Scientists take advantage of how salt dissolves in water to purify proteins. When
biochemists study the chemistry of the body, they often focus on the proteins, because
understanding how proteins work can help them design new medicines, diagnose
diseases, and understand how genes work. Unfortunately, though, most of the
interesting proteins and other biological molecules of the body are dissolved in the
watery interior of the cell. It can be very difficult to separate one protein from the
thousands of other proteins and molecules.