Synthesis of photoreactive phosphatidylethanolamine and its interaction with phospholipase A2.

A photoreactive derivative of phosphatidylethanolamine, N-(4-azidobenzoyl)phosphatidylethanolamine (AB-PE), was synthesized by acylation of phosphatidylethanolamine with an N-hydroxysuccinimide ester of 4-azidobenzoic acid. The substantial photosensitivity exhibited by AB-PE correlated with a marked decrease in the absorption spectra of the compound. The compound proved sensitive to lipase and phospholipase A2 hydrolysis but resistant to phospholipase C and D activities. Photolysis of a sonicated dispersion of AB-PE containing phospholipase A2 resulted in irreversible inhibition of the enzyme. Addition of natural phosphatidylethanolamine provided protection against photoinactivation.