Table 2.

Kinetic and affinity parameters calculated for the interaction of active compstatin peptides with human C3.^a

Peptide #	Peptide Name	KD (10−6 M)	Rmax	Kon1 (105/M·s)	Kon2 (10−2/s)	Koff1 (10−2/s)	Koff2 (10−2/s)	χ2	Model
II	Parent	1.26	937.7	0.172	1.40	13.04	0.282	4.69	2-State Reaction
		0.81	507.6	0.036		0.294		12	1:1 Binding
III	W4/A9	0.19	1781	0.558	0.52	6.402	0.106	78.1	2-State Reaction
		0.23	1000	0.129		0.296		813	1:1 Binding
IV	SQ027	0.76	2781.5	0.561	0.36	8.73	0.337	52.27	2-State Reaction
		0.51	1086.2	0.412		2.111		1522.7	1:1 Binding
V	SQ059	0.74	1150	1.051	1.29	74.30	1.289	9.21	2-State Reaction
		0.45	484.9	0.050		0.225		28.3	1:1 Binding
VI	SQ086	0.99	2154	2.091	1.03	84.76	0.326	36	2-State Reaction
		0.50	799	0.085		0.418		181	1:1 Binding
VII	W4/A9/W13	0.74	1397	0.100	0.55	2.184	0.282	23.8	2-State Reaction
		0.70	939.8	0.069		0.483		108	1:1 Binding
VIII	W1/W4/A9	0.50	1516	0.108	0.48	1.146	0.425	6.83	2-State Reaction
		0.52	1297	0.087		0.456		61.4	1:1 Binding
IX	W1/W4/A9/W13	0.38	2442	0.154	1.38	1.534	0.866	41.7	2-State Reaction
		0.38	2187	0.126		0.477		111.3	1:1 Binding

^aThe C3 concentration range used for the fits is 0–800nM.