The kinetic patterns and parameters of 12 alcoholic organic solvents of different classes inhibiting thermolysin-catalyzed synthesis of N-(benzyloxycarbonyl)-L-phenylalanyl-L-phenylalanine methyl ester (Z-Phe-Phe-OMe) in aqueous organic one-phase reaction system have been determined. All alcohols showed a linear mixed type inhibition. A kinetic model of inhibition is suggested. It was presumed that alcohols interact with substrate in the active site of thermolysin.