Novex® NuPAGE® SDS-PAGE Gel System

NuPAGE® protein gels are available in two buffer systems: NuPAGE® Bis-Tris Gels and NuPAGE® Tris-Acetate Gels. The NuPAGE® Bis-Tris Gels provide superior separation of small to medium-sized proteins and employ a neutral-pH environment that minimizes protein modification. The NuPAGE® Tris-Acetate Gels are designed to provide optimal separation for large proteins at pH 8.1.  

NuPAGE® Bis-Tris Gels are used in combination with either NuPAGE® MES or MOPS buffer. The NuPAGE® MES Buffer is recommended for resolving small proteins and for samples containing a broad range of protein sizes. The NuPAGE® MOPS Buffer is best for resolving medium-sized proteins.

NuPAGE® Tris-Acetate Gels are used with NuPAGE® Tris-Acetate SDS Running Buffer to resolve high molecular weight proteins (36–400 kDa) under denaturing conditions, or with Novex® Tris-Glycine Native Running Buffer to resolve high molecular weight proteins under non-denaturing (native) conditions.  Figure 2 shows the migration patterns of Sharp Protein Standards on NuPAGE® Bis-Tris Gels using MOPS and MES buffers, and NuPAGE® Tris-Acetate Gels using NuPAGE® Tris-Acetate SDS Running Buffer.

Sample preparation is a crucial step in successful protein analysis. The pH of the traditional Laemmli-style sample buffer changes from 6.8 to 5.2 when heated at 100°C.  This lower pH is known to induce aspartyl-prolyl (Asp-Pro) peptide bond cleavage, which leads to protein degradation. By maintaining a >7.0 pH environment, the NuPAGE® LDS Sample Buffer preserves protein integrity by minimizing this Asp-Pro cleavage. Figure 3 demonstrates that sample integrity is maintained throughout electrophoresis with the NuPAGE® system; protein degradation is seen in samples prepared with Laemmli (Tris-glycine) sample buffer.  The NuPAGE® Antioxidant running buffer additive greatly minimizes protein oxidation during electrophoresis and keeps reduced protein bands sharp and clear.  

Figure 3. Integrity of samples is maintained throughout electrophoresis with the Novex® NuPAGE® SDS-PAGE Gel System (left), compared to samples prepared with Laemmli (Tris-glycine) sample buffer (right).

Increased Gel Stability

The NuPAGE® protein gels are discontinuous SDS-PAGE gel systems that operate in the same way as the traditional Tris-glycine system but are prepared at a lower pH. This neutral-pH environment allows a much longer shelf life (1 year for NuPAGE® Bis-Tris Gels and 8 months for NuPAGE® Tris-Acetate Gels).

Efficient Western Blot Transfer

The NuPAGE® Transfer Buffer maintains neutral pH and prevents reoxidation of reduced samples during protein transfer to a membrane. This avoids sample modifications that can occur at the alkaline pH of traditional transfer buffers and maintains sample antigenicity. NuPAGE® Bis-Tris Gels are able to separate proteins using lower acrylamide concentrations than are required for Tris-glycine gels. This more open gel matrix allows for more efficient transfer of proteins to membranes during western blotting.

Best All-Around Performance

For routine protein separation, use the NuPAGE® SDS-PAGE Gel System for superior performance. In addition, the high-resolution separation and reduced protein modification and degradation properties make this system suitable for even the most demanding applications. Because the same protein separation can be achieved at lower acrylamide concentrations using NuPAGE® Bis-Tris Gels compared to Tris-glycine gels, western blot transfers are also more efficient.