X- and γ-irradiation of Dilute Solutions of Chymotrypsin: The Active Intermediate

Summary

X- and γ-irradiation of dilute aqueous solutions of chymotrypsin in 10⁻³ M HCl or in water produce difference spectra, over the range 210–330 mµ, qualitatively similar to that obtained on reaction of the enzyme with hydroxyl radicals from Fenton's reagent.

The protection of the esterolytic properties of chymotrypsin against irradiation has been measured using BTEE as the substrate and sodium formate, acetone, glucose, ethanol and iso-propanol as protectors. The results obtained, when combined with absolute rate constants available for reactions of the hydroxyl radical, show that radical to be the predominant reactive species in the irradiation of dilute aqueous solutions of the enzyme.