Purification and Characterization of a Lectin from Dictyophora indusiata Mycelia

  Objective  Physicochemical properties of the physiologically active lectin component in Dictyophora indusiata Fisscher, a popular edible mushroom in China, were studied to determine the medicinal function.

  Method  A lectin compound was isolated and purified from the mushroom mycelia using physiological saline extraction followed by precipitation in a 20%~75 % (NH₄)₂SO₄ solution and purification with DEAE-Sephrose and Sephadex G-100 gel filtration chromatography. Physicochemical properties of the purified mycelial lectin, DIL, were characterized through the analyses of hemagglutination activity, sugar inhibition, pH and thermal stabilities, and interaction with metal ions.

  Results  DIL showed one band in SDS-PAGE and a molecular weight of 43.6 kDa. It could agglutinate the erythrocytes from pigeon, rabbit, duck, and chicken. The hemagglutination on pigeon erythrocytes was inhibited by D-galactose and N-acetyl-amino-glucose. Being heat-unstable, DIL declined in agglutinating activity significantly at 50℃ in 10min. It remained highly active within pH 4.0~8.0 and was affected by Ca²⁺ or Mg²⁺ but not Mn²⁺ or Zn²⁺.

  Conclusion  It appeared that DIL was hemagglutination-active in the presence of Ca²⁺ and/or Mg²⁺ on animal erythrocytes.