Table 3.

Interaction thermodynamics of the N-ter octadecapeptide and proteins with heparin and CS-E, studied by ITC

Protein	Polysacch.	ΔGn (kJ/mol)	n protein/polysacch.	ΔGn/n (kJ/mol)	Kd mM
N-ter	heparin	−37	7	−5.3	117
	CS-E	−43	55	−0.78	730
HD	heparin	−32	5	−6.4	75
	CS-E	−44	33	−1.3	591
ExtHD	heparin	−40	3	−13.3	4.5
	CS-E	−41	29	−1.4	568

The proteins were titrated with the polysaccharides at 25 °C in 50 mM NaH₂PO₄, 100 mM NaCl, pH 7.4. The affinity of peptide or protein for the polysaccharide is determined by dividing the free Gibbs energy by n (stoichiometry of the complexes) and calculated as K_d = e^∆G/RT. Data are presented as the mean (n = 3).