Bke2 Biochemistry Exercises

Group exercise: Mechanisms of enzyme regulation

Why is regulation important in biological systems. Discuss!
Name as many different modes of regulation you can think of. Which type of modification of the protein is required in each case? Is the modification reversible or irreversible?
Discuss and try to explain allostery. Allostery can be homotropic or heterotropic. Explain. What does positive cooperativity mean? Which glycolytic enzymes are allosterically regulated, and how?
If you separated hemoglobin into dimers of (a+b) subunits, would you expect the dimers to bind more or less O₂ at low O₂ tensions? Explain. What effect would 2,3-bisphosphoglycerate have on oxygen binding?
What does the curve for the dependence of the reaction velocity on the substrate concentration for an allostrically controlled enzyme look like? Do these enzymes follow Michaelis-Menten kinetics?
Explain the term feedback control. Why is it necessary?
Discuss the details of proteolytic activation. What may be the reasons for using protelytic cleavage as the means to control e.g. blood clotting and digestive enzymes?

Reading material: Horton chapters 4.13 5.10 6.8 9.12 10.2 11.5 12.6 13.3 13.7 17.20 18.2 18.7

Lectures:
Mechanisms of enzyme regulation

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