Interaction of thyroid peroxidase with concanavalin A covalently coupled to agarose

• Published in: The Journal of biological chemistry Vol. 252; no. 4; pp. 1264 - 1271
• Main Authors: Neary, J.T, Koepsell, D, Davidson, B, Armstrong, A, Strout, H.V, Soodak, M, Maloof, F
• Format: Journal Article
• Language: English
• Published: United States American Society for Biochemistry and Molecular Biology 25.02.1977
• Subjects: Animals; Binding, Competitive; Calcium - pharmacology; Chromatography, Affinity; Concanavalin A; Enzyme Activation - drug effects; Hexoses - pharmacology; Hydrogen-Ion Concentration; Iodide Peroxidase - isolation & purification; Iodide Peroxidase - metabolism; Kinetics; Manganese - pharmacology; Methylglucosides - pharmacology; Methylmannosides - pharmacology; Peroxidases - metabolism; Protein Binding; Swine; Thyroid Gland - enzymology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(17)40650-8

We have investigated the interaction between concanavalin A-agarose (Con A-agarose) and thyroid peroxidase, an integral membrane protein found in the 105,000 X g, 1-h particulate fraction of thyroid tissue. An intact form of porcine thyroid peroxidase was obtained by solubilization with the nonionic detergent Triton X-100 and two fragmented, hydrophilic forms of the enzyme were prepared by trypsin treatment of the membrane. The three types of thyroid peroxidase bind to Con A-agarose and can be eluted with alpha-methyl-D-mannoside. The alpha-methyl-D-mannoside eluate of the most purified thyroid peroxidase preparation has been analyzed by polyacrylamide gel electrophoresis. Peroxidase activity corresponds with a glycoprotein band. The binding of thyroid peroxidase to Con A-agarose can be inhibited by sugars in the following order: alpha-methyl-D-mannoside greater than D-mannose greater than alpha-methyl-D-glucoside greater than D-glucose greater than D-galactose. This order of specificity is typical of Con A-sugar interactions. Furthermore, inactivation of the carbohydrate binding site of Con A by demetallization greatly reduces the extent of thyroid peroxidase binding. Reactivation of the carbohydrate binding site by the addition of Ca2+ and Mn2+ to demetallized Con A-agarose restores thyroid peroxidase binding. These and other experiments suggest that htyroid peroxidase is, like several other peroxidases, a glycoprotein. In addition, the interaction between thyroid peroxidase and Con A-agarose may provide a new purification tool for thyroid peroxidase.