2.1. Materials
GdnHCl, p -nitrophenyl acetate, acetone, ethanol, and
hydrochloric acid were purchased from Wako Pure Chemical Industries
(Osaka, Japan). Coomassie Plus (Bradford) AssayTM kits
for measuring the protein concentration were purchased from Thermo
Fisher Scientific K.K. (Rockford, USA). Carbonic Anhydrase from bovine
erythrocytes was purchased from Sigma-Aldrich Co. LLC (St. Louis, USA).
Sylgard184 was obtained from Dow Corning Corp. (Midland, USA), and
cellulose tubes (MWCO 12–14 kDa, pore size 5 nm, thickness 39.2 μm,
diameter 28.6 mm) were purchased from Nihon Medical Science, Inc.
(Tokyo, Japan).