Hello all, Does anyone know a method to isolate supercoiled plasmid DNA without making use of a CsCl gradient? This DNA will be used as substrate in a deoxyribonuclease assay (0,1 to 1 mg would be desirable). Thanks. -- J. Martinez-Irujo Departamento de Bioquimica Universidad de Navarra Pamplona, Spain e-mail: jjmirujo at unav.es