Kinetics of protein denaturation at gas—liquid interfaces

Abstract Denaturation of acid phosphatase at the gas-liquid interface has been studied experimentally and analytically for protein solution in laminar flow with a free gas-liquid interface. The rate of loss of enzyme activity due to interfacial denaturation is shown to depend on gas-liquid contact time and surface generation rate. At the molecular level, both adsorption and denaturation are rate-limiting at short contact times. At long contact times adsorption and denaturation are complete, and the overall loss of enzyme activity depends only on the surface generation rate. Experimental results are consistent with a primary adsorbed layer of unfolded enzyme in an amino acid monolayer. The first-order rate constant for interfacial inactivation is estimated to be 0.26 sec−1 at 37°C. Interfacial denaturation is reduced in the presence of additional surface-active materials.

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