Enzyme Kinetics

Problems for Classroom Discussion

Gale Rhodes
Department of Chemistry
University of Southern Maine
Portland, Maine 04104-9300

Revised 2006/07/14

Enyzme Kinetics and Inhibition: Example for Analysis in Class

(Data taken from Lindquist, R.N., Problems and Solutions Guide to Accompany Rawn's Biochemistry, Neil Patterson Publishers, 1990.)

The table gives enzyme-catalyzed reaction rates (initial rate, V0) measured at various substrate concentrations in solutions with [E] = 1.2 x 10-4 mmol/L.

  1. Use the data from Experiment 1 to calculate Vmax (in mmol/L-min), Km (in mmol/L), and kcat (in sec-1) for this enzyme-catalyzed reaction.
  2. Use the data from Experiment 2 to determine the apparent Vmax (in mmol/L-min), and Km (in mmol/L) in the presence of the inhibitor. From this information, determine the type of inhibition (competitive, noncompetitive or uncompetitive) and calculate the dissociation constant KI for the inhibitor. For help, see Summary of Kinetic Effects of Reversible Inhibitors.

Answers

An answer link will appear on the calendar after we discuss the problems in class.

Handing In Solutions To These Problems

If you are offered the opportunity to hand in solutions to these problems for grading, your solution for each question should include

  1. a printed graph from Excel (or other graphing program), with equation and correlation coefficient of line fitted to data;
  2. complete calculations, with units of all quantities, resulting in the answers expressed in proper units, and with proper significant digits.

Goodies

Biochemistry Resources