Most important amino acid which acts as methyl group donor-

Ans. is 'b' i.e., Methionineo Methionine is activated into S-adenosylmethionine, which then transfers its methyl group to an acceptor. Thus methionine acts as methyl donor in transmethylation reactions.o Some of the important transmethylation reactions are-i) Norepinephrine - Epinephrineii) Phosphatidylethanolamine - Phosphatidylcholineiii) Gunaidoacetate - Creatineiv) Ethanolamine - Cholinev) Acetyl serotonin - Serotoninvi) Nucleotides - methylated nucleotides