Masaaki Takami

Transphosphatidylation reaction of phosphatidylcholine to 4-methoxyphenol in water-immiscible organic solvents with immobilized phospholipase D

Immobilized phospholipase D (PLD) from Streptomyces sp. catalyzed the transfer reaction of the dipalmitoylphosphatidyl residue from 1,2-dipalmitoyl-3-sn-phosphatidylcholine (DPPC) to an aromatic hydroxy group on 4-methoxyphenol in water-immiscible organic solvents, to afford 1,2-dipalmitoyl-3-sn-phosphatidyl-4-methoxyphenol (DPP-PMP) with a 45% yield, accompanied by a trace amount of 1,2-dipalmitoyl-3-sn-phosphatidic acid sodium salt (DPPA-Na). The formation of DPP-PMP was affected by organic solvents used in the reaction. Benzene, toluene, and methylene chloride gave DPP-PMP with moderate yields but use of diethyl ether resulted in a low yield of DPP-PMP. In both ethyl acetate and water-miscible organic solvents, the transfer reaction did not take place. Immobilization of PLD was carried out by adding a 1 % volume of PLD solution to a suspension of a cation-exchange resin (Amberlite IRC-50, 5% w/v) in benzene with stirring and sonication. In a repeated batch reaction for DPP-PMP synthesis with immobilized PLD, after ten batch cycles the enzyme retained 74% of its initial activity.