Characterization of an endo-1,3(4)-beta-D-glucanase gene from Cellvibrio mixtus.

An endo-1,3(4)-beta-D-glucanase gene (cwd2) of Cellvibrio mixtus encoding laminarinase activity was cloned on a 3.9-kb PstI fragment. The Cwd2 enzyme, extracted from recombinant Escherichia coli, degraded both beta-1,3 glucans and beta-1,3-1,4 mixed-linkage glucans, was endohydrolytic and so conformed to the enzyme class 3.2.1.6. The pH and temperature optima of the enzyme were approximately 7 and 40 degrees C respectively. The M(r) of specifically labelled Cwd2 was approximately 34,000. This gene was quite distinct from two other C. mixtus beta-1,3 glucanases previously described.