PMC

Three-dimensional structure of nattokinase. (A) Calcium binding site of nattokinase. (B) Three-dimensional structure of nattokinase. (C) Nattokinase triple catalyst. Nattokinase structure diagram taken from https://www.rcsb.org/structure/4DWW with modifications (accessed on 14 March 2012).

(A) Degradative effects of nattokinase in dose-dependent manner. Serial diluted nattokinase (32 µg/mL, 8 µg/mL, 2 µg/mL, 500 ng/mL, 125 ng/mL, 31.25 ng/mL, and 7.8125 ng/mL) were mixed with S protein expression cell lysate and incubated. Full length of S protein (S1 and S2 subunits) and S2 subunit were detected as upper and lower bands, respectively. Ratio of total S was indicated as the relative quantity of S protein (S protein + S2 protein). (B) Degradative effects of nattokinase in time-dependent manner. S protein expression cell lysate was incubated with 1 µg/mL nattokinase for 0, 10, 30, 60, 120, and 180 min. (C) Effects of heating treatment or protease inhibitors. Lane 1: HEK293 lysate; lane 2: HEK293 lysate (S protein); lane 3: HEK293 (S protein) + nattokinase (5 µg/mL); lane 4: HEK293 (S protein) + nattokinase (5 µg/mL) + Protease inhibitor I; lane 5: HEK293 (S protein) + nattokinase (5 µg/mL) + Protease inhibitor III; lane 6: HEK293 (S protein) + heat-treated nattokinase (5 µg/mL). (D) Degradative effect on RBD of S protein and ACE2. RBD of S protein and ACE2 coding plasmids were transfected with HEK293 cells, respectively. Cell lysates were incubated with nattokinase (7.5 µg/mL) and heat-treated nattokinase (7.5 µg/mL) and Western blotting was performed.

Effects of fermentation conditions on the production of nattokinase. (a) Nattokinase activity of PSP2 in media with different oyster protein hydrolysate additions. (b) Nattokinase activity of PSP2 in media with different carbon sources. (c) Nattokinase activity of PSP2 in media with different maltose additions. (d) Nattokinase activity of PSP2 in media with different initial pH. (e) Effect of fermentation time on the production of nattokinase by PSP2 (p < 0.05). Different lowercase letters in the figure indicate significant differences between values.

Effects of nattokinase (A) and tissue-type plasminogen activator (t-PA; B) on the carotid artery thrombosis induced by FeCl₃ application outside the arterial wall. Nattokinase or t-PA were intravenously injected 5 min after FeCl₃ exposure. ○: vehicle (phosphate-buffered saline), ▽: 25 mg/kg nattokinase or 5 mg/kg t-PA, □: 50 mg/kg nattokinase or 7.5 mg/kg t-PA; ◇: 75 mg/kg nattokinase or 8.5 mg/kg t-PA, △: 100 mg/kg nattokinase or 10 mg/kg t-PA