What are the different types of agarose gel used in western blot?

In western blotting, agarose gels are composed of two types: the stacking gel and the separating gel. The stacking gel has a slightly acidic pH (approximately 6.8) and contains a lower concentration of acrylamide. This creates a porous gel that doesn't separate proteins well but allows them to form distinct, narrow bands. The separating gel is positioned below the stacking gel, has a basic pH (approximately 8.8) and a higher concentration of polyacrylamide. This results in narrower pores, enabling better separation of proteins based on their size. Smaller proteins move more rapidly through this gel than larger ones.