Identification of calmodulin in new-born rat calvaria.

The extract of new-born rat calvaria was chromatographed on DEAE-cellulose. Calmodulin activity was eluted at 0.3 and 0.4 M NaCl and markedly inhibited by trifluoperazine and W-7, calmodulin antagonists. The fractions with calmodulin activity contained a protein the electrophoretic migration of which on sodium dodecyl sulfate-polyacrylamide gel was accelerated by Ca2+. Its apparent molecular weight was about 18 or 20K in the presence or absence of Ca2+, respectively. With 45Ca-autoradiography, the protein was shown to have a high affinity for Ca2+. Thus calmodulin could be readily identified in new-born rat calvaria.