Overvoltage and Solid State Kinetics of Reactions at Biological Interfaces.
NAVAL AIR DEVELOPMENT CENTER WARMINSTER PA CREW SYSTEMS DEPT
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The observed kinetics of several redox reactions occurring at biological interfaces are easily derived from the concept that overvoltage phenomena are rate-limiting, like at electrode surfaces. The observed kinetics of the enzyme cytochrome oxidase, which is a fragment of mitochondrial membrane, are predicted quantitatively and in detail from rate-limitation by diffusion plus ohmic overvoltages. The activation energy of the cytochrome oxidase reaction is observed to approximate the semiconduction activation energy of the dry enzyme as predicted by this theory. From rate-limitation by activation overvoltage, one easily predicts redox kinetics conforming to the Roginsky-Zeldovich or Elovich equation, as observed experimentally for free radical decay in eye melanin and photosynthetic granules and for decay of photoconductivity in nerve. Na and K transport across cell surfaces also show evidence of rate-limitation by activation overvoltage, suggesting that the cell surface should be regarded as a liquid-solid interface like an electrode. This view is supported by strong experimental evidence for structuring of cell water and for complexing of cell Na and K. Author
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