In enzymology, a staphylopine synthase () is an enzyme that catalyzes NADPH-dependent reductive condensation of pyruvate to the intermediate (2S)-2-amino-4-{[(1R)-1-carboxy-2-(1H-imidazol-4-yl)ethyl]amino}butanoate, which is the last step in the biosynthesis of the metallophore staphylopine.