Dear colleagues, We have a target where people have measured Kd's for ligands using radioligand binding assays. Several publications report Kd's of single digit nanomolar and we are able to reproduce that data using this assay format. When we try to do the same measurement using ITC, we generate beautiful data, but the Kd's from ITC are at least 100-fold weaker. Does anyone have a suggestion how to reconcile this huge difference?
SPR studies show the ligands have a very long residence time, so one thing I wondered is if ITC can underestimate a Kd if the off-rate is on the order of minutes-hours. Is this a reasonable explanation? Please, any other ideas are welcome. Best, Nick -- [This e-mail message may contain privileged, confidential and/or proprietary information of H3 Biomedicine. If you believe that it has been sent to you in error, please contact the sender immediately and delete the message including any attachments, without copying, using, or distributing any of the information contained therein. This e-mail message should not be interpreted to include a digital or electronic signature that can be used to authenticate an agreement, contract or other legal document, nor to reflect an intention to be bound to any legally-binding agreement or contract.]
