I am investigating the strength of binding of a small peptide to a protein by isolating the bound version and subjecting it to collisions with gas molecules (CID mass spectrometry) to dissociate the complex. When I plot the collision energy against the proportion of bound and unbound proteins I get a curve that looks like a Kd curve. However, as the interaction isn't in equilibria (i.e. it is in the gas phase) calculating the Kd value wouldn't be correct.
So is there another value I could calculate to describe the strength of the interaction?