ə¦denəsə̇l-, ˌad ə n¦ōs-, -ˌsilˌ noun
Etymology: adenos ine + -yl + methionine
: the active sulfonium form of methionine C 15 H 22 N 6 O 5 S that acts as a methyl group donor in various biochemical transmethylation reactions (as the formation of epinephrine or creatine), that is formed when methionine reacts with ATP, and that is an intermediate in the formation of homocysteine; S -adenosylmethionine