Accession Number:

AD0442066

Title:

ENZYMIC O-METHYLATION OF IODINATED PHENOLS AND THYROID HORMONES,

Descriptive Note:

Corporate Author:

WISCONSIN UNIV MADISON

Report Date:

1963-08-09

Pagination or Media Count:

6.0

Abstract:

An enzymic methylation of iodophenols has been described. The enzyme occurs in the soluble fraction of rat liver from which it has been partially purified. The enzyme utilizes S-adenosylmethionine as methyl donor. In contrast to catechol O-methyltransferase, iodophenol Omethyltransferase requires no divalent cation for activity. Among the substrates tested, 3,5diiodo-4-hydroxybenzoic acid was most rapidly methylated. Tetraiodothyroacetic acid was methlated at an appreciable rate, but triiodothyroacetic acid, thyroxine, and triiodothyronine were not significantly methylated under the conditions tried. Iodophenol O-methyltransferase was distinguished from catechol O-methyltransferase by its greater stability to heat and its lack of a requirement for divalent cations. The two enzymes were also differentiated by separations on calcium phosphate gel and on a diethylaminoethyl cellulose column and by varying distributions among the tissues of different animals. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE