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Pepsin inactivation by inert gases
NOTES FROM THE BIOCHEMICAL RESEARCH FOUNDATION ELLICE McDONALD, DIRECTOR
P e p s i n Inactivation by I n e r t Gases.--GEORGE M. NAIMARK* AND WILLIAM A. MOSHER. It is well known t h a t soluble globular proteins spread on quiescent gas-liquid interfaces to form two-dimensional monomolecular films of unfolded molecules. Since the bubbling of a gas through a liquid results in the rapid formation and collapse of gas-liquid interfaces, it is to be expected t h a t such t r e a t m e n t would result in the denaturation and subsequent inactivation of protein enzymes. It was found t h a t the bubbling of argon, nitrogen or an argon-butane mixture through solutions of low concentration (0.2 per cent) of U.S.P. Merck Pepsin resulted in the rapid inactivation of the enzyme. An atmosphere of inert gas was not sufficient to cause inactivation. T h e inactivation caused by gas bubbling was not reversed by prolonged standing and was not due to the introduction of impurities by the gas. We are led to conclude t h a t gas bubbling provides gas-liquid interfaces upon which the enzyme spreads and forms monomolecular films. T h e collapse of the bubbles crushes the films and mechanically alters the protein structure. This type of enzyme inactivation is therefore the result of surface denaturation followed by the destruction of the formed films and is an irreversible reaction. * Present address: Strong Cobb and Co., Inc., 2654Lisbon Road, Cleveland4, Ohio.
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P e p s i n Inactivation by I n e r t Gases.--GEORGE M. NAIMARK* AND WILLIAM A. MOSHER. It is well known t h a t soluble globular proteins spread on quiescent gas-liquid interfaces to form two-dimensional monomolecular films of unfolded molecules. Since the bubbling of a gas through a liquid results in the rapid formation and collapse of gas-liquid interfaces, it is to be expected t h a t such t r e a t m e n t would result in the denaturation and subsequent inactivation of protein enzymes. It was found t h a t the bubbling of argon, nitrogen or an argon-butane mixture through solutions of low concentration (0.2 per cent) of U.S.P. Merck Pepsin resulted in the rapid inactivation of the enzyme. An atmosphere of inert gas was not sufficient to cause inactivation. T h e inactivation caused by gas bubbling was not reversed by prolonged standing and was not due to the introduction of impurities by the gas. We are led to conclude t h a t gas bubbling provides gas-liquid interfaces upon which the enzyme spreads and forms monomolecular films. T h e collapse of the bubbles crushes the films and mechanically alters the protein structure. This type of enzyme inactivation is therefore the result of surface denaturation followed by the destruction of the formed films and is an irreversible reaction. * Present address: Strong Cobb and Co., Inc., 2654Lisbon Road, Cleveland4, Ohio.
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