Table 2. Preparation of a general protease inhibitor cocktail

Table

Inhibitor	Trial working concentration	Stock (100X) concentration	Recipe	Amount to use^a	Target protease type
AEBSF	<1 mM	20 mM	239.5 mg/10 mL H₂O (100 mM)	4 mL	Serine
EDTA	1-10 mM	100 mM	19 mg/100 mL H₂O (0.5 M)	4 mL	Metallo
Leupeptin	10-100 μM	2 mM	18.9 mg/2 mL H₂O (20 mM)	2 mL	Cysteine/serine
Pepstatin	1 μM	100 μM	6.8 mg/10 mL methanol (1 mM)	2 mL	Aspartic

Data, in part, from Calbiochem (1998).
^aMix the inhibitor solutions and bring to a final volume of 20 mL with H₂O or an appropriate aqueous buffer. The resulting solution (i.e., 20 mL of the 100X protease inhibitor cocktail stock) can be aliquoted into microcentrifuge tubes and stored at -20°C until required.