1× assay buffer

Reagent	Final concentration	Volume (total 5 mL)
Hepes, pH 7.4 (1M)	50 mM	0.25 mL
KCl (4 M)	150 mM	0.1875 mL
MgCl2 (1M)	4 mM	0.02 mL
CHAPS (10%)	0.05%	0.025 mL
Glutathione (200 mM)	1 mM	0.025 mL
MQ water		4.4925 mL
Hepes and CHAPS can be stored at 4°C. KCl and MgCl2 can be stored at 22°C–25°C for at least one year. Glutathione should be stored at −20°C to −15°C.