Question

Protein a binds to protein b to form a complex, ab: a + b  ab a cell contains an equilibrium mix of protein a at a concentration of 1 µm, protein b at a concentration of 1µm, and the complex ab also at 1 µm.
a. What is the equilibrium constant, keq, for the reaction a + b  ab?
b. What would the equilibrium constant be if a, b, and ab were each present in equilibrium at a concentration of 1 nm?
c. At this lower concentration, about how many extra hydrogen bonds would be needed to hold a and b together tightly enough to form the same proportion of the ab complex? Note: free energy change is related to the equilibrium constant by the equation ∆go = -2.3 rt log k, where r is 1.98 x 10-3 kcal/k mole) and t is 310 k.

Answer 1

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