[pinke]

is there any expert in enzyme inhibitory studies, please reply ...

i have absorbance values of 3 inhibitors ,from which i have calculated % inhibition.

1. i need some help in calculation of IC50 using % inhibition values.
2. i need some assistance in drawing linear regression graph using
thanks in advance.

please help me, its very important and urgent for me..please

thanks in advance.

[Babcock_Hall]

According to the rules of the forum, in order for us to help you, you must first show your attempt at solving the problem.  A good place to start might be to write out the equation that you intend to use and to provide the data. 

[hypervalent_iodine]

Do you have access to Prism / Graphpad?

[Babcock_Hall]

As a generalization, nonlinear regression has some advantages over transformations into linear form (Lineweaver Burk, Eadie Hofstee, etc.).  However, as a means of finding a preliminary estimate of the IC50, the linear transforms are at least adequate in my opinion.