Biochemistry of Vibrio cholerae virulence. Purification of cholera enterotoxin by preparative disc electrophoresis

Abstract

Previously developed procedures for cholera enterotoxin purification were not applicable to large scale purification, and these methods resulted in low yields of pure toxin. An efficient scheme has been developed whereby pure cholera enterotoxin can be obtained from 6 to 8 liters of culture supernatant fluid. This method consists of concentration by membrane ultrafiltration followed by gel filtration and cation exchange chromatography. Pure cholera enterotoxin of high biological potency was obtained after a final step of preparative acrylamide gel electrophoresis. The degree of purity of the toxin antigen as well as its biological activity were determined at various steps of purification. This alternate technique for purification is offered because of the widespread interest in cholera enterotoxin as a specific stimulator of adenyl cyclase.