Chapter 4 - Enzymatic Modification of Phospholipids by Phospholipase D

Abstract

Phospholipase D (PLD) is a useful enzyme because of its transphosphatidylation activity, which enables the head group modification of phospholipids (PLs). For this purpose, various reaction systems have been developed, including solvent–buffer biphasic, anhydrous solvent, heterogeneous phase, mixed micelle, and “green” solvent systems, which are used according to the purpose of the synthesis. PLD-mediated reactions enable the syntheses of natural and unnatural types of PLs with various functional head groups, from easily available lecithin or phosphatidylcholine. The majority of PLDs are members of the PLD superfamily, containing one or two the so-called HKD motif in their primary sequence. The superfamily members share a common core structure and, thereby, a common catalytic mechanism. Protein engineering of PLD contributes to the improvement of their activity, stability, and substrate specificity. The alteration of head group specificity enables the preparation of PLs that cannot be synthesized by wild-type PLDs, thereby expanding the applicability of this enzyme class.