The Effects of Polyhydric and Monohydric Alcohols on the Heat Induced Reversible Denaturation of Chymotrypsinogen A

Abstract

The reversible thermal denaturation of chymotrypsinogen A was investigated in aqueous solutions of mono‐, di‐ and polyvalent alcohols. Sorbitol and erythritol show a stabilizing effect, whereas the di‐ and monovalent alcohols are destabilizing. Divalent alcohols have a less destabilizing influence than monovalent alcohols when equimolecular proportions of ‐CH 2‐ and / or –CH 3 groups are present. Stabilizing effects of the polyalchols can be explained in terms of a lessened H bond rupturing capacity of the medium. The destabilizing by di‐ and movovalent alcohols is attributed to their hydrophobic interaction with the protein, which increases with the number of ‐CH 2‐ and, or ‐CH 3 groups and decreases with the number of ‐OH groups. Chymotrypsinogen A is more destabilized by hydrophobic alcohols than ribonuclease.