Table 2.

KLK affinity matrix for the most relevant endogenous inhibitors. Data for KLKs 9, 10, and 15 were not available. The rating depended on given inhibition constants K_i or IC₅₀ values that are roughly the doubled K_i (○ no inhibition, ● μM, ●● nM, ●●● pM range), or association constants that were also represented (K_ass ≥ 10⁵ M⁻¹ s⁻¹ ●●●, ≤ 10³ M⁻¹ s⁻¹ ●●), otherwise it was chosen according to the description of the respective publication (“strong inhibition” ●●●, etc., ● slow inhibition). * IC₅₀ ** the protease remains active against small molecule substrates, while protein substrates cannot be cleaved anymore.

KLK	Zn2+	α1-AT	α1-ACT	ATIII	α2-AP	PCI	Kallistatin	Other serpins	LEKTI-1	a2M**
KLK1	○	● [171]	○ [196]	○ [196]			●● [308]	●●● [196]		●●● [229]
KLK2	● (3 μM)* [129]	○ [172], [309]	● [205], [172]	●●● (+heparin) [187], [309]	●●● [172], [309]	●●● < 25 pM [129]		●●● PI-6 [204] ●●● PAI-1 [205]		●●● [230] [231]
KLK3	● (24 μM) [134]	●● [175], [176]	●●● [232], [176]	● [187]		●● [192]		●● MNEI [203]		●●● [232]
KLK4	● (15 μM)* [137]	●●● [178]	○ [178]	● [178]	●● [178]			● PAI-1 [155]		● [178]
KLK5	● (4 μM) [15], [144]	○/● [173], [170]	○ [173]	○ [173], [170]	●●● [173], [170]	●●● [170]	○ [170]	●● C1I [170]	●● [218], [219]	● [173]
KLK6	○	● [174]	● [182]	●● [174]	● [174]				●● [63]	○ [174]
KLK7	● (10 μM) [147]	●●● [170]	●●● [170]	○ [170]	●● [170]	●●● [170]	●●● [170]		●● [218], [219]
KLK8	● (3.3 μM) [123]	○ [170]	○ [170]	● [170]	●● [170]	●●● [170]	○ [170]	●●● PI-6 [206]
KLK11		○ [307]	○ [307]	○ [307]	○ [307]	● [170]	○ [170]
KLK12	● (10 μM)* [17]	●/●● [17], [170]	○ [170]	● [17], [170]	●●● [17]	●● [17]	○ [170]	●● C1I [17]		○ [17]
KLK13		○ [170]	○ [170]	● [170]	●● [170]	●●● [170]	● [170]	●● PAI-1 [170]	●● [63]	● [14]
KLK14	● (2 μM) [15], [31]	●● (162 nM) [63], [170]	● (5.6 μm) [63]	●● (198 nM) [63]	●● (130 nM) [63], [170]	●●● [170]	●● [170]	● PAI-1 [63]	●● [63]