S-adenosyl-L-homocysteine
Encyclopedia
S-Adenosyl-L-homocysteine (SAH) is an amino acid
derivative used in several metabolic pathways in most organisms. It is an intermediate in the synthesis of cysteine
and adenosine.
SAH is formed by the demethylation
of S-adenosyl-L-methionine (SAM).
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
derivative used in several metabolic pathways in most organisms. It is an intermediate in the synthesis of cysteine
Cysteine
Cysteine is an α-amino acid with the chemical formula HO2CCHCH2SH. It is a non-essential amino acid, which means that it is biosynthesized in humans. Its codons are UGU and UGC. The side chain on cysteine is thiol, which is polar and thus cysteine is usually classified as a hydrophilic amino acid...
and adenosine.
SAH is formed by the demethylation
Demethylation
Demethylation is the chemical process resulting in the removal a of methyl group from a molecule.A common way of demethylation is the replacement of a methyl group by a hydrogen atom, resulting in a net loss of one carbon and two hydrogen atoms....
of S-adenosyl-L-methionine (SAM).