TABLE 3.

Ionic strength dependence of ZPI and cZPI interactions with PZ

Binding constants for NBD-ZPI and NBD-cZPI interactions with PZ were determined at varying NaCl concentrations in pH 7.1 Tris buffer at 25 °C by computer fitting of titrations such as those in Fig. 2 as described under “Experimental Procedures.”

[NaCl]	KD
	ZPI	cZPI
m	nm
0.05		5.9 ± 1.0
0.075	2.2 ± 0.4	6.5 ± 2.0
0.10	2.6 ± 0.6	18 ± 3
0.175	9.5 ± 1.0	56 ± 20
0.25	60 ± 2	150 ± 10
0.35	140 ± 15	500 ± 60
0.50	490 ± 20	1000 ± 50