EXPRESSION OF BIOLOGICALLY-ACTIVE HUMAN CALPASTATIN IN BACULOVIRUS-INFECTED INSECT CELLS AND IN ESCHERICHIA-COLI

Calpastatin, an endogeneous inhibitor protein acting on calpain (Ca2+- dependent cysteine proteinase), is widely distributed in animal tissue s and cells. Two different expression systems, baculovirus-infected Sp odoptera frugiperda (Sf9) insect cells and Escherichia coli, were used for overexpression of the human calpastatin tagged with N-terminal he xahistidine peptide. Recombinant calpastatin was purified to homogenei ty by nickel ion affinity chromatography and gel filtration separation . Purified recombinant proteins from both systems have similar inhibit ory activity for calpain.