Fig. 2
Comparison of catalytic characteristics between purified enzyme (Amy-1) (open) and whole cells of recombinant E. coli overexpressing Amy-1 (close). a The tolerance against p-benzoquinone of whole-cell catalyst (gray) and purified Amy-1 (white). The reaction mixture contained 20 OD600 of cell suspension (1.6 U/mL) or 1.6 U/mL of purified Amy-1, 30 mM of HQ, 1.2 M of sucrose, and different initial concentration of p-benzoquinone. b The substrate inhibition of hydroquinone on whole-cell catalyst and purified Amy-1. The reaction mixture contained 5 OD600 of cell (0.4 U/mL) or 0.4 U/mL of Amy-1, 1.2 M of sucrose, and 20 mM (square) or 80 mM (circle) of hydroquinone in 50 mM PBS (pH 7.0). c The effect of different molar ratio of glycoside donor sucrose and glycoside acceptor hydroquinone on whole-cell catalyst and purified Amy-1. Molar ratio: 1:1 (square), 5:1 (circle), 10:1 (up triangle), 15:1 (down triangle), 20:1 (diamond), 40:1 (left triangle). Different molar ratios were prepared by varying the sucrose concentration (30 mM–1.2 M) with constant HQ concentration (30 mM). The reactions were catalyzed by 10 OD600 of cell (0.8 U/mL) or 0.8 U/mL of Amy-1 at 30 °C