| Abstract: | Calcineurin is the only calcium‐ and calmodulin‐dependent protein phosphatase. Calcineurin B is its regulatory subunit with a molecular weight of 19 kD. In order to study the function of calcineurin B subunit alone, we effectively expressed at high levels and purified calcineurin B subunit from Escherichia coli. Approximately 500 mg of electrophoretically pure protein was obtained from 1 liter of culture. Our experiments demonstrated that calcineurin B subunit by itself produces physiological and pharmacological effects. Preliminary cell and immune studies indicated that while calcineurin B subunit has no direct effect on cell growth, it is a valuable immune regulation reagent. The anti‐cancer effect of calcineurin B subunit was remarkable, especially in vivo, since it reduced the ascites and growth of cancer in the mouse and prolonged the life of the mouse with cancer. The toxicity of calcineurin B was negligible according to results from the acute toxicity experiment. The calcineurin B subunit appears to be a significant biological response modifier. Drug Dev. Res. 56:40–43, 2002. © 2002 Wiley‐Liss, Inc. |
