As seen in figure 1, the 1H NMR spectrum of the hydrolysis reaction shows the depletion N-acetyl-DL-methionine (4.25 ppm, red dot) and the simultaneous appearance of the product, L-methionine (3.85 ppm, blue dot). Since the porcine acylase selectively hydrolyzes N-acetyl-L-methionine, the signal at 4.25 ppm never completely disappears because the D-enantiomer of the racemic mixture remains in the solution. From the integration data, the plot of N-acetyl-L-methionine concentration over time (figure 2) can be generated.