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SynopsisThe kinetics of denaturation of egg albumin have been determined for methanol, ethanol, propanol, and butanol. The reactions are first order in respect to protein but between 11th and 18th order for the alcohols. The denaturation reaction is characterized by a large temperature coefficient with little or no dependence on pH. There is a marked change of pH when proteins are denatured. A series of eight proteins has been studied. There is surprisingly little difference in susceptibility to alcohol denaturation between the various proteins. Methanol, ethanol, propanol, and butanol are strongly bound to egg albumin-butanol being the most strongly bound. The binding of alcohol is probably accompanied by protein dehydration. The polyhydric alcohols' behavior is much different. These alcohols do not denature proteins and the protein is hydrated. Sucrose produces the greatest degree of hydration.Singer' reviewed the properties of proteins in nonaqueous solvents and included a consideration of alcohols. Herskovitz et aL2 dealt with the optical properties of proteins dissolved in alcohols and described certain thermodynamic relations. Gerlsma3 has studied the effects of polyhydric and monohydric alcohols on the heat-induced reversible denaturation of chymotrypsinogen A.The present communication deals with three aspects of the interaction of alcohols with proteins. First, there is a simple description of the kinetics of denaturation of egg albumin (EA) by methanol (MeOH), by ethanol (EtOH), by propanol (PrOH), and by butanol (BuOH). We then report on the change of pH when a protein is denatured by alcohols; the pH-change method was successfully used in our study of the denaturation by guanid i~H C 1 .~ Lastly, we have looked at the binding of water and of polyhydric and of monohydric alcohols by proteins using equilibrium dialysis. We have previously reported on the binding of water and electrolytes to proteins employing equilibrium dialy~is.~ EXPERIMENTAL EA was prepared from fresh hen's eggs using Na2S04. The preparations were exhaustively dialyzed against distilled water and stored in the refrigerator under toluene. The concentration of the EA mother solution was determined by dry weight in a vacuum oven at 105OC for 24 hr.The MeOH, EtOH, PrOH, and BuOH were of reagent grade and, aside from appropriate dilution with water, used as obtained. The EtOH was from U S . Industrial Co.; the other alcohols were from Fisher Scientific Co.Before use, the alcohols were diluted with water to produce the following

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