sentences:  This enzyme has been of particular interest because it is a classic example of how pKa values of ionizable groups in the enzyme active site can be significantly perturbed.Specifically, the pKa value of lysine 115 in the active site is unusually low, allowing for the formation of a Schiff base intermediate and catalysis.Acetoacetate decarboxylase is an enzyme with major historical implications, specifically in World War I and in establishing the state of Israel.