Title: Learn: Disulfide Bonds
Course: BTEC-2020-301-302-303-F21 > Section: Protein Gels

Module2 Disulfide Bonds

Disulfide bonds, which can form between the sulfur atoms in cysteine residues, are exceptionally strong, and are generally not disrupted by SDS. To eliminate the shape from disulfide bonds, we treat proteins with DTT (dithiothreitol) or BME (beta-mercaptoethanol).

DTT (dithiothreitol) - a reducing agent that can disrupt disulfide bonds

In the lab, you’ll notice that DTT and BME both smell like sulfur—it’s that sulfur that allows them to disrupt disulfide bonds, eliminating the last traces of tertiary or quaternary structure.

Dithiothreitol (DTT) reduces disulfide bonds, removing the last traces of tertiary or quaternary structure.

The loading dye that is added to protein samples for SDS-PAGE contains both SDS and DTT. After loading dye is added to the proteins, the samples are boiled. Heat causes proteins to denature (lose their native shape). The idea is that, between SDS, DTT, and boiling, essentially no native shape should be left.