Abstract
An extracellular endo poly(β-D-1, 4-mannuronide) lyase of Dendryphiella salina IF 32139 was purified to homogeneity by Q Sepharose FF and Sephacryl S-200 HR column chromatographies. The purified enzyme had a molecular weight of 35, 000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and an isoelectric point of 3.65 by isoelectric focusing. The optimum pH and temperature for enzyme activity were pH 5.0 and 45°C, respectively. The enzyme was stable from pH 4 to 10 and at temperature below 40°C. Some divalent cations, Ca2+, Mn2+, and Zn2+, increased the enzyme activity. Hg2+ and NBS strongly inhibited the activity. This enzyme susceptibly degraded poly-M, produced a wide range of 4, 5-unsaturated oligomannuronic acids, and further degraded these unsaturated oligomannuronic acids to produce the unsaturated monomer and dimer as final products.
