A single-step procedure for the synthesis of photoreactive and radioactive glycerolipids.

A single-step procedure was developed for the incorporation of iodoazide into oleic acid, triolein, and phosphatidylcholine. Iodoazide was generated using $[^{125}I]$ iodomonochloride and sodium azide that was found to add stereospecifically in a variety of olefins. Photoreactive and radiolabeled triacylglycerol and phosphatidylcholine were synthesized with a moderate yield and high specific activity. The stability of both the radiolabel and the photoreactive group was studied under ultraviolet light under aqueous as well as anhydrous conditions. These synthesized analogs act as substrates in the dark, and as irreversible inhibitors under ultraviolet irradiation for the target hydrolytic enzymes. The synthesized radiolabeled photoprobes were subsequently used to label lipase and phospholipase $A_2$. The results highlighted the efficiency and rapidity of the method and its potential application in the study of lipid-metabolizing enzymes.