Specificity of the fucose-binding lectin of Pseudomonas aeruginosa

Abstract PA-II lectin of Pseudomonas aeruginosa , purified by affinity chromatography, was examined for its relative affinity to various carbohydrates using equilibrium dialysis and hemagglutination inhibition tests. This lectin was found to exhibit a high affinity for L -fucose and its derivatives. Among them, p-nitrophentl-α- L -fucose was the strongest inhibitor, followed by L -fucose → L -fucosylamine L -galactose → D -mannose →→→ D -fructose. The association constant ( K _a) of L -focuse for PA-II was 1.5 × 10⁶· M⁻¹ and the number of the L -fucose-binding sites per protein subunit was approximately 1. The K _a of D -mannose for PA-II was 3.1 × 10⁻²· M⁻¹ and a value of 0.84 was obtained as the number of its binding sites per mole protein subunit.