[Study on the physicochemical properties of Campylobacter jejuni enterotoxin]

Precipitate of Campylobacter jejuni cytotonic enterotoxin(CE) performed in an 80% saturated solution of ammonium sulfateit indicated that there were some little molecular proteins except the 68 kD main band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE), whereas the eluate from GM1 ganglioside affinity column chromatography exhibited only one 68 kD band on SDS-PAGE. The results suggest that CE mainly be consisted of 68 kD protein. The toxin is heat-labile, pH dependent and resistant to trypsin, It could be completely inactivated by heating at either 56 degrees C and 60 degrees C for 30 min or 100 degrees C for 15 min. The activity was maximum at pH 6.0 and was completely inactivate at pH 3.0 and pH 9.0, and rapidly reduced after storage over 3 d at 4 degrees C. The anti-LT serum could completely inhibited the activity of CE.