Diisopropylphosphofluroridate (DIPF) and sarin (a nerve gas in the same family as DIPF) are inhibitors whose mode of inhibition is based on the formation of: Hydrogen bonds with enzymes like acetylcholinesterase Covalent bonds with enzymes like trypsin, chymotrypsin and elastase Covalent bonds with enrymes like cyclooxygenase (COX) Covalent bonds with enzymes like acetylcholinesterase