Reversible inactivation of vibrio cholerae neuraminidase by gangliosides

Vibrio Cholerae neuraminidase binds gangliosides, like monosialoganglioside GM1 (which is resistant to the enzyme action), and disialoganglioside GD1a (which is hydrolyzed by the enzyme), forming lipo-protein complexes. This process is time and temperature dependent and follows saturation kinetics. The neuraminidase-ganglioside complex can also be prepared by ammonium sulfate precipitation. The formation of the complex is followed by enzyme inactivation. However, upon addition of adequate amounts of albumin, the enzyme activity is largely recovered. It is thus evident that Vibrio Cholerae neuraminidase, when binding gangliosides, forms two different complexes: the enzyme-substrate complex, which is the specific one, and another one, probably unspecific, in which the enzyme carries no more activity.