In enzymology, a ricinine nitrilase (EC 3.5.5.2) is an enzyme that catalyzes the chemical reaction

ricinine + 2 H₂O 3-carboxy-4-methoxy-N-methyl-2-pyridone + NH₃

Thus, the two substrates of this enzyme are ricinine and H₂O, whereas its two products are 3-carboxy-4-methoxy-N-methyl-2-pyridone and NH₃.

This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in nitriles. The systematic name of this enzyme class is ricinine aminohydrolase. This enzyme participates in nitrogen metabolism.

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