Fig. 4

Action mode of recombinant VxAly7D. a The action mode was measured according to the changes in absorbance at 235 nm (dotted line) and reduction in viscosity (solid line). One millilitre of enzyme (10 U) was added to 9 ml of substrate solution [0.3% (w/v) high-viscosity sodium alginate, 100 mM NaCl, 20 mM PB, optimal pH], followed by incubation at 30 °C for 0, 1, 5, 10, 30 and 60 min. b The time-dependent changes in absorbance at 235 nm of reaction mixtures by recombinant VxAly7D. A total of 12 U enzyme was added to 1 ml substrate solution [0.3% (w/v) sodium alginate, 100 mM NaCl, 20 mM PB, optimal pH], followed by incubation at 30 °C for 0, 5, 15, 20, 30, 40, 55, 80 and 90 min. c The time-course of sodium alginate degradation by recombinant VxAly7D was determined by TLC. A total of 5 U enzyme was added to 1 ml substrate solution [0.3% (w/v) sodium alginate, 100 mM NaCl, 20 mM PB, optimal pH], followed by incubation at 30 °C for 0 s, 10 s, 30 s, 1 min, 3 min, 5 min, 10 min, 20 min, 30 min, 40 min, or 60 min