Table 1.

Binding characterization of DARPin 8h6 to human and mouse CatB as determined by enzyme inhibition (Fig. 1c and Fig. S4) and surface plasmon resonance (Figs. S5, 6).

	Inhibition			SPR
	Ki [pM]	α	β	ka [M-1 s-1]	kd [s-1]	KD [nM]	χ2 [%Rmax]
Human CatB	34 ± 1	6.6	0.15	2.1 × 106	6.6 × 10-5	0.031	2.2 %
Mouse CatB	35 ± 3	6.1	0.064	7.5 × 105	1.5 × 10-4	0.20	12.5 %
Human proCatB				1.4 × 104	1.0 × 10-4	7.1	3.6 %