Fluorescence studies on the active sites of proteinases

Summary Recent studies on the interaction of several proteinases (pepsin, papain, chymotrypsin, trypsin, thermolysin) with specific substrates or inhibitors bearing a fluorescent probe group have shown that the extended active sites of these enzymes differ in their conformational flexibility. In addition the use of such extrinsic probe groups, measurements of changes in the intrinsic tryptophan fluorescence, and of the energy transfer from tryptophan to a probe group, have given further information about the flexibility of the active sites of proteinases.