Equations Flashcards
What does the Hill equation show?
it describes the relationship between the partial pressure of oxygen and the oxygen saturation of hemoglobin.
It is used to describe the fraction of a macromolecule saturated by ligand as a function of the ligand concentration.
What is Ehrlich’s Therapeutic Index?
TI = (max non toxic dose)/(min effective dose)
or TI = (Toxic dose 50%)/(Effective dose 50%)
animal studies:
TI = (lethal dose 50%)/(effective dose 50%)
What is the Hill Langmuir equation?
PAR = (A) / (Ka + A)
What is the equation of the Hill plot?
log ( Par / (1-Par) = log (A) - log (Ka)
log ( Par / (1-Par) against log (A) gives a straight line, slope 1.
In practice, the Hill slope is not always constant, and is referred to as nH, the Hill coefficient.
What is the Hill equation?
y = ymax (A^nH) / (EC50 ^ nH + A^nH)
nH is the Hill coefficient. y is the observed response, ymax is the max response to a large concentration of agonist. EC50 is the concentration of A at which y is half maximal.
What is an equation relating efficacy and intrinsic efficacy?
e = epsilon [R]T
epsilon is intrinsic efficacy (the max response to agonist/max response to full agonist at same receptor)
What is the del Castillo & Katz model?
They introduced the idea of an occupied inactive receptor and occupied active receptor with equilibrium constant E.
What is the Gaddum equation?
PAR = [A] / (Ka (1 + [B]/Kb) + [A])
What is the Schild equation?
r -1 = [B] / Kb
r is the concentration ratio
What is pA2?
empirical measure of activity of antagonist
pA2 = -log [B] (r=2)