Immobilized Enzyme Reactors Enzymes are proteins that catalyze or enhance the rate of a chemical reaction. Enzymes are very specific in terms of the substrate (reactant) that they act on.

Enzymes are usually named after the substrate whose reaction is catalyzed. For example urease acts upon urea, heparinase acts on heparin. For example collagenase: E.C. 3.4.24.3

Allosteric interaction

Initial rate of reaction about equal to 2 mg/ml/min Out of substrate 1 unit = liberates 1 mol of glucose per minute from starch at pH = 4.8 and 60 oC

So we need to know: Enzyme reaction kinetics The effect of substrate diffusion on the observed reaction rate A design equation for the particular reactor of interest

Enzyme Kinetics

E + S <--> ES ---> E + P

Finding Vmax and Km from Experimental Data

Example 8.5 soluble heparinase kinetics

Km = 0.078 mg heparin/ml of solution Kcat = 0.891 mg heparin/U/hr 1 U = amount of enzyme needed to degrade 1 mg heparin/hr

Enzyme Activity Strongly Dependent on the pH

Enzyme Activity Depends on Temperature V = A exp(-E/RT)

Enzymes Also Denature if the Temperature is Too High Good Bad T increasing

Even Fluid Shear Forces Can Deactivate the Enzyme

Enzyme Immobilization

Ways to Immobilize An Enzyme