N-methyltyramine: Formation in Opuntia clavata and metabolism in Coryphantha macromeris var. Runyonii

-Administration of tyramine-[1-¹⁴C] to Opuntia clavata resulted in the formation of labeled N-methyltyramine. This procedure established the biosynthetic origin of the major alkaloid in this cactus as well as providing a radiolabeled chemical that was not commercially available. The N-methyltyramine-[1-¹⁴C] was in turn administered to Coryphantha macromeris var. runyonii to determine its metabolic role in the biosynthesis of the psychoactive cactus alkaloid normacromerine (N-methyl-3,4-dimethoxy-β-hydroxyphenethylamine). This feeding experiment established N-methyltyramine as a precursor to normacromerine.