a simple logo of IC50_Ki_Converter
The IC50-to-Ki converter computes Ki values from experimentally determined IC50 values for inhibitors of enzymes that obey classic Michaelis-Menten kinetics and of protein-ligand interactions (Cer, Mudunuri, Stephens & Lebeda (2009)).

IC50-toKi converter (Enzyme-Substrate-Inhibitor System)

Please use the default enzyme concentration [E], substrate concentration [S], Michaelis-Menten constant Km, and IC50 to convert to Ki value OR enter your own value.

CLASSIC INHIBITOR EXAMPLE (botulinum neurotoxin type A) - Ref Burnett et al. 2007

Enzyme concentration, [E] : All units in µM
Substrate concentration, [S] :  
Michaelis-Menten constant, Km :  
Inhibitor concentration to produce 50% inhibition, IC50
  1. Tight-binding inhibitor (monoamine oxidase A) - Ref Fowler CJ and Strolin BM 1983
  2. Complex and potentially cooperative inhibitor (CYP3A4) - Ref Marechal JD et al. 2006

Links: Ki Calculator For Fluorescence-Based Competitive Binding Assays, University of Michigan