Binding of d-mannose-containing glycoproteins to d-mannose-specific lectins studied by surface plasmon resonance

Binding of selected glycoproteins containing α-d-mannose sites (invertase, glucoamylase, transferrin, glucose oxidase, and albumin α-d-mannopyranosylphenyl isothiocyanate) with two lectins selective for α-d-mannose branching glycans, concanavalin A (ConA), and Lens culinaris agglutinin (LCA) was studied on lectin biochips by microfluidic surface plasmon resonance (SPR). Lectin-containing biochips were prepared by covalent immobilization of lectins on a flat carboxymethylated gold surface. Both measurement as well as regeneration conditions were optimized. The determined dissociation constants of lectin–glycoprotein interactions were 10−5 to 10−7 mol/l. Dissociation constants KD of studied bindings were estimated by the steady state specific binding models based on both a binding to one site and the multiple binding sites model using Hill slope.