Enzyme immunoassays for leukotrienes C₄ and E₄ using acetylcholinesterase

The chapter presents a study on enzyme immunoassays for leukotrienes C₄ and E₄ using acetylcholinesterase. The chapter discusses successfully developing acetylcholinesterase from Electrophorus electricus as a label for various eicosanoids, thereby providing an enzyme immunoassay with sensitivities equal to or superior to those achieved with ¹²⁵I radioactive tracers. A similar approach for LTC₄ and LTE₄ is undertaken. However, because of specific problems inherent with these molecules, a dual strategy is combined to prepare the protein-LT, conjugates necessary for the generation of antibodies and corresponding enzyme tracers. The chapter describes the development of such assays. The chapter discusses developing enzyme immunoassays for peptido-LTs by combining separate approaches to attach these haptens to macromolecules. The final strategy employed in labeling the LTs with the enzyme was arrived at as a compromise between the efficiency of the coupling reaction and preservation of the enzymatic activity. Although LTC₄ and LTE₄ may not be the relevant metabolites to evaluate the in vivo production of peptido LTs, there are a number of in vitro situations, when such assays are needed. In most systems, isolated cells only generate LTC₄, whereas in all other in vitro situations, the overall synthesis of peptido LTs can easily be estimated after enzymatic transformation of all peptido-LTs into LTE₄.