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Published November 1948 | Published
Journal Article Open

Dimethylthetin and dimethyl-β-propriothetin in methionine synthesis


In a previous communication it was shown that choline and betaine are effective in promoting methionine synthesis from homocysteine in tissue homogenates (1). Data presented in this paper indicate that dimethylthetin, (CH3)2+SCH2COO-, which has been shown by Welch (2) to be lipotropic and has been reported by du Vigneaud (3) to promote growth on a methionine-free, homocysteine-containing diet, is 20 times as active as betaine in methionine formation. Dimethyl-β-propiothetin, (CH3)2+S(CH2)2COO-, recently isolated from Polysiphonia fastigiata by Challenger and Simpson (4) is also highly active. The enzyme for this transmethylation is found in the liver and kidney of all animals tested. Its high activity and general distribution suggest its biological importance in methionine synthesis.

Additional Information

Copyright © 1948 American Society of Biological Chemists. (Received for publication, May 5, 1948) Presented before the meeting of the American Society of Biological Chemists at Atlantic City, March 15-19, 1947. Aided by a grant from the United States Public Health Service.

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