The Effect of Ca2+ on the Polymerization of Carp G-Actin

The effect of Ca2+ on the G-F transformation of carp G-actin was examined by both the precipitation method and the ultracentrifugation method. The transformation started at a Ca2+ concentration of 0.06mmol/(g of G-actin) and was completed at the concentration of 0.30mmol/(g of G-actin). This means that 10mol of Ca2+ is necessary for 1mol G-actin to polymerize to Factin. Such a transformation process can be considered to be the nucleation of F-actin, where the G-actin exists as dimer or trimer. Then, the F-actin nuclei may polymerize to form F-actin molecules.