Does BSA protein affect SPR analysis?

Hello,

I am going to buy a protein to use for ligand binding
(GLC chip - CM5 in biacore).
The datasheet states that the reconstitution should be performed at PBS containing 0.1% BSA.
I am worried that I have never used BSA before.

Does the BSA protein 0.1% affect the results?

I have another option, His-tagged protein.
It would be better than BSA?

I wonder how I can solve it.

Thanks for reading.

Hi,

If your analyte is in 0.1% BSA, you can add 0.1% BSA to the running buffer and dilute the analyte in running buffer. This will lower bulk refractive index jumps due to buffer differences.
If and how the BSA will affect the interaction (ka, kd) is hard to say. In general not. BSA is generally added to lower sticking of the proteins to vials and tubing.

The HIS-tagged protein requires another type of sensor chip if you want to use the HIS-TAG. You can of course immobilize the HIS-tagged protein with the amine protocol.

I would go for the purest protein (or the cheapest)

Kind regards
Arnoud

Dear Arnoud,

Thanks for your answering!

Actually, I want to buy protein which contain 0.1% BSA for using ligand immobilization.

I'm really concerned that 0.1% BSA will affect ligand immobilization.

After activation, if BSA attacted to the CM5 chip surface, immobilization seems to be difficult. I wonder if it is possible to use a protein containing 0.1% BSA as a ligand.

Thanks for reading and answering.

Ah, my mistake, did not read the question properly.

All the proteins in the ligand mixture will immobilize to your sensor chip if you use amine coupling. This will lower the efficiency and it will be difficult to determine how much of your ligand is immobilized.
In addition don't add BSA (proteins) to the running buffer during immobilization.

In your case I would buy the His-tagged, since the BSA will interfere with the amine coupling.

Arnoud