Probing the role of C-1 ester group in Naja naja phospholipase A(2)-phospholipid interactions using butanetriol-containing phosphatidylcholine analogues

To understand the role of the ester moiety of the sn-1 acyl chain in phosph olipase A(2)-glycerophospholipid interactions, we introduced an additional methylene residue between the glycerol C1 and C2 carbon atoms of phosphatid ylcholines, and then studied the kinetics of hydrolysis and the binding of such butanetriol-containing phospholipids with Naja naja phospholipase A(2) . Hydrolysis was monitored by using phospholipids containing a NBD-labelled sn-2 acyl chain and binding was ascertained by measuring the protein trypt ophan fluorescence. The hydrolysis of butanetriol-containing phospholipids was invariably slower than that of the glycerol-containing phospholipids. I n addition, the enzyme binding with the substrate was markedly decreased up on replacing the glycerol residue with the 1,3,4-butanetriol moiety in phos phatidylcholines. These results have been interpreted to suggest that the s n-1 ester group in glycerophospholipids could play an important role in pho spholipase A(2)-phospholipid interactions.