LMW analyte binding signal

Hi,
i am working on kinase-inhibitor interactions. Most of the sensorgrams are just like the attachments. what can i do to get real binding curve.

kinase was immobilized on CM7 chip to a level of ~9000RU (actate 4.5, pI=5.2)
compound started at 100uM, 3 fold serial dilution, injected for 60s at a flowrate of 30ul/min and measured the offrate 300s
running buffer was Hepes buffer with MgCl2 and MnCl2 and 5%DMSO

it seems like no non-specific binding with the control channel. and i am not sure if the kinase still active in low pH actate buffer while amine coupling. if not, what the measured response of top three concentration mean.

thanks in advance for any comments!

Hi,
What are the Mw of the ligand and analyte?
Did you compensate for the DMSO? It seems that there is a bulk jump...
If this is a low affinity interaction you must go higher in analyte concentration to show that there is partial saturation of the ligand ( www.sprpages.nl/sensorgram-tutorial/a-curve ).

Arnoud

Thanks Arnoud！
The ligand is ~57KDa and the analyte is 446Da.
I suppose the CRO did the 4-point solvent correction for the DMSO. We can see from the top concentration that there is a a bulk drift, right?
different compound behaved differently to the same kinase. I will try higher concentration for the analyte to reach a saturation plateau as you suggested, may be will try other surface to get enough active ligand for the compound.

thank you so much!