Table 2. Inhibition constants (Ki) of MMP14 and MMP9 with N-TIMP2 selective variants.

	Ki* (nM)		Fold change of Ki**
Clone	MMP14CAT	MMP9CAT	MMP14CAT	MMP9CAT	Specificity shift***
N-TIMP2WT	5 ± 1	0.5 ± 0.04
N-TIMP214_17	0.03 ± 0.003	3.58 ± 0.5	170	0.14	1175
N-TIMP214_18	0.024 ± 0.005	1.25 ± 0.2	211	0.41	512
N-TIMP29_1	240 ± 31	0.78 ± 0.02	0.021	0.66	31
N-TIMP29_13	832 ± 44	1.2 ± 0.007	0.006	0.41	68

^*K_i values (nM) of the purified variants were obtained by fitting the experimental data to Morrison's tight binding equation (Eq. 1).

^**Fold change of Ki reflects the ratio between the K_i of N-TIMP2_WT and the K_i of an N-TIMP2 variant.

^***For the MMP14-inhibiting clones N-TIMP2_{14_17} and N-TIMP2_{14_18}, specificity shifts were calculated as the ratio between the fold improvement to MMP14_CAT, as compared to MMP9_CAT (the specificity shift is defined as the fold change of K_i for MMP14/fold change of Ki for MMP9). For the MMP9-inhibiting clones N-TIMP2_{9_1} and N-TIMP2_{9_13}, specificity shifts were calculated as the ratio between the fold of improvement to MMP9 in comparison to MMP14 (the specificity shift is defined as the fold change of K_i for MMP9/fold change of Ki for MMP14).