Studies on the biosynthesis of iodotyrosines: a soluble thyroidal iodide-peroxidase tyrosine-iodinase system.

摘要: A soluble enzyme functioning as an iodide-peroxidase and tyrosine-iodinase complex has been prepared from sheep thyroid tissue. The is detached cell particles by chymotrypsin digestion in the presence of deoxycholate, followed a butanol acetone extraction procedure. It can be purified diethyl-amino-ethyl cellulose column chromatography. During preparation specific activity enhanced fiftyfold. appears to basic protein which does not contain porphyrin group. no cytochrome oxidase activity. Iodinase thermolabile, dependent on H2O2 source. Under suitable conditions forms both diiodotyrosine monoiodotyrosine tyrosines, iodinates proteins. Tyrosine are its only well-defined amino acid substrates. Methimazole behaves assay system strict competitive inhibitor iodide.