.Chemical.Components.Speciation

Information

Macromolecule speciation in chemical equilibrium

The equilibrium of the conformation reactions of macromolecules can be simplified to the reactions of their selected electro-neutral forms of the selected conformation, because of the law of detailed balance.

The assumptions of this calculation are:

  1. Initial total concentrations of each subunit must be set to the total macromolecule concentration (for the selected conformation).
  2. The charge, enthalpy of formation, entropy of formation and molar volume of each selected independent subunit form is zero.
  3. Subunits are connected to the same solution as the macromolecule.

Equilibrium equation

xm 

the probability of macromolecule(of the selected conformation)

fi = (xi/xm)

the probalitivy of selected independent subunits forms (of the macromolecule in the selected conformation)

xs = xm· Π fi = xm· Π (xi/xm)

the probability of the selected form of macromolecule (composed from selected subunits in the selected conformation)

us = us° + R·T·ln(xm) + ∑ (ui - R·T·ln(xm))

final equation of the equilibrium of electro-chemical potential




Notations

nT

total amount of substances in the solution

nm

total amount of the macromolecule (of the selected conformation) in the solution

ns

amount of the specific form of the macromolecule (of the selected conformation) in the solution

ni

amount of the specific form of the i-th macromolecule(of the selected conformation)'s subunit in the solution

xm = nm / nT

mole fraction of macromolecule (of the selected conformation)

xs = ns / nT

mole fraction of the selected form of the whole macromolecule (composed from selected subunits in the selected conformation)

xi = ni / nT

mole fraction of i-th macromolecule(of the selected conformation)'s subunit form

us°

base chemical potential of the selected form of the macromolecule (composed from selected subunits in the selected conformation)

us = us° + R·T·ln(xs)

chemical potential of the selected form of the macromolecule (composed from selected subunits in the selected conformation)

ui° = 0

base chemical potential of the specific form of the i-th macromolecule(of the selected conformation)'s subunit in the solution

ui = R·T·ln(xi)

chemical potential of the specific form of the i-th macromolecule(of the selected conformation)'s subunit in the solution





For example: If the macromolecule M has four identical independent subunits and each subunit can occur in two form F1 and F2, then the probability of macromolecule form S composed only from four subunits in form F1 is P(S)=P(M)*P(F1)^4.

Revisions

2013-2015 by Marek Matejak, Charles University, Prague, Czech Republic


Generated at 2019-11-14T02:41:06Z by OpenModelicaOpenModelica 1.15.0~dev-9-g34505da using GenerateDoc.mos