Abstract: | A system for quantitative determinations of human thyroid peroxidase (TPO) in biological fluids has been obtained, based on the use of enzyme-linked immunosorbent assay. Immunochemical properties of TPO were studied under variable conditions, and a new method for isolating the protein from microsomes, mitochondria, and cytosol of thyroid glands of patients with diverse thyroid diseases was developed. The procedure involves solubilization of subcellular fractions with detergents, their sonication, two sequential runs of chromatography (on sorbents with immolbilized monoclonal antibodies against TPO and goat anti-human immunoglobulin antibodies), treatment with ribonuclease, and dialysis. Highly purified preparations of intact TPO and a product of its limited trypsinolysis are expected to be used as research tools and components of high-sensitivity immunoassays. |