TABLE 3. Ionic and nonionic contributions to the interactions of pentasaccharides with native and latent antithrombin at 25°C and pH 7.4.

The number of ionic interactions, Z, and the nonionic affinities, K_D’, were determined from the slopes and y-intercepts, respectively, of double-logarithmic plots of K_D versus [Na⁺] (Fig. 1). The slopes and intercepts ± SE were obtained by linear regression

Pentasaccharide	Antithrombin form	Z	KD ’ (μM)
Normal pentasaccharide	Native	4.4 ± 0.3a	63 ± 30a
	Native	3.8 ± 0.9b	15 ± 17b
	Latent	1.7 ± 0.2b	18 ± 7b
	Cleaved	1.2 ± 0.2b	10 ± 4b
High-affinity pentasaccharide	Native	4.3 ± 0.3c	0.45 ± 0.08c
	Latent	2.2 ± 0.2	2.2 ± 0.5
	Cleaved	3.3 ± 0.1b	3.2 ± 0.4b

^aTaken from (35)

^bTitrations done in the presence of TNS

^cTaken from (36).