We have some interactions where the responses increases with higher analyte concentrations instead of leveling out towards RMax. The response goes far above the calculated Rmax. We looked for aggregates in the analytes but found none. The binding curves look normal.
It is possible to fit the individual curves to a 1:1 model. But when attempting a fit with all four curves the whole messes up due to the Rmax.
Has anyone an idea whats going on or how to solve this?
Is it because you get high response due to rebinding or non-specific binding on the surface ?
How did you check whether aggregates are formed or not (I mean visual inspection or with some instrument)?