Table 3. Composition of buffer solution for Ni-NTA purification and SDS-PAGE

Buffer solution	Composition
Ni-NTA purification
Wash buffer	6.9 g/L NaH2PO4·H2O, 17.54 g/L NaCl, 20 mM imidazole (pH 8.0)
Elusion buffer	6.9 g/L NaH2PO4·H2O, 17.54 g/L NaCl, different concentrations of imidazole (50, 100, 150, 200, 250 mM)
SDS-PAGE
Staining buffer	1 g/L Coomassie blue R-250, 45% (v/v) methanol, 10% (v/v) glacial acetic acid
Destaining buffer	10% (v/v) methanol, 10% (v/v) glacial acetic acid

Ni-NTA, nickel-nitrilotriacetic acid; SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis.