title: Kinetic characterization of thyroid peroxidase enzyme and its inhibition by autoantibodies.
abstract: A guaiacol method was developed to measure thyroid peroxidase (TPO) activity and the inhibitory effect of anti-TPO antibodies using purified porcine TPO. The TPO preparation was characterized kinetically and identified by western-blotting technique. The K(M) for guaiacol determined in vitro was 5.6 x 10(-4) M. Investigating the effect of IgG's from 23 hypothyroid patients on TPO activity inhibition was detected in 15 cases with the guaiacol method. It was found that anti-TPO antibodies exerted a competitive inhibition TPO activity with respect to the substrate guaiacol. The inhibition is carried by IgGF(ab')2 fragment. We wanted to gain a method which is interpreted immunologically and can be well employed in the clinical practice.
authors.affiliation: Department of Pathology, Kenézy Teaching Hospital, Debrecen, Hungary.
authors.forename: V
authors.initials: V
authors.lastname: Kaczur
authors.forename: G
authors.initials: G
authors.lastname: Vereb
authors.forename: I
authors.initials: I
authors.lastname: Molnár
authors.forename: G
authors.initials: G
authors.lastname: Krajczár
authors.forename: C
authors.initials: C
authors.lastname: Balázs
mesh_terms: D000818:Animals; D001323:Autoantibodies / Q000276:immunology*; D006139:Guaiacol / Q000378:metabolism; D006801:Humans; D007453:Iodide Peroxidase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007700:Kinetics; D013552:Swine
chemical_list: D001323:Autoantibodies; D006139:Guaiacol; D007453:Iodide Peroxidase