Definition for Sodium dodecyl sulfate
From Biology Forums Dictionary
SDS (sodium dodecyl sulfate) is a detergent (soap) that can dissolve hydrophobic molecules but also has a negative charge (sulfATE) attached to it. Therefore, if a cell is incubated with SDS, the membranes will be dissolved and the proteins will be soluablized by the detergent, plus all the proteins will be covered with many negative charges. So a protein that started out like the one shown in the top part of figure 1 will be converted into the one shown in the bottom part of figure 1. The end result has two important features: 1) all proteins contain only primary structure and 2) all proteins have a large negative charge which means they will all migrate towards the positve pole when placed in an electric field.