Binding curve analysis

[D.K.]

In article <rpg14-8080F6.11211609102001 at pegasus.csx.cam.ac.uk>, rpg at mrc-lmb.cam.ac.uk wrote:
>Hi,
>
>I have some binding isotherms (changes in fluorescence vs ligand 
>concentration) and desperately need to work out the Kds . . .  Single 
>binding site, Kd same order of magnitude as the protein conc. Using 
>Kaleidagraph it should be possible to plug the data into a macro to do 
>this, but I can't find one.  Anyone able to help?

Use any program that does least square non-linear regression. 
I use Sigma Plot for DOS. As ridiculous as Excel is for anything
scientific, it also does it. A bunch of programs have trial versions
that work for some time - and you only need couple runs. 
Microcal Origin and GraphPad Prism are such products (both 
very good), Sigma Plot from Windows is OK, but I am not sure
if demo is fully funtional these days. There are certainly others.

DK