Protease inhibitors greatly facilitate the detection and determination of proteases, the study of their interactions with their substrates or effectors, and the investigation of the physiological roles of enzymes.
Synthetic low molecular weight inhibitors are particularly useful and are used for the purification of proteins, for the characterization of proteases and also for the suppression of unwanted catalytic activity.
Binding an inhibitor may prevent a substrate from binding to the active site of the enzyme and/or the enzyme from catalyzing its reaction. This inhibition can be reversible or irreversible. Irreversible inhibitors usually react with the enzyme and modify it chemically. They bind covalently and modify key amino acid residues necessary for enzymatic activity.
Conversely, reversible inhibitors bind in a non-ccovalent manner and different types of inhibitions result depending on whether these inhibitors bind the enzyme, enzyme-substrate complex (ES) or both.