Use of an iodide-specific electrode to study lactoperoxidase-catalyzed iodination of l-tyrosine
✍ Scribed by Rose M. Threatte; Melvin J. Fregly; F. Peter Field; Patricia K. Jones
- Book ID
- 102915065
- Publisher
- John Wiley and Sons
- Year
- 1979
- Tongue
- English
- Weight
- 582 KB
- Volume
- 68
- Category
- Article
- ISSN
- 0022-3549
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✦ Synopsis
An in vitro method employing an iodide-specific electrode for monitoring lactoperoxidase-catalyzed iodination is described. The method utilized lactoperoxidase, potassium iodide, and a glucose--glucose oxidase system for the generation of hydrogen peroxide and l-tyrosine. As iodination of l-tyrosine proceeded, the free iodide concentration in solution decreased and was monitored by an iodide-specific electrode. The iodide electrode was reliable when compared to a 131I-method for measuring free iodide changes in solution. Increasing concentrations of resorcinol, a well-known inhibitor of thyroid peroxidase-catalyzed iodination, in the reaction mixture resulted in graded inhibition of the initial rate of lactoperoxidase-catalyzed l-tyrosine iodination. This in vitro system can be used to assess inhibitory activity of various antithyroid substances.