title: A technical improvement for the thyroid peroxidase iodination assay.
abstract: Thyroid peroxidase (TPO) iodination activity is generally evaluated in vitro by the iodination of poorly iodinated thyroglobulin or bovine serum albumin, followed by separation of protein-bound and inorganic iodide by paper chromatography. Precipitation of protein-bound iodine by trichloroacetic acid (TCA) was evaluated as an alternative to the time-consuming paper chromatographic separation (PC) in normal rat TPO preparations. The protein-bound iodine estimates as well as the iodination activities determined by these two procedures were significantly correlated (r = 0.95 and 0.98, respectively, P less than 0.001), and the iodination activities regression line slope (b = 0.97 +/- 0.11) was not different from 1. The protein-bound iodine separation by TCA is simpler and faster, without loss of precision. Thus, it can be a useful alternative step in the thyroid peroxidase iodination assay.
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brasil.
authors.forename: D P
authors.initials: DP
authors.lastname: Carvalho-Guimarães
authors.forename: C F
authors.initials: CF
authors.lastname: Ramos
authors.forename: D
authors.initials: D
authors.lastname: Rosenthal
mesh_terms: D000818:Animals; D002854:Chromatography, Paper; D066298:In Vitro Techniques; D007453:Iodide Peroxidase / Q000378:metabolism*; D007455:Iodine / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats; D011919:Rats, Inbred Strains; D012044:Regression Analysis; D013961:Thyroid Gland / Q000502:physiology*; D014238:Trichloroacetic Acid / Q000494:pharmacology
chemical_list: D014238:Trichloroacetic Acid; D007455:Iodine; D007453:Iodide Peroxidase