• Support PF! Buy your school textbooks, materials and every day products Here!

Allosteric enzmes

  • Thread starter aa2
  • Start date
  • #1
I have a exam question as a essay topic from past papers.I am confused about what it wants me to talk about.I need help regarding what the question is asking .

Discuss the mechanisms that can account for the allosteric properties of proteins and explain, using examples, the advantages of these properties to the organism.

Does it want me to talk about:
effectors , modulators
Rf orm and T from
MM kinetics and sigmoid curves

Please Please help.The answer they want is probably is simple but I don't understand what exactly it wants

Answers and Replies

  • #2
Science Advisor
Insights Author
Gold Member
2019 Award
Here's the approach I would take to writing this essay. First, I would briefly define the concept of allostery (here you would talk about allosteric effectors/modulators and how they differ from other effectors such as competitive inhibitors). In introducing allostery, it might be a good idea to give an example of a protein that exhibits allostery.

Next, I would discuss the mechanism of allostery. How does binding of ligand at one site of the allosteric protein affect binding of another ligand at a distant site? Here you would discuss the R and T forms of the enzyme. Also, be sure to mention the two classical models for allostery, the MWC and KNF models.

Finally, in explaining why allostery is advantageous, you would discuss how allostery affects the shape of the Michaelis-Menten curve and why changing the shape of the curve is helpful for the example enzyme you've chosen.
  • #3
Homework Helper
Gold Member
It asks for mechanisms. It probably wants you to do the mechanisms of Monod-Wyman-Changeux (MWC) and of Koshland et al.. It would want you to give examples of attempts at experimental verification. It would be good, in fact essential, to give examples of experimentally determined (by crystallography etc.) effects of effectors on conformation. You would probably be looking at hemoglobin, aspartate transcarbamylase, phosphorylase. Have you been given, or is there in your books, absolutely no clue about where to follow up on some of the above?
Last edited:

Related Threads for: Allosteric enzmes