When the detergent is introduced into the lysate, its molecules insert themselves in the lipid membrane and begin separating the lipid bi-layer. As the detergent's concentration increases, the lipid bi-layer becomes saturated with detergent molecules and then starts breaking apart producing protein-detergent complexes and detergent-lipid micelles in the process.
It is interesting to note that while detergents start to form highly organized spherical structures (micelles)in aqueous solutions, as it reaches its Critical Micelle Concentration (CMC), they tend to form reverse micelles in non-aqueous solutions and/or in the presence of hydrocarbon solvents instead.
In general, detergents can be classified as follows:
Ionic.Ionic detergents are ideally used for completely disrupting the cellular structure as well as for denaturing a wide variety of proteins for separation during gel electrophoresis. Some of the most commonly used ionic detergents include the anionic detergents sodium dodecyl sulfate (SDS) and deoxycholate, and the cationic detergent hexadecyltrimethylammonium bromide(CTAB).
Non-ionic.Non-ionic detergents have an uncharged hydrophilic head group and are usually based on polyoxyethylene and/or glycoside. Due to their non-denaturing properties, these detergents are commonly used in isolating biologically active membrane proteins and are most effective in breaking lipid-lipid and lipid-protein interactions. The Triton, Tween and Brij series are great examples of polyoxyethylene-based non-ionic detergents while octyl beta-glucoside and the MEGA series detergents are perfect examples of glycoside-based non-ionic detergents.
