Savinase proteolysis of insulin Langmuir monolayers studied by surface pressure and surface potential measurements accompanied by atomic force microscopy (AFM) imaging

► The enzymatic action of Savinase on an insulin monolayer at the air-water interface was studied. ► We applied classical surface pressure and surface potential measurements and AFM imaging. ► We measured simultaneously changes of the surface area and the surface potential versus time. ► An appropriate kinetic model was applied, and the global kinetic constant was obtained. ► The AFM images revealed the state of the insulin monolayers before and after the Savinase action.