Magnesium sulfate is used in biochemistry and molecular biology as a source of magnesium ions. This element has diverse biological roles in enzymology, structural integrity of the cell membrane and cell wall, muscle cell physiology and nucleic acid structure. Magnesium is an essential cofactor in many enzymes, including deoxyribonuclease (DNase), the restriction enzymes EcoR I and EcoR V, and ribonuclease H. In addition, magnesium stabilizes polymeric nucleic acids such as transfer RNA and ribozymes.