text: <unk>  <unk>  is a coenzyme involved in methyl group transfers.<unk>  was first discovered in 1952. It is made from adenosine triphosphate (ATP) and<unk>  by<unk> <unk> transferase EC 2.5.1.6. Transmethylation, transsulfuration, and aminopropylation are the metabolic pathways that use<unk> . Although these anabolic reactions occur throughout the body, most<unk>  is produced and consumed in the liver.
  The methyl group (CH3) attached to the<unk>  sulfur atom in<unk>  is chemically reactive. This allows donation of this group to an acceptor substrate in transmethylation reactions. More than 40 metabolic reactions involve the transfer of a methyl group from<unk>  to various substrates such as nucleic acids, proteins, and lipids.
  In bacteria,<unk>  is bound by the<unk>  riboswitch, which regulates genes involved in<unk>  or cysteine biosynthesis.
option_0: S-Adenosyl methionine
option_1: Uridine triacetate
option_2: 5-Methyltetrahydrofolate
option_3: Nicotinamide adenine dinucleotide
option_4: Triethanolamine
option_5: Uridine diphosphate galactose
option_6: N-Acetylglutamic acid
option_7: 5,10-Methylenetetrahydrofolate