Renin belongs to a class of enzymes called aspartyl proteases in which aspartate plays a catalytic role similar to serine in chymotrypsin. Renin inhibitors could potentially be used to treat high blood pressure. Two aspartate residues in the renin active site, Asp 32 and Asp 215, constitute a catalytic dyad, rather than the catalytic triad found in chymotrypsin. Select the correct reaction mechanism for peptide hydrolysis catalyzed by renin.