Polyoxometalates as sialidase mimics: selective and non-destructive removal of sialic acid from a glycoprotein promoted by phosphotungstic acid.

The selective hydrolysis of the glycosidic bond between the terminal sialic acid and the penultimate sugar has been achieved in the alpha-2-HS-glycoprotein (Fetuin-A) in the presence of H3PW12O40, a Keggin type polyoxometalate. A controlled liberation of sialic acid from the glycoprotein could be achieved at pH 3.0 and 37 °C without the destruction of the protein backbone.