ILLUSTRATION $15\mathrm{.}4-1$ :

The Binding of Warfarin to Human Albumin

Warfarin, also known as coumadin, is used to prevent blood clots in humans and also, at high body doses $($referred to as a high body burden in the biomedical literature$),$ as a rat poison by promoting internal bleeding. Warfarin binds with human plasma albumin in the reaction

$W+A{}^{K}WA$

The following measured or apparent $($not standard$-$state$)$ data at $25C$ are available for this binding reaction, ${}_{bnd}G=-30\mathrm{.}8kJmo{l}^{-1},{}_{bnd}H=-13\mathrm{.}1kJmo{l}^{-1},$ and ${}_{bnd}{C}_{p}0,$ where these apparent changes are for the following equilibrium constant:

${}_{bnd}G=RTlnK,$ where $,K=\frac{M_{wA}}{M_w*M_A}$

where $M$ is the concentration in molality.

a$.$ What is the entropy change for this reaction at $25C?$

b$.$ Starting with concentrations of warfarin and human plasma albumin of $0\mathrm{.}0001M,$ what is the fraction of unbound $($unreacted$)$ albumin over the temperature range of $0$ to $50C?$