Peanut (<i>Arachis hypogaea</i>)<i> </i>lectin: Use in quantitation of desialylation of glycoproteins

Abstract

A high affinity lectin from an easily available source, peanut (<i>Arachis hypogaea</i>)<i> </i>agglutinin (PNA) which specifically recognizes desialylated versions of sialylated oligosaccharides is a unique tool in glycoconjugate biotechnology. By a single step affinity chromatography on cross- linked guar galactomannan, PNA was purified to homogeneity with 19 times higher

hemagglutinating activity than the sample prepared by existing methods involving defatting with organic solvents. Agglutinating activity of the new preparation remained unchanged for at least 6 months while PNA prepared from defatted seed lost activity within one week. Glycoproteins desialylated to varying degrees were prepared by treating bovine fetuin with 0.1 <i>N </i>H₂SO₄ at 80°C for durations of 10 seconds and above. Enzyme-linked lectin assay of desialylation of differentially desialylated glycoproteins coated on microplates, using horse radish peroxidase (HRP) conjugate of PNA (PNA-HRP), along with sialic content assay revealed that PNA can be used as a quantitative probe for assay of desialylation in sialylated glycoproteins.