b'The combination of a lower-pH gel buffer (pH 6.4) and running buffer (pH 7.37.7) leads to a significantly lower operating pH (pH 7.0) during electrophoresis, resulting in better sample integrity and gel stability.Tris-acetate chemistryWith the Tris-acetate system (Figure 3), three ions are primarily involved: Acetate (), the leading ion from the gel buffer Tricine (), the trailing ion from the running buffer Tris (+), the common ion (in both gel and running buffer)This system also operates at a significantly lower pH than the Tris-glycine system, resulting in fewer gel-induced protein modifications.Glycine MES or MOPS Tricine (trailing ion) (trailing ion) (trailing ion)Protein/SDS complex Protein/SDS complex Protein/SDS complex(stacked proteins) (stacked proteins) (stacked proteins)ChlorideChloride Acetate (leading ion) (leading ion) (leading ion)Progression of run Progression of run Progression of runCommon ion is Tris,Common ion is Bis-Tris, Common ion is Tris, present in the gel and running bu\x02ers present in the gel present in the gel and running bu\x03erFigure 1. Tris-glycine gel system. Figure 2. Bis-Tris gel system. Figure 3. Tris-acetate gel system.Gel buffer ions are Tris and chloride (pH 8.7)Gel buffer ions are Bis-Tris and chlorideGel buffer ions are Tris and acetate (pH 7.0)Running buffer ions are Tris, glycine, and(pH 6.4)Running buffer ions are Tris, tricine, and SDS SDS (pH 8.3) Running buffer ions are Tris, MES or MOPS,(pH 8.3)Gel operating pH is 9.5and SDS (pH 7.3) Gel operating pH is 8.1 Gel operating pH is 7.0 Tricine chemistryThe tricine system (not pictured) is a modification of the traditional Tris-glycine gel system that uses a discontinuous buffer system specifically designed for the resolution of low molecular weight proteins in the range of 220 kDa. As a result of reformulating the Laemmli running buffer and using tricine in place of glycine, SDS-polypeptides form behind the leading ion front rather than running with the SDS front, thus allowing for their separation into discrete bands.7'