Two GH16 Endo-1,3-β-D-Glucanases from Formosa agariphila and F. algae Bacteria Have Complete Different Modes of Laminarin Digestion

There is a comparative analysis of primary structures and catalytic properties of two recombinant endo-1,3-β-D-glucanases from marine bacteria Formosa agariphila KMM 3901 and previously reported F. algae KMM 3553. Both enzymes had the same molecular mass 61 kDa, temperature optimum 45 °C, and comparable ranges of thermal stability and Km. While the set of products of laminarin hydrolysis with endo-1,3-β-D-glucanase from F. algae was stable of the reaction with pH 4–9, the pH stability of the products of laminarin hydrolysis with endo-1,3-β-D-glucanase from F. agariphila varied at pH 5–6 for DP 2, at pH 4 and 7–8 for DP 5, and at pH 9 for DP 3. There were differences in modes of action of these enzymes on laminarin and 4-methylumbelliferyl-β-D-glucoside (Umb), indicating the presence of transglycosylating activity of endo-1,3-β-D-glucanase from F. algae and its absence in endo-1,3-β-D-glucanase from F. agariphila . While endo-1,3-β-D-glucanase from F. algae produced transglycosylated laminarioligosaccharides with a degree of polymerization 2–10 (predominately 3–4), endo-1,3-β-D-glucanase from F. agariphila did not catalyze transglycosylation in our lab parameters.