[A study of the Brownian movement of alpha-chymotrypsin molecules by the spin probe method]

The rotation of alpha-chymotripsin in water solution is studied by use of nitroxyl radical, which is adsorbed by the alpha-chymotrypsin. It has been shown that under the conditions used the probe is fixed on the rotating diffusive protein monomer. Theoretical calculations of possible rotation correlation times for alpha-chymotripsin molecule were performed taking into account hydration and non-spherical shape. Experimental data obtained are in good agreement with theoretical values.