A specially formulated cocktail of six protease inhibitors with broad specificity for the inhibition of aspartic, cysteine and serine proteases as well as aminopeptidases. When reconstituted to 1 ml, each vial will contain 100 mM AEBSF.HCl, 80μM aprotinin recombinant (animal-free), 5 mM Bestatin, 1.5 mM E-64, 2 mM leupeptin hemisulfate and 1 mM pepstatin A. One vial is recommended for the inhibition of proteases extracted from 20 g of tissue. For applications that require animal-free reagents and where the use of DMSO is not recommended.