I assume you use CM5 chips ? I further assume you run at pH 7.5 perhaps ? What's the pI of your analyte ? > 7.5 ? Do you get significant binding to your reference cell under the conditions you are running ? You might get rebinding to your negatively charged surface and the dissociation you are measuring might not really be correct (masked through rebinding) Check that first I would say. You can measure low picomolar dissociations. I recently had one with ~80 pM.
Jürgen ...................... Jürgen Bosch Johns Hopkins University Bloomberg School of Public Health Department of Biochemistry & Molecular Biology Johns Hopkins Malaria Research Institute 615 North Wolfe Street, W8708 Baltimore, MD 21205 Office: +1-410-614-4742 Lab: +1-410-614-4894 Fax: +1-410-955-2926 http://lupo.jhsph.edu On Feb 20, 2013, at 12:03 PM, xianchi dong 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
