Subject: model for 3 compound competitive interaction

From: "FLEMMING CASSEE,ZEIST, THE NETHERLANDS" <[email-masked]>
Date: Thu, 16 Mar 1995 15:55:16 -0500 (EST)

I am not sure wether this is the appropriate place to ask my question, but
I'll try...

From the Michaelsi-Menten equations we know that enzyme activities can be
decribed when one know the maximum activity and the affinity constant for
a given substrate.This model can in general be applied to receptor-
mediated effects. Competitive interaction for a receptor can be described by
the equation:

        Ea,b = Ea,max*Kb*[a] + Eb,max*Ka*[b]/(Ka*kb+kb*[a]+ka*[b])

in whcih E is the effect, Ea,max the max. effect, [a] and [b] the concentrations of each compound and K (or k) the affinity constants fro compound a or b.

However, we like to describe the competitive interaction  for three compounds.

Who can help me finding the equation for three-compound interactions??

I am not a member of this list, so please send your answer to:

[email-masked]

Thanks!    Flemming
---------------------------------------------------------------------
Flemming R. Cassee                                tel: +31 3404 44537
Division of Toxicology                            fax: +31 3404 60264
TNO Nutrition and Food Research Institute       [email-masked]
---------------------------------------------------------------------