体外甲状腺球蛋白碘化过程中过氧化氢和碘化物对过氧化物酶和葡萄糖氧化酶的失活作用。

Inactivation of peroxidase and glucose oxidase by H2O2 and iodide during in vitro thyroglobulin iodination.

作者信息

Wildberger E, Kohler H, Jenzer H, Kämpf J, Studer H

出版信息

Mol Cell Endocrinol. 1986 Jul;46(2):149-54. doi: 10.1016/0303-7207(86)90093-6.

Abstract

Thyroglobulin iodination and thyroxine synthesis in vitro require the presence of peroxidase, H2O2 and iodide. H2O2 is usually continuously generated by glucose oxidase (GO) and glucose. The aim of this study was to investigate whether the two enzymes could possibly be inactivated by a particular concentration of H2O2 or iodide present during incubation. The results revealed that both enzymes were indeed inactivated under two distinct conditions: Lactoperoxidase and thyroid peroxidase were inactivated by modest concentrations of H2O2 accumulating during incubation. Glucose oxidase was inactivated by an oxidized species of iodine or singlet oxygen produced in the catalytic cycle. The results may explain some hitherto unsolved discrepancies between different iodination procedures. Moreover they may have an impact on the regulation of in vivo thyroglobulin iodination and hormone synthesis.

摘要

甲状腺球蛋白的碘化作用及甲状腺素的体外合成需要过氧化物酶、过氧化氢（H₂O₂）和碘化物的存在。H₂O₂通常由葡萄糖氧化酶（GO）和葡萄糖持续生成。本研究的目的是探究这两种酶是否可能在孵育过程中被特定浓度的H₂O₂或碘化物灭活。结果显示，这两种酶确实在两种不同条件下被灭活：乳过氧化物酶和甲状腺过氧化物酶在孵育过程中积累的适量H₂O₂作用下被灭活。葡萄糖氧化酶在催化循环中产生的碘的氧化物种或单线态氧作用下被灭活。这些结果可能解释了不同碘化程序之间一些迄今尚未解决的差异。此外，它们可能对体内甲状腺球蛋白碘化作用及激素合成的调节产生影响。