Purification and some properties of an endo-1,4-beta-D-mannanase from a marine mollusc, Littorina brevicula

An endo-1,4-beta-D-mannanase (EC 3.2.1.78) was purified from viscera of a marine mollusc Littorina brevicula. The purified enzyme, with a molecular weight of 42,000, was homogeneous by SDS-PAGE. The amino-terminal sequence starting with Gly was analyzed up to the 30th amino acid. The enzyme was stable from pH about 4.0 to about 9.0 and had its maximum activity at pH about 6.5. The purified enzyme produced M2, M3, M4, and M5 from Codium beta-1,4-mannan. The enzyme activity was greatly inhibited by Ag+, HG2+, Cu2+, and N-bromosuccinimide at 1 mM concentration.