Enzyme Adsorption Kinetics at Air/Fluid Interfaces

An understanding of enzyme adsorption kinetics and enzyme activity at air/fluid and fluid/fluid interfaces is essential for utilization of enzymes as biocatalysts in complex fluids. The enzyme Hyaluronidase was investigated and the adsorption isotherms were determined via surface tension analysis. A pendant drop tensiometer was used to measure the equilibrium surface tension of Hyaluronidase at the air-water interface. Digital images of the drop were recorded over time and fit to the Young-Laplace equation to determine the surface tension. It is demonstrated that the adsorption of Hyaluronidase at the liquid interface is therefore reversible in a thermodynamic sense. The focus of the present work is the measurement of the enzyme activity at the air-water interface. These experiments are untaken by convective exchange of the bulk phase of the drop with an aqueous solution of the biomacromolecule Hyluronic acid (HA), the substrate on which the enzyme acts and measuring the change in the molecular weight distribution of HA with time.