S adenosylhomocysteine deaminase

In enzymology, a S-adenosylhomocysteine deaminase (EC 3.5.4.28) is an enzyme that catalyzes the chemical reaction

S-adenosyl-L-homocysteine + H₂O ⇌ S-inosyl-L-homocysteine + NH₃

Thus, the two substrates of this enzyme are S-adenosyl-L-homocysteine and H₂O, whereas its two products are S-inosyl-L-homocysteine and NH₃.

This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in cyclic amidines. The systematic name of this enzyme class is S-adenosyl-L-homocysteine aminohydrolase. This enzyme is also called adenosylhomocysteine deaminase.