HINGE-BENDING DEFORMATION OF ENZYME OBSERVED BY MICROWAVE DIELECTRIC MEASUREMENT

A dielectric relaxation peak due to an intramolecular motion in the ac tive site of typsin was first observed in aqueous solution below the f reezing temperature of bulk water by a time domain reflectometry metho d. If trypsin inhibitor is added to the solution, it vanishes. It is s uggested that the motion observed is a hinge-bending deformation givin g rise to the enzymatic activity of trypsin, which is prohibited by li nkage of the trypsin inhibitor. Relaxation time of the motion is 3 x 1 0(2) ns at -10 degrees C. (C) 1996 John Wiley & Sons, Inc.