Adenosylhomocysteinase (AHCY) (EC 3.3.1.1) or S-adenosylhomocysteine hydrolase (SAHH); is an enzyme that catalyzes the reversible hydrolysis of S-Adenosyl Homocysteine (SAH) to adenosine and homocysteine. AHCY regulates the intracellular SAH concentration which in turn regulates S-adenosyl methionine (SAM)-dependent methyltransferases. Down-regulation of AHCY has been associated with certain forms of cancer and Huntington's disease, while in Wilson's disease; the enzyme is inhibited by the accumulated copper. Mutations in the AHCY gene cause SAHH deficiency disease. AHCY Activity Assay kit can kinetically measure AHCY activity by detecting adenosine generation resulting from the hydrolysis of SAH. Adenosine is detected via a multi-step reaction, resulting in the generation of an intermediate that reacts with the OxiRed; Probe. The fluorescent product is measured at Ex/Em = 535/587 nm. Limit of quantification (L.O.Q) is 1 μU recombinant human AHCY.