Protein Standards & Ladders for Gel Electrophoresis

Protein standards for SDS-PAGE, western blots, and IEF

A variety of protein standards is available for protein electrophoresis applications. Each standard is supplied in a ready-to-use format, eliminating the need to reduce, pre-mix, or add loading dyes. These standards are consistent from lot to lot and are strictly quality controlled on appropriate gels to help ensure consistent band migration and intensity. All prestained standards are compatible for use in western blotting.

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Prestained and unstained protein standards for SDS-PAGE

In general, unstained standards typically provide a better estimation of size than pre-stained standards. However, pre-stained standards are ideal for confirming the electrophoresis run and estimating the efficiency of transfer onto a membrane. In both cases, the proteins have been modified and stabilized for use in electrophoresis. This often means that their apparent molecular weights are different from that of the proteins in their native state. With pre-stained standards, the difference between native and apparent molecular weights may be greater as proteins have been saturated with dye to ensure consistent migration. In addition, pre-stained standards may also appear less sharp than unstained standards. Therefore, we recommend unstained standards for the most accurate molecular weight estimation, and prestained standards for confirming migration and estimating blotting efficiency.

Selection table for prestained and unstained protein ladders

The bars in the following figure indicate the ranges of each product listed at the left side. Diamonds indicate the location and color of protein bands in each protein ladder.

Size range chart of most popular protein ladders for gel electrophoresis

Featured protein standards categories

Our Western blotting Protein Standard allows direct visualization of protein standard bands on a blot without the need for protein modification or special detection reagents.

We offer various protein ladders for measuring and detecting specialty proteins, such as His-tagged fusion proteins, fluorescence tagged proteins, phosphorylated proteins and glycoslyated proteins.

Our IEF and Native Protein Standards are designed for applications that demand flexibility for native electrophoresis conditions and resolution at either high or low pH.

Our prestained standards provide sharp bands that are easily visualized for simple identification and monitoring of your proteins during electrophoresis.