NEW FLUORESCENT GLYCEROLIPIDS FOR A DUAL-WAVELENGTH ASSAY OF LIPASE ACTIVITY AND STEREOSELECTIVITY

A new type of fluorogenic alkyldiacyl glycerols was synthesized and us ed as fluorogenic substrates for the analysis of lipase activities and stereoselectivities. These compounds contain pyrene or perylene as a fluorophore and the trinitrophenylamino-(TNP) residue as a quencher. B oth substituents an covalently bound to the omega-ends of the sn-2 and sn-1(3) acyl chains, respectively. Upon glycerolipid hydrolysis, the residues are separated from each other thus allowing determination of lipase activity from the continuous increase in fluorescence intensity which is caused by dequenching. Mixtures of enantiomeric fluorogenic alkyldiacyl glycerols, selectively labeled with pyrene or perylene as fluorophores, can be used for a dual-wavelength 'stereoassay' of lipas es. Since absorption and emission maxima of both labels are clearly se parated, hydrolysis of the respective enantiomeric substrates can be d istinguished simultaneously, and the difference in their rates of hydr olysis can be taken as a parameter for the stereopreference of a lipas e.