Physical Chemistry

Question

Hello,

Do you know what textbook I can find the formulas for the affect a competitor in solution has on the dissociation constant of two molecules with each other?

How would I find the relationship between the on rates, off rates, and Gibb's free energy?

Thank you so much!

Answer 1

So Joseph R.,

Competitive inhibitor means that it competes with the desired substrate for position on the active site. So if the competitor is on the active site, the desired substrate can't latch on. Therefore, the competitor reduces the number of molecules with active sites open in solution, and it is mathematically modeled as such. The molecules with active sites open, however, can bind the substrate just fine, so the on and off rate CONSTANTS are unaffected -- but the RATES on and off scale with the amount of molecules with active sites open! (Rate = rate constant * (reactants amounts expression)). And, the Gibbs Free Energy (I think the final apostrophe on Gibbs' is usually dropped?) is also unaffected (which governs the temperature dependence of the activation energty, the reaction is assumed to be slow with respect to binding and unbinding though these might also have some temperature dependence).

-- Cheers, --Mr. d.