Table 1. Kinetic Parameters of Dipeptide Nitriles 1a and 1b and Dipeptide Alkynes 2a and 2b with Respect to Cathepsins B, S, L, and K^a.

compound	R	CatB	CatS	CatL	CatK
Ki (μM)
1a	F	0.109 ± 0.023	0.406 ± 0.040	0.661 ± 0.011	25.94 ± 0.58
1b	H	0.042 ± 0.003	0.046 ± 0.004	0.220 ± 0.004	8.81 ± 0.17
kinact/KI (M–1 s–1)
2a	F	22 ± 2	58 ± 1	30 ± 3	3 ± 0,1
2b	H	85 ± 3	682 ± 85	281 ± 30	48 ± 5

^aData shown are mean values ± SEM of three experiments, each performed in duplicate.