Scatchard plot by excel? - (Aug/15/2014 )

I already calculate the Schachard pot and have it as a dots that look like concave up plot but I want to draw the fitting line. Can we draw fitting curve for scatchard plot by excel? what is the equation for that?

thank you  

a scatchard plot should give you a straight line with a slope that equals (-)affinity constant.

look at these wikipedia pages: scatchard equation, scatchard plot.

be happy you can use excel, i had to do them by hand (before excel, or visicalc, for that matter, existed).

Thank you mdfenko, but I have a dimer that has different affinity to the ligand. I should be seeing concave up or concave down representing the cooprerativity for this enzyme. 

Excel can do this for you, but it isn't good at fitting lines (at least it wasn't last time I tried), you would be better off using a proper graphing tool such as GraphPad Prism, which will not only fit the curve for you, but also give you residual plots and the like so you can determine if you have the correct fit.

we were using a protein that showed a cooperative effect, as well. what we found was multiple linearity, with breaks at transition points.

Thank you but can I give excel fitting equation? there is equation somewhere that I can use.

No, there isn't an equation for the line until you fit one, which is done through statistical analysis of the data. Typically for first order curves you need to use least squares distance analysis.