Large scale preparation of calmodulin.

A rapid large scale purification procedure based on three conventional purification steps, ammonium sulfate fractionation, DEAE cellulose and hydroxylapaptite chromotography yields gram amounts of calmodulin. The protein is more than 98% pure by SDS gel electrophoresis and amino acid composition. It is free of contaminating EGTA or EDTA and the omission of heat treatment or denaturing solvents during the preparation avoids possible denaturation of the protein and minimizes partial proteolysis.