Electrophoretic identification of calmodulin in rat parotid gland.

A heat-stable extract of rat parotid gland contained a protein the electrophoretic migration of which on SDS-polyacrylamide gel was accelerated by Ca2+. Its apparent molecular weight was about 17 or 20 K in the presence or absence of Ca2+, respectively; it was able to bind Ca2+. These properties are exactly those of purified calmodulin.