Thanks a lot for the kind reply. I used CM5 chip at pH 7.4. I am not quite sure about the PI of my protein but I have different truncations of my protein which behaved similarly. I can fit my data quite good with the Chi2 around 1 and Rmax 150. The kon is about 10e4 and the KD is around 0.2 nM. The concentration of analytes I used was from 100 nM to 5 nM. I used a control buffer which can disrupt the binding. In that buffer, no binding was observed.
I also used fluorescence anisotropy to measure the Ki of the interaction which showed a 1 nM binding compared with the 0.2 nM binding in the SPR assay. On Wed, Feb 20, 2013 at 12:03 PM, xianchi dong <dongxian...@gmail.com>wrote: > Dear all, > > Recently I have measure a set of kinetic data of a receptor ligand > interaction using BIAcore 3000. To my surprise, the dissociation rate is > very low (~ 10e-6). During the measurement, I use a long dissociation time > (2 hours) .I repeat several time which give very similar results. So I am > wondering if the BIAcore can measure such a low off-rate kinetic. What is > the limitation of BIAcore? Any review about that? > > Thanks in advance. > > Xianchi Dong > Research Fellow > Children's Hospital Boston > Harvard Medical School >
