Schematic diagram of ACE. The illustrations represent an ACE gel before and after
electrophoresis. A labeled PG, loaded into the top horizontal slot, migrates through
lanes containing the test ligand at various concentrations, embedded in 1% low melting
point agarose. The extent to which the PG migration is retarded, as a function of
ligand concentration, can be used
to calculate the dissociation constant Kd for the interaction. If the concentration of labeled PG is
much less than Kd, the value of Kd may be calculated from the equation R = R¥/(1+ Kd/[P]) where R is the retardation
coefficient, calculated as m,
the amount of retardation, divided by n, the distance that unimpeded PG travels, R¥ is the value of R approached at saturating ligand concentrations.
[P] is the concentration of the ligand embedded in each lane. Reprinted with the
permission of author (Herndon and Lander 1997).