FEASIBILITY OF AN IMMUNOASSAY FOR MEVALONOLACTONE

Mevalonic acid is a key intermediate in a broad spectrum of cellular b iological processes and their regulation. Availability of a rapid, sen sitive and accurate method for its assay would be highly useful. There fore, the feasibility of developing an immunoassay for mevalonic acid in biological samples was explored. The strategy employed was to synth esize several racemic haptens structurally resembling R-mevalonolacton e, the cyclic form of mevalonic acid present at lower pH and presumed to be more antigenic. Two of these haptens were coupled to keyhole lim pet hemocyanin, and the resulting conjugates were used successfully to generate antibodies in rabbits. The first antiserum bound to R,S-meva lonolactone much more effectively at pH 4.0 than at pH 6.0, consistent with the structural resemblance of the haptens to the lactone form. T his antiserum also bound the free hapten from which it was generated a nd two others of different structure with comparable effectiveness, an d slightly better than it bound R,S-mevalonolactone at pH 4.0. Similar results were obtained with the antiserum to the second hapten. The bi nding of either antiserum to the natural enantiomer, R-mevalonolactone , was 20 times weaker than to R,S-mevalonolactone, suggesting that the nonbiological enantiomer was more antigenic. Nevertheless, the result s demonstrate that an immunochemical approach to accurate quantitation of mevalonic acid in biological samples is feasible. (C) 1997 Elsevie r Science Ltd.