Compound P binds with X to form the complex PX. A series of solutions was prepared with the total P concentration remaining fixed at 1.00 x10-5M in all solutions. Both P and X do not absorb at 437 nm, but PX has an absorption maximum at 437 nm. The following table shows how the absorbance at 437 nm in a 5.00 cm cell depends of [X], using the assumption that [X]is approximately qual to XTbecause XT>>*P+.
|
[X] in M
|
A
|
|
No X added
|
0.000
|
|
0.00200
|
0.125
|
|
0.00400
|
0.213
|
|
0.00600
|
0.286
|
|
0.00800
|
0.342
|
|
0.0100
|
0.406
|
|
0.0200
|
0.535
|
|
0.0400
|
0.631
|
|
0.0600
|
0.700
|
|
0.0800
|
0.708
|
|
0.1000
|
0.765
|
Make a Scatchard plot of ΔA/*X+ versus ΔA in order to find the equilibrium constant K for this binding event.