Less point in dissiciation phase

Hello Everyone,
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.
Thanks
Monica

Hi Monica,

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.

Third option is to use another software package.
I can recommend Scrubber ( www.sprpages.nl/software-weblinks ). It is not free, but good value for money.

Kind regards

Arnoud

Hi Arnoud,
Thanks for the reply. Could you pls elaborate on seting sampling rates to high. I am Not sure I get it.
Thanks again
Monica

Hi Monica,

I know form the Biacore 2000 en T200 that it is possible to set the data sampling rate to high (10Hz) which means that you have more data points to analyse.

I am not sure that it is possible with a X100. I did not find anay reference to it.

Arnoud

Hi Arnoud,
I don't think it is available in BiacoreX100. Thanks for your help.
Regards
Monica