These models are only implemented for sedimentation equilibrium data.

mixed association: incompetent species are incompetent for both monomer-dimer and heterogeneous association

* log or lg means log10

* a species not participating in the association can be specified (check the 'add non-participating species' field) This is simply an additional component, perhaps an impurity, which has nothing to do with the associating molecules.

1) Monomer-Dimer A, A2 binding B, forming heterogeneous complexes AB, AAB, and BAAB

with K_{A12}: monomer-dimer association constant (microscopic =
macroscopic)

K_{AB}: microscopic heterogeneous binding constant of B to A

a_{A}: macroscopic cooperativity
constant of K_{[AA]B}/K_{AB}, i.e. enhancement of AB interface
through the dimerization of A. If there's no microscopic cooperativity here, the
macroscopic value of this parameter is the statistical factor 2 (or log10(a_{A})
= 0.30103).

a_{A}^{M}: macroscopic
cooperativity constant K_{[BAA]B}/K_{[}_{AA]B}, i.e.
enhancement of binding of the second B to the free A of a preformed AAB complex
through the presence of a prior B (either via B-B interactions, or modifications
of the free protomer of A in the AAB complex) (microscopic = macroscopic).
If there's no microscopic cooperativity here, the macroscopic value of this
parameter is the statistical factor 1/4 (or log10(a_{A}^{M})
= -0.60206).

1) Monomer-dimer A, A2, and monomer-dimer B, B2, forming heterogeneous complexes AB, AAB, BBA, and BAAB

with K_{A12}: monomer-dimer association constant of A (microscopic =
macroscopic)

with K_{B12}: monomer-dimer association constant of B (microscopic =
macroscopic)

K_{AB}: microscopic heterogeneous binding constant of B to A

a_{A}: macroscopic cooperativity
constant of K_{[AA]B}/K_{AB}, i.e. enhancement of AB interface
through the dimerization of A. If there's no microscopic cooperativity here, the
macroscopic value of this parameter is the statistical factor 2 (or log10(a_{A})
= 0.30103).

a_{B}: analogous to a_{A}
- macroscopic cooperativity constant of K_{[}_{BB]A}/K_{AB},
i.e. enhancement of AB interface through the dimerization of B. If there's no
microscopic cooperativity here, the macroscopic value of this parameter is the
statistical factor 2 (or log10(a_{B}) =
0.30103).

a_{A}^{M}: macroscopic
cooperativity constant K_{[BAA]B}/K_{[AA]B}, i.e. enhancement of
binding of the second B to the free A of a preformed AAB complex through the
presence of a prior B (either via B-B interactions, or modifications of the free
protomer of A in the AAB complex). If there's no microscopic cooperativity here,
the macroscopic value of this parameter is the statistical factor 1/4 (or log10(a_{A}^{M})
= -0.60206).

a_{B}^{M}: macroscopic
cooperativity constant K_{[BBA]A}/K_{[BB]A}, i.e. enhancement of
binding of the second A to the free B of a preformed BBA complex through the
presence of a prior A (either via A-A interactions, or modifications of the free
protomer of B in the BBA complex). If there's no microscopic cooperativity here,
the macroscopic value of this parameter is the statistical factor 1/4 (or log10(a_{A}^{M})
= -0.60206).

There is the relationship:

All models provide the possibility of adding an additional species that is unrelated to the reactive species.

This can be used to describe, for example, a contaminant, or IF signals from sedimenting buffer salts. The presence of such components, and their estimated molar mass and s-value may be obtained from c(s) analysis with sedfit. The purpose of the vbar in this section allows this species to be used in a flexible way in density contrast experiments (e.g. to describe the free detergent micelle).