Table 1.

Panel of cationic compounds, polymers, and proteins

Compound	No.*	IC50 (or % inhibition)*
Low MW polyethyleneimine	1	10 ng/mL
Polybrene	2	19 ng/mL
High MW polyethyleneimine	3	35 ng/mL
Generation 3.0 dendrimer		40 ng/mL
Generation 2.0 dendrimer		47 ng/mL
Norspermine		52 ng/mL
Spermine	4	57 ng/mL
Generation 1.0 dendrimer	5	58 ng/mL
Histone H1	6	59 ng/mL
Poly-D-lysine		79 ng/mL
Poly-L-arginine		81 ng/mL
Protamine sulfate	8	0.11 μg/mL
Poly-L-lysine		0.14 μg/mL
Generation 0.0 dendrimer		0.14 μg/mL
Heparin		0.27 μg/mL
Polymyxin B	9	0.38 μg/mL
Histone H2A/H2B dimer		0.38 μg/mL
Histone H2B		0.46 μg/mL
Histone H3.1/H4 tetramer		0.53 μg/mL
Histone H4		0.84 μg/mL
Colistin		0.91 μg/mL
Histones (mixed)		0.93 μg/mL
Histone H2A		1.3 μg/mL
Spermidine		1.7 μg/mL
Histone H3.1		2.5 μg/mL
Human platelet factor 4	10	3.8 μg/mL
PPXbd	11	8.5 μg/mL
Lon protease polyP-binding domain		72 μg/mL
1,3-diaminopropane		0.47 mg/mL
Ethylenediamine		0.89 mg/mL
Norspermidine		(62% inhibition at 200 μg/mL)
1,2-bis(3-aminopropylamino)ethane		(53% inhibition at 200 μg/mL)
Kanamycin		(48% inhibition at 200 μg/mL)
DNase I		(36% inhibition at 200 μg/mL)
RNase A		(23% inhibition at 100 μg/mL)
Bacitracin		(12% inhibition at 200 μg/mL)
Methylenediamine		(73% inhibition at 6 mg/mL)
Ammonium chloride		(44% inhibition at 2.7 mg/mL)
Melamine		(0% inhibition at 200 μg/mL)
Cystamine		(0% inhibition at 200 μg/mL)
Histamine		(0% inhibition at 200 μg/mL)
Histidine		(0% inhibition at 200 μg/mL)

Each substance was tested at 200 μg/mL (or indicated concentrations) for inhibition of thrombin binding to immobilized biotin-polyP. Those exhibiting > 70% inhibition were retested at various inhibitor concentrations, from which IC₅₀ values were derived (listed here in order of decreasing potency).

^*Numbers are the compound numbers used in Figure 2.