The purification and characterization of m-calpain from ostrich brain
2002
Mkwetshana, N. | Naude, R.J. | Oelofsen, W. | Muramoto, K. | Naganuma, T.
Calpains are intracellular cysteine proteases activated in a Ca2+-dependent manner. The purpose of the present study was to investigate the physico-chemical and kinetic properties of ostrich brain m-calpain. m-Calpain was purified by successive chromatographic steps on Toyopearl-Super Q 650s and Pharmacia Mono Q HR 5/5 columns. A Ca2+ concentration of 5 mM and a casein concentration of 5 mg/ml were found to be necessary for optimum calpain activity. Ostrich m-calpain exhibited a Mr of 84 K using SDS-PAGE and a Mmin of 79.3 K from amino acid analysis. The pH and temperature optima were found to be 7.5 and 37 degrees C, respectively. The amino acid composition of m-calpain revealed 700 residues. The N-terminal sequence of m-calpain showed sequence identity with chicken (27%), human (23%) and rabbit (18%) and Schistoma mansoni (9%).
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