Z-Phe-Tyr(tBu)-diazomethylketone is an inhibitor of cathepsin L (Kinact = 200,000 M-1s-1).1,2 It is selective for cathepsin L over cathepsin S and cathepsin B (Kinacts = 30 and 10.3 M-1s-1, respectively). Z-Phe-Tyr(tBu)-diazomethylketone is active against bloodstream forms of T. brucei brucei clone 427-221a in vitro (EC50 = 126 μM).3
References
1. Shaw, E., Mohanty, S., Colic, A., et al. The affinity-labelling of cathepsin S with peptidyl diazomethyl ketones. Comparison with the inhibition of cathepsin L and calpain. FEBS Lett. 334(3), 340-342 (1993).
2. Kirschke, H., Wikstrom, P., and Shaw, E. Active center differences between cathepsins L and B: The S1 binding region. FEBS Lett. 228(1), 128-130 (1988).
3. Nkemngu, N.J., Grande, R., Hansell, E., et al. Improved trypanocidal activities of cathepsin L inhibitors. Int. J. Antimicrob. Agents 22(2), 155-159 (2003).