Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis Sdspage

Unlike DNA, proteins exhibit considerable differences in their overall charge-to-mass ratios.

Depending on pH, their charge can range from basic to anionic and from hydrophobic to hydrophillic, and their shapes can vary from globular to linear with varying degrees of cross-linking. Shapiro introduced electrophoresis in the presence of sodium dodecyl sulfate (SDS) which is an anionic surfactant that is used to solubilize proteins. Proteins are first denatured with SDS which binds to the hydrophobic backbone of proteins in a regular fashion. Almost regardless of the type of protein, 1.4 g of SDS binds to 1 g of protein and solublizes it. In addition, the charge on the SDS overwhelms the charges on the protein. The degree and type of denaturing can also be enhanced by using SDS solutions which also contain urea and/or a thiol such as dithiothreitol (DTT). The complex is now more or less linear with an overall negative charge so all proteins migrate in a single direction. The denatured unknown proteins are then electrophoresed by PAGE in a buffer system incorporating 0.1% SDS. By running a series of known standards in a parallel lane, the technique can be used to derive molecular weight information since there is a fixed relationship between the relative migration distance of SDS-protein complex and the molecular weight of the native protein.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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