NCIt definition : An amino acid derivative and an intermediate in the synthesis of cysteine and adenosine.
S-adenosylhomocysteine (SAH) is formed upon S-adenosylmethionine (SAM)-dependent methylation
(homocysteine methionine cycle) of biological molecules, such as DNA, RNA, and proteins.
It is then hydrolyzed by S-adenosylhomocysteine hydrolase to form adenosine and homocysteine.
As SAH modulates methylation dependent reactions, SAH levels and the ratio of SAH:SAM
may be used to assess methylation status of macrocolecules.;