S-Adenosyl-L-homocysteineisanaminoacidderivativeusedinseveralmetabolicpathwaysinmostorganisms.S-Adenosyl-L-homocysteine(SAH)isanaminoacidderivativeandanintermediate,by-product,ormodulatorofseveralmetabolicpathways,includingtheactivatedmethylcycleandcysteinebiosynthesis.SAHisformedbythedemethylationofS-adenosyl-L-methionine.ItisalsoaproductofS-adenosyl-methionine(SAM)-dependentmethylationof
BIOLOGicalmolecules,includingDNA,RNA,andhistonesandotherproteins.Inhibitorsthatblockitshydrolysisarebeingdevelopedasanti-viral,anti-parasitic,anti-arthriticandimmunosuppressiveagents.