I have been studying binding kinetics with BiacoreX100. The problem is that the dissociation phase drops sharply in the curves and there are not enough points in dissociation point so the fitting is really bad. I have tried with increased dissociation time from 200 sec to 600 sec but in vain. Pls see the attached figure.
Details: Chip -NTA
Buffers: HEPES buffer with Surfectant.
Flow rate for Ni-10uL/min
Flow rate for ligand: 5uL/min
I really appreciate any help/suggestions.
Is it possible to set the sampling rate to high with the X100? Then you have more points to analyse. Longer dissociation will not help you since the information of the dissociation is in the first few seconds because it is so fast.
An alternative is to do equlibrium analysis since you have equilibrium in all curves. This will give you de KD but not the kinetics.