Fitting noncompetitive, uncompetitive and mixed enzyme inhibition models.

If you use Prism 6 or later, refer to the description of these equations in the Regression (curve fitting) guide that you can access from the program.

First review the difference between different kinds of inhibition in this handout from Dr. Jakubowski, and in the book by Copeland (citation below). 

Prism 5
Prism 5 comes with a set of build in equations, including those for competitive, noncompetitive, uncompetitive and mixed enzyme inhibition . Follow those links to the Prism 5 help system for explanations of the four inhibition models, and how to fit these models with Prism 5. Those pages reference equations in an earlier book by Copeland, and the equation numbers are not correct. Here are the correct equation numbers referring to Copeland's book on enzyme inhibition referenced below.

• Competitive inhibition: Equation 3.1
• Noncompetitive inhibition: Equation 3.4
• Uncompetitive inhibition: Equation 3.6
• Mixed model inhibition: Equation 3.2

Prism 4
Read the links above to learn the difference between the various forms of enzyme inhibition.

This step-by-step example for Prism 4 shows how to use global fitting to fit a family of enzyme kinetics curves to a competitive enzyme model:
   Computing K_i for a Competitive Enzyme Inhibitor

This Prism file fits one set of data to all four models. The noncompetitive model fits the data fairly well, as does the mixed model. But the other two models do not. Thanks to Eric M. Shepard and David M. Dooley of Montana State University for providing the file (to which they own the copyright), and to Henry LIu of Galileo who provided the equation for the mixed model.