Phospholipases as Synthetic Catalysts

Natural phospholipids can be completely modified with a group of hydrolytic enzymes found in living organisms. Phospholipase A₁, phospholipase A₂, and 1,3-specific lipases are hydrolases which can selectively cleave the ester bonds at position sn1 and sn2. The compounds of partial hydrolysis can be reacylated chemically. Each of the compounds obtained can then be modified with the very efficient phospholipase D which can effect polar head substitution in the presence of an alcohol as a phosphoryl acceptor. The enzymes from bacterial sources are readily available from culture broth and are highly selective. Phospholipase C can be used to obtain diacylglycerol and organic phosphates as hydrolysis products. The sequential use of the latter enzymes allows the preparation of organic diphosphates. The factors affecting the specificity and selectivity of these enzymes is discussed.