What is SDS polyacrylamide gel electrophoresis?

Probably the most widely used of techniques for analyzing mixtures of proteins is SDS polyacrylamide gel electrophoresis. In this technique, proteins are reacted with the anionic detergent, sodium dodecylsulfate (SDS, or sodium lauryl sulfate) to form negatively charged complexes.

Is SDS a good solubilizing agent for membrane proteins?

SDS is a very effective solubilizing agent for a wide range of polypeptides, including membrane proteins. It has been established that the majority of proteins bind 1.4 g SDS/1 g protein (1) to form negatively charged complexes.

What is the intrinsic charge of a protein in SDS-PAGE?

For SDS-PAGE, however, the intrinsic charge of a protein is of little consequence, as proteins gain a net negative charge due to interaction with SDS. Proteins are denatured and dissociated by boiling in SDS, and optionally a reducing agent, and then applied to the sample wells of a gel. Treated proteins are loaded into wells in the top of the gel.

Which proteins bind SDS-PAGE?

Although the majority of proteins bind SDS in the expected ratio, it is important to realize that proteins containing nonprotein groups (e.g., glycoproteins, phosphoproteins, lipoproteins) can bind varying amounts of SDS, resulting in anomalous mobility and separation artifacts during SDS-PAGE.

How much SDS is bound by a protein?

The amount of SDS bound by a protein, and so the charge on the complex, is roughly proportional to its size. Commonly, about 1.4 g SDS is bound per 1 g protein, although there are exceptions to this rule.