Trypsin Inhibition by Phenylmethylsulphonylfluoride with Reduced Wool as Substrate

Abstract

WE are trying to dissolve native proteins from wool by the method of limited proteolysis^1,2. Unreduced wool is not attacked by trypsin and so, in our experiments, wool has been reduced under the mildest possible conditions which will allow trypsin digestion. We believe that these conditions do not cause denaturation of the wool³. Apparently, large protein fragments are dissolved from the reduced wool by trypsin, and in a synthetic boundary run⁴ in the Spinco model E ultracentrifuge, the unfractionated solution gave a schlieren peak, sedimentation coefficient of 3.1. One obstacle to further characterization of the dissolved proteins is the enzyme in the solution, which may continue to digest the fragments it has released from the fibre. This communication describes experiments which show that the inhibitor phenylmethylsulphonylfluoride (PMSF)⁵ will arrest the reaction of trypsin with reduced wool.