Biosynthetic relationship between sulfonium and N-methylated compounds in the red alga Vidalia volubilis

Tracer experiments have been carried out on Vidalia volubilis, whose hydrophilic fraction contains (S)-4-dimethylsulfonio-2-methoxybutanoate [1], (S)-N-methylaspartic acid [2], and 2-amino-5-trimethylammoniopentanoate [3], a betaine previously unreported in nature. The results have shown that 4-dimethylsulfonio-2-methoxybutanoate can act as methyl donor in the biosynthesis of N-methylaspartic acid but not in that of 2-amino-5-trimethylammoniopentanoate.