It has been demonstrated that cobra venom factor prepared by the usual combination of ion exchange chromatography and sephadex gel filtration is contaminated by substantial amounts of a 'heavy' phospholipase A. The two activities may be separated by isoelectric focusing. Cobra venom factor focuses at pH between 5-75 and 6-75 whereas the phospholipase is all found at pH below 7-75. In certain test systems, particularly in vitro, and particularly where albumin concentrations are low, the contaminating phospholipase may produce effects that have been attributed to complement activation.
Chromatography, Gel Chromatography, Ion Exchange