The present invention provides compounds that function as hydrolytic enzyme inhibitors (inactivators) and substrates. These compounds are useful in assays to detect and measure levels of hydrolytic enzyme activity and are more particularly useful in treatment regimens for various disease states and conditions implicating the underlying specific hydrolytic enzyme. Examples of hydrolytic enzymes include, but are not limited to, phospholipases, lipases, esterases, proteases, etc.