Modulation of enzymatic PS synthesis by liposome membrane composition.
Phosphatidylserine (PS) is a phospholipid known to exert important physiological roles in humans. However, this phospholipid (PL) is poorly available as a natural source and hardly produced by the chemical route. In this work, PS was obtained by transphosphatidylation using phospholipase D (PLD) and PL self-assembled into liposomes as the substrates. The aim was to better understand how the liposome membrane composition could modulate PS yield. Three lecithins were used as PL substrates, one originated from a marine source providing a high amount of n-3 polyunsaturated fatty acids, and two issued from soya differing in their phosphatidylcholine (PC) content. Different parameters such as Ca(2+) content, enzyme and L-serine concentrations modulated PS synthesis. The presence of Ca(2+) increased PS conversion yield. The alcohol acceptor (L-serine) concentration positively acted on PL conversion, by governing the equilibrium between transphosphatidylation and hydrolysis. Beside these specific reaction conditions, it was demonstrated that the membrane composition of the liposomes modulated PS synthesis. A direct correlation between PS accumulation and the amount of cholesterol or α-tocopherol incorporated into the soya lecithins was observed. This result was interpreted in terms of "head" spacers promoting PLD transphosphatidylation. On the whole, this work provided key parameters for the formulation of liposomes using enzymatic PLD technology, to produce lecithins enriched in different proportions of PS and esterified with various types of fatty acids depending on the initial lecithin source.
['Pinsolle|Alexandre|A|', 'Roy|Philippe|P|', 'Cansell|Maud|M|']
D059001:Aquatic Organisms D002122:Calcium Chloride D005227:Fatty Acids D054709:Lecithins D008081:Liposomes D010713:Phosphatidylcholines D010714:Phosphatidylethanolamines D010718:Phosphatidylserines D010739:Phospholipase D D013997:Time Factors
Liposomes Phosphatidylserine Transphosphatidylation Phospholipase D Lecithin