کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4500313 | 1319979 | 2011 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: A method to calculate binding equilibrium concentrations in the allosteric ternary complex model that supports ligand depletion A method to calculate binding equilibrium concentrations in the allosteric ternary complex model that supports ligand depletion](/preview/png/4500313.png)
The allosteric ternary complex model is frequently used in pharmacology to represent the interaction of a receptor R with two ligands A and B. Certain well-known formulas are routinely used to calculate the fractions of the receptor bound at equilibrium with A only, B only, and both A and B. However, it is often omitted that these classical formulas presume that there is no ligand depletion, i.e. that the equilibrium concentrations [A] and [B] of the ligands are well approximated by their total concentrations [A]T and [B]T. We present a calculation method which is applicable without this or any restrictions. The equilibrium concentration [R] of the receptor is implicitly characterized by an equation which is solved with a very simple convergent numerical algorithm. The concentrations [A] and [B] are given by explicit formulas in terms of [R]. The required parameters are the equilibrium dissociation constants KA and KB, the cooperativity factor α, and the total concentrations [R]T, [A]T and [B]T.
► Equilibrium concentrations are calculated without customary assumption that total receptor concentration is infinitesimal.
► An implicit formula characterizes equilibrium receptor concentration and a simple convergent algorithm calculates it.
► Two explicit formulas express equilibrium ligand concentrations in terms of equilibrium receptor concentration.
► Customary method can give substantially incorrect results when total receptor concentration is not negligible.
Journal: Mathematical Biosciences - Volume 232, Issue 2, August 2011, Pages 135–141