Purification and Characterization of a Lectin Isolated from the Submerged Cultivated Mycelium of Grey Polypore Cerrena unicolor (Bull.) Murrill (Aphyllophoromycetideae)

Cerrena unicolor HAI 1095 lectin from vegetatively grown mycelium was isolated and characterized. Two N-acetyl-D-galactosamine- and one galactose-specific lectin fractions were purified from the mycelia of C. unicolor by a procedure consisting of ammonium sulfate precipitation, gel filtration on a Toyopearl HW-55F column, affinity chromatography and gel filtration on Ultrapac TSK G3000 SW. The C2 lectin fraction was effectively inhibited by N-acetyl-D-galactosamine (GalNAc), galactose (Gal), and lactose at minimal concentrations of 0.39, 0.78, and 1.56 mM, respectively. The hemagglutinating activity of the isolated lectin fraction C2 was stable between 4.0 and 7.5 mM of HCl and NaOH and at temperatures up to 50°C. Mg2+, Cu2+, Ba2+, and Fe3+ increased the hemagglutinating activity of the C2 lectin fraction. C. unicolor mycelium grown on malt extract agar medium accumulates high levels of lectin. The fungus produced two lectin fractions with N-acetyl-D-galactosamine specificity and one fraction with galactose specificity. This review reports on a study on lectin accumulation by C. unicolor. It provides further knowledge about new lectin properties and shows that C. unicolor submerged grown mycelium may be an important source of lectin with high yields.