Hi Alexandra Koriath,

Hope that the below information might help you:

1. For the IgG molecule, the agents that can denature it are Mercaptoethanol or DTT (which is added to the sample buffer), combined with heat treatment (boiling). The gel and running buffer composition for SDS-PAGE or Native-PAGE differ in the presence or absence of SDS, respectively, and this difference usually does not significantly affect the change in MW of the protein on the gel during electrophoresis.

2. What kind of Bis-Tris gel you've mentioned about? I know that Thermo-Fisher has both Bis-Tris buffers for SDS-PAGE and Native PAGE. The thing though is: Denaturing or non-denaturing protein depends on the way you treat your protein (sample buffer, heat treatment).

3. According to the SDS-PAGE result from the link you've attached, Thermo-Fisher showed a sample Protein Gel Interpretation so you can compare your results and evaluate the effectiveness of your IgG digestion. The result you need is your non-reduced "protein A flow-through" sample has around 50 kDa, the reduced one has around 25 kDa, and no 50 kDa band (if the reduced sample has a 50 kDa band, your IgG digestion is not good, which means having undigested IgG post-digestion).

Best luck!

Dear Alxandra

at the following link

https://www.blogger.com/video.g?token=AD6v5dyp2LLPNQObE-O7xpUxV02oGcx4RQ0mfxIRjK1x1YHBCYw3Av9JZTXdeO6JXLu6wl6Cd2omOIASqXY7BDpDcvlzrJ8fQSoqXnMyd5Fqcc3vRe-1JCCyISDv7Y-UACmOPKhEV6M

you can find a video (part of mu blog named ProteoCool) with an overview about SDS-page, different buffers and reducing and not reducing approach.

i hope it could be usefull to solve at least some of your doubts!

best regards

Manuele