The effect of substrate size upon hyaluronidase action

Abstract

1. 1. Evidence has been presented indicating that the reactive unit of hyaluronate is a hexasaccharide. 2. 2. This fact has been used to explain the changes in the free energy and entropy of complex formation with changing substrate chain length. A similar argument has been presented to explain the constant value for the thermodynamics of activation and the enthalpy of complex formation with changing substrate size. 3. 3. The decrease in the activity of hyaluronidase with substrate molecular weight is related to the free energy of complex formation. The chain length of the substrate when the change in the free energy of formation is zero agreed closely with the observed substrate size in equilibrium mixtures. 4. 4. The relationship between the free energy of complex formation and chain length has been used to show that the Km of hyaluronidase closely approximates an equilibrium constant, and hence the validity of the previous work is indicated.