Methyl-branched glycerophosphocholines: monolayer disorder and its effect on the rate of phospholipase A2 catalyzed hydrolysis

Abstract

Phospholipase A₂ catalyzes the cleavage of the sn-2 ester bond of phospholipids. Both the capability to bind to the surface of a phospholipid aggregate and the catalytic turnover rate are highly dependent on the physical state and the molecular packing of the aggregated substrate. Methyl-branched glycerophosphocholines (PCs) were studied in order to evaluate the influence of short-chain branching on monolayer packing properties and its effect on the hydrolysis reaction. The diester PCs were cleaved at a higher rate than the plasmalogen-analogue ether–ester compounds. Branching in the sn-2 chain has a stronger effect than in the non-cleaved chain. The correlation of the ill-ordered monolayer structure with the reduced reaction yield is discussed.