S-Adenosylmethionine (SAM) Is Generated from the S N 2 Reaction of Methionine and ATP Methionine adenosyl transferase Driving force for the reaction is subsequent hydrolysis of triphosphate S N 2 reaction adenosine triphosphate (ATP) methionine S-adenosylmethionine (SAM)
S-Adenosylmethionine (SAM) Is A Biological Methylating Agent SAM-dependent methyl transferases O-, S-, and N-Methylation N-methylation: DNA and tRNA bases, amine side chains in proteins O-methylation: protein carboxylates, polysaccharide alcohols, neurotransmitter phenols S-methylation: Thiols S N 2 reaction
SAM at Work…
Methylation of Norepinephrine to Epinephrine by SAM and PNMT Phenylethanolamine- N-methyl transferase (PNMT) Adrenal cortex SAM norepinephrine Epinephrine (adrenalin)