Overexpression and characterization of a recombinant form of rat calcineurin A.

Overexpression of rat recombinant calcineurin A catalytic subunit in E. coli was achieved using a system under control of the T7 promoter. The specific activity of the purified catalytic subunit was suppressed relative to native bovine calcineurin, with the extent of suppression depending upon the choice of substrate. Addition of calcineurin B subunit stimulated phosphatase activity to one third that of native calcineurin. The metal activators Mn2+ and Ni2+ as well as several anion inhibitors affected both native calcineurin and recombinant calcineurin A activity to the same extent. In addition, calcineurin B was required for inhibition by the immunosuppressive complex FK506-FK506-binding protein.