Abstract

A competitive enzyme linked immunosorbent assay (ELISA) for the quantification of butyrylcholinesterase (BChE) (EC 3 118) substance concentration in avian serum samples is described. The assay is based on polyclonal (rabbit) anti pigeon BChE coupled with biotin. The binding of the biotinylated antibody to immobilized antigen is competitively inhibited by an added standard or test antigen, and the amount of label bound antibody is inversely related to the concentration of antigen. The assay yields positive reactions with as little as 0.15 ng/ml of antigen. The assay was employed to investigate changes in the quantities of BChE in avian serum, following exposure to organophosphorus insecticides, which are not measured by the. Standard bioassay of this enzyme. The applicability of the assay to metabolic and toxicological studies is demonstrated, and the determination of the specific activity of BChE is recommended as a rational diagnostic tool after measurement of both activity and concentration of the enzyme.