Physical aspects of the inhibition of enzymes by hydrocarbons: the inhibition of alpha-chymotrypsin by chlorinated aromatics and alkanes.

The inhibition of alpha-chymotrypsin by a series of chlorinated hydrocarbons, including polychlorinated biphenyls, has been studied. The solubility of the hydrocarbons was determined by autocorrelation analysis of light scattering. Kinetic analysis indicated that inhibition of the enzyme occurs when 1-2 molecules of inhibitor bind per molecule of enzyme. Chlorinated aromatics including polychlorinated biphenyls were more potent than monochloroalkanes in inhibition of the enzyme. Considerable inhibition was seen when some compounds were present as micelles. Molar volume correlations suggest that chlorinated hydrocarbons exert effects on soluble enzymes similar to their effects on membrane-bound enzymes, and that a membrane lipid phase is not essential for this type of inhibition.