What are the commonly used discontinuous gel buffer systems?

Commonly used discontinuous gel buffer systems include:

• Tris-Glycine – Tris-Glycine buffer concentrate is widely used as a transfer buffer for gel electrophoresis and Western blotting. 
• Zymogram – Zymogram gels are essentially Tris-Glycine gels that contain casein or gelatin. They are generally used to characterize and detect proteases that utilize gelatin as a substrate. 
• Tris-Tricine – A modification of the Tris-Glycine gel system, Tris-Tricine is optimized for the separation of peptides and small proteins with a low molecular weight.
• Tris-Acetate – Tris-Acetate gels facilitate the optimal separation proteins with a  high molecular weight during gel electrophoresis. The lower pH of Tris-Acetate gels increases the stability of these gels, which reduces protein modifications and produces sharper bands.
• Bis-Tris – The almost-neutral pH of Bis-Tris gels offers enhanced stability, which minimizes protein degradation. These gels are preferred for applications such as mass spectrometry, sequencing, and posttranslational modifications, where high sensitivity is crucial.