Table 4.

Potencies (as IC₅₀ or K _d) of toxins and their analogues for K_v1.3, and their respective selectivity for other ion channels

Species	Toxin	IC50 or K d for Kv1.3	IC50/selectivity for other ion channels
Buthus martensi	BmKTX 101	0.2 nM	BKCa: no significant inhibitory activity ≤100 nM
	BmKTX‐19 129	0.4 nM	Kv1.1, Kv1.2, Kv7.1, Kv11.1, SKCa2, SKCa3, and IKCa > 1.0 µM
	BmKTX‐196 129	7.3 nM
Stichodactyla helianthus	ShK 131	11 pM	mKv1.1: 16 pM
			rKv1.2: 9000 pM
			mKv1.4: 312 pM
			hKv1.5: >100,000 pM
			hKv1.6: 165 pM
			mKv1.7: 11,500 pM
			mKv3.1: >100,000 pM
			rKv3.4: >100,000 pM
			hKCa4: 28,000 pM
	ShK‐Dap22 131	23 pM	mKv1.1: 1800 pM
			rKv1.2: 39,000 pM
			mKv1.4: 37,000 pM
			hKv1.5: >100,000 pM
			hKv1.6: 10,500 pM
			mKv1.7: >100,000 pM
			mKv3.1: >100,000 pM
			rKv3.4: >100,000 pM
			hKCa4: >100,000 pM
Orthochirus scrobiculosus	OSK1 132	14 pM	Kv1.1: 0.6 nM
			Kv1.2: 5.4 nM
			KCa3.1: 225 nM
	AOSK1 133	3.0 pM	Kv1.1: 0.4 nM
			Kv1.2: 3.0 nM
			KCa3.1: 228 nM
	[Δ36–38]‐AOSK1 133	1.9 nM	Kv1.1: 365 nM
			Kv1.2: no effect
	[Δ1–7]‐AOSK 133	0.1 nM	Kv1.1: 7.9 nM
			Kv1.2: no effect
Anuroctonus phaiodactylus	AnTx103, 134	0.7 nM	Kv1.1: no significant effect at 100 nMKv1.2: 6.1 nM
	N17A/F32T‐AnTx 134	0.6 nM	Kv1.1: no significant effect at 100 nM
			Kv1.2: 9.6 µM
Centruroides elegans	moka1 104	1.0 nM	Kv1.1: 1000‐fold
Leiurus quinquestriatus			Kv1.2: 620‐fold
Buthus occitanus			KCa1.1: no effect
Heterometrus spinnifer	HsTx1 135	29 pM	Kv1.1: 11,330 pM
	HsTX1[R14A] 135	45 pM	Kv1.1: <20% block at 100 nM
	HsTX1[R14Abu] 135	50 pM	Kv1.1: >100 nM

Note: Photographs: Buthus martensi (by Isaac Miller), Stichodactyla helianthus (by Neil DeMaster), Orthochirus scrobiculosus (by Alex Shaffir), Anuroctonus phaiodactylus (by Alice Abela), and Heterometrus spinnifer (by Daniel Maier).