Enzyme Immunoassay of Human Cholinesterase (EC 3.1.1.8) Comparison of Immunoreactive Substance Concentration with Catalytic Activity Concentration in Randomly Selected Serum Samples from Healthy Individuals

We developed an enzyme immunoassay (ELISA) for quantitation of plasma cholinesterase substance concentrations in native plasma or serum samples. The ELISA assay is based on polyclonal (rabbit) antihuman cholinesterase and a highly specific monoclonal (mouse) antibody, with a commercially available peroxidase-conjugated (rabbit) antibody directed against mouse immunoglobulins as the signal carrier. The detected serum cholinesterase substance concentrations (mean: 4.51 mg/l, SD: 0.90 mg/l) in randomly selected serum samples from 33 healthy individuals were closely and linearly related to the corresponding catalytic activity concentrations.