Effect of X-Rays, Ultraviolet Light, and Chemicals on the Kinetic Parameters of Chymotrypsin

The effects of various agents on the kinetic parameters K/sub m/ (Michaelis constant) and V (maximum velocity) of chymotrypsin were studied. X irradiation increases K/sub m/ and decreases V. In solution, chymotrypsin is more sensitive when irradiated in the absence of oxygen; in the dry state, the enzyme is more sensitive when irradiated in the presence of oxygen. The effect of uv light on chymotrypsin in solution appears to depend on the wavelength of the incident light. The effect of urea or heat is to decrease V without change in K/ sub m/, whereas peracetic acid increases K/sub m/ without change in V. The implications of the observed changes in the kinetic parameters of chymotrypsin in relation to the structure of the enzyme are discussed. (auth)