Sepiapterin deaminase

In enzymology, a sepiapterin deaminase (EC 3.5.4.24) is an enzyme that catalyzes the chemical reaction

Thus, the two substrates of this enzyme are sepiapterin and H₂O, whereas its two products are xanthopterin-B2 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 sepiapterin aminohydrolase.