I'm trying to measure the km of MMP2 in the presence of a peptide substrate. I measured the increase of fluorescence at various concentrations of substrate but I encontered some problems with high substrate concentrations. High substrate concentrations cause the saturation of the instrument signal and the increase of fluorescence is no more visible. Lowering the sensibility of the instrument signal could help to solve the problem for high concentrations, but it could be problem for the lower ones.
Do you know how to skip this problem?
Thanks for any help!!