An Improved Assay Method for Thyroid Peroxidase Applicable for a Few Milligrams of Abnormal Human Thyroid Tissues
A peroxidase assay method (Mini assay method) which is applicable for a minute amount (as small as a few mg) of thyroid tissue was developed, employing guaiacol or iodide as the second substrate. This method is a modification of the previous one (Ordinary assay method): the volume of the reaction mi...
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Published in | Journal of biochemistry (Tokyo) Vol. 98; no. 3; pp. 637 - 647 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Oxford
Oxford University Press
01.01.1985
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Subjects | |
Online Access | Get full text |
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Summary: | A peroxidase assay method (Mini assay method) which is applicable for a minute amount (as small as a few mg) of thyroid tissue was developed, employing guaiacol or iodide as the second substrate. This method is a modification of the previous one (Ordinary assay method): the volume of the reaction mixture was reduced to about one-tenth with prior solubilization of the enzyme. The correlation between the Mini assay and Ordinary assay methods, and between the guaiacol and iodide assays by both methods were satisfactorily good, but the iodine content of thyroglobulin was found to be not directly correlated to the peroxidase activities. Protein-based specific activities of peroxidase from normal human thyroid tissue were about 0.030 guaiacol units/mg protein and 0.0066 iodide units/mg protein, which were slightly higher than those of porcine thyroid tissue. The Mini assay method developed in the present study was used for the determination of peroxidase activity in a small amount (1–8 mg) of thyroid tissue obtained by means of a needle biopsy from patients with thyroid disorders. One specimen (goitrous cretinism) showed no peroxidase activity in both the guaiacol and iodide assays, and three specimens (two chronic thyroiditis, one familial nontoxic goiter) possessed no ability to catalyze the oxidation of iodide in spite of the high reactivity towards guaiacol, suggesting the presence of an abnormal peroxidase in these tissues. |
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Bibliography: | ark:/67375/HXZ-S80T2973-1 istex:1D64F30660EFE9D644E44B9AFDDBC04939255933 ArticleID:98.3.637 1 This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan (No. 58580096). Preliminary reports of portions of this work were presented at the 55th Annual Meeting of the Japanese Biochemical Society, October 1982, and at the 55th Annual Meeting of the Japan Endocrine Society, November 1983. ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0021-924X 1756-2651 |
DOI: | 10.1093/oxfordjournals.jbchem.a135320 |