HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC CHARACTERIZATION OF 2 LICHEN LECTINS WITH ARGINASE ACTIVITY DIFFERING IN THEIR GLYCOSYL MOIETY

Two isolectins from the lichen Xanthoria parietina, one of them retain ed by the thallus and another secreted from the thallus to the medium, both showing arginase activity, have been purified to homogeneity. Et hanol-soluble products obtained after acidic hydrolysis of both protei ns have been analyzed by HPLC under isocratic conditions using acetoni trile-water (80:20, v/v) as mobile phase. Detection is performed by me asurement of UV absorbance at 195 nm, using a highly sensitive detecto r. Purification of standard sugars by filtering aqueous solutions thro ugh an activated alumina column is absolutely required. The glycosyl m oiety of secreted arginase is composed by galactose and glucose wherea s that of thalline enzyme contains N-acetyl-D-glucosamine and glucose.