A Novel Parameter to Estimate the Minimum Number of Bound Ligands Needed to Activate an Ion Channel
✍ Scribed by Tiziana Castrignanò; Filippo Aluffi-Pentini; Valerio Parisi
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 136 KB
- Volume
- 199
- Category
- Article
- ISSN
- 0022-5193
No coin nor oath required. For personal study only.
✦ Synopsis
We consider the Hill coe$cient obtained from concentration}response curves and we stress the di!erences between the use of binding and the use of current for the response. We "rst show that in order to estimate the cooperativity of binding sites one must use the coe$cient obtained from the binding curves and not that obtained from the current curves. For what concerns the estimation of the minimum number of bound ligands needed to activate the channel, while the coe$cient obtained from the binding is simply not applicable, we show that the coe$cient obtained from the current is not appropriate. We "nally introduce a novel parameter that predicts the number of ligand molecules required to open the channel from current measurements at very low ligand concentration. The above considerations are exempli"ed by a few theoretical models.