la Sociedad Argentina de Biofísica. SAB 2013; 2013

SAB

Plant LOX are members of a class of nonheme iron containing dioxygenases that catalyze the addition of molecular oxygen to fatty acids containing a cis, cis-1,4- pentadiene system to give an unsaturated fatty acid hydroperoxide as a first of several secondary products. It has been found that the enzyme activity in micelles can be modulated by the ionic nature of surfactants and the presence of water. The main objective was to study the modulation of LOX activity in lipid monolayers composed by phosphatidylcholine and linoleic acid (LA), in order to analyze the effect of the lipid surface on the catalytic activity. Subsequent additions of the lipid mixture were added to the interphase to reach a desired pressure. After equilibration the LOX was added to the subphase. Upon injection of the enzyme the surface pressure increases three fold in DSPC: LA monolayer in comparison with the control DSPC:SA monolayers. Samples to determine oxidation products were extracted. LOX products appears only in DSPC:LA monolayer, suggesting that the differences in surface pressure increase in due to a modification of the chemical species in the lipid phase.