Utilization of Betaine as a Methyl Group Donor in Tobacco.

Abstract
Methyl groups of betaine may be incorporated into the N-methyl group of nicotine in tobacco plant metabolism. Extent of incorporation was about the same as with methyl groups of methionine and choline. When choline-methyl-C14 was fed to tobacco plants, radio-active betaine and dimethylglycine appeared. This indicated that a choline oxidase was present and that some choline was oxidized to betaine before methylation of nicotine occurred.