Here we will compare outcomes of the four alternative models for conditions when binding is weak and the off-rate is fast. The isomerization is chosen to be slow here. I choose binding affinity of 106 M-1 and the off-rate constant of 500 s-1. R and RL are separated by 100 s-1 and R* or R*L - by 100 s-1 from corresponding species. Isomerization equilibrium is shifted 5:1 toward *-forms. The reverse isomerization rate is 1 s-1 to make kex = 6 s-1 .
Location: Af_Bs/
 |
 |
 |
 |
Simulate setup U_RL_Af_Bs |
|||
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
| Both forward and reverse titrations look the same 2-site binding | Very remarkable difference between the forward and reverse titration is expected in this case, easily detectable in spectra. | Both forward and reverse titrations will have the same signature of shifting disappearing peaks and the peaks appearing at fixed position, corresponding to more populated R*L. IMPORTANT: This spectral appearance is very similar to U_R2 model! Reverse and direct titration in that case will be different ! |
|
Back to Analysis of Direct and Reverse Titrations