calculating IC50 - help needed (Nov/23/2009 )

Hi..can anyone tell me how can i calculate IC50..i am using some inhibitors for the enzymes...and where can i get information about how to calculate IC50..

Make a Dose-Response curve that goes from 0% to 100% inhibition.
Plot concentrations on a logarithmic scale - you should get a nice sigmoidal curve.
Pick your 50% inhibition point and find the corresponding concentration, this is your IC50 (or the log thereof, if you plotted concentrations on a log scale).

Oh okie...thanks a lot.this was realy helpful..i was stuck up with this from one week...thank you..