Systemic lupus erythematosus: Molecular cloning of fourteen recombinant DNase monoclonal kappa light chains with different catalytic properties

An immunoglobulin light chain phagemid library derived from peripheral blood lymphocytes of three patients with systemic lupus erythematosus was used. Fourteen individual DNase monoclonal light chains (MLChs) were purified by metal chelating chromatography followed by gel filtration. The MLChs demonstrated 1 or 2 pH optima and were inactive after dialysis against EDTA, but could be activated by several externally added metal ions; the ratio of relative activity in the presence of different metal ions; Mg2, mN2 +, and cO2 + being among the best activators of their DNase activity. The DNase activity of some MLChs did not require K+ or Na+, while the others could be activated by KCl or NaCl at optimal concentrations from 1 to 100 mM.124