Immobilization of SpA :: EcoRI on IgG support improves the thermal stability of restriction activity

A plasmid-harbouring E. coli JM109 (3P) strain was cultivated for the overp roduction of the genetically engineered fusion protein SPA::EcoRI. The fusi on protein could be affinity bound selectively and directly from the 25-50% ammonium sulphate fraction of the lysate of E. coli JM109 on to IgG Sephar ose. The preparation obtained thus exhibited high restriction activity on l ambda DNA and linearized the plasmids pBR322 and pUC19. As compared to the native EcoRI the activity of the immobilized preparation was more resistant to thermal inactivation. (C) 2001 Elsevier Science Ltd. All rights reserve d.