Accession Number : AD0442066

Title :   ENZYMIC O-METHYLATION OF IODINATED PHENOLS AND THYROID HORMONES,

Corporate Author : WISCONSIN UNIV MADISON

Personal Author(s) : Tomita,Kenkichi ; Cha,Chung-Ja Mo ; Lardy,Henry A.

Report Date : 09 AUG 1963

Pagination or Media Count : 6

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)

Descriptors :   (*ENZYMES, BIOCHEMISTRY), (*BIOCHEMISTRY, ENZYMES), THYROID HORMONES, PHENOLS, CHROMATOGRAPHIC ANALYSIS, TISSUE EXTRACTS, LIVER, RATS, CHEMICAL REACTIONS

Distribution Statement : APPROVED FOR PUBLIC RELEASE