Table 1.

Observed thermodynamic parameters of EZA binding to hCA XIII in phosphate and TRIS buffers are listed as a function of pH as determined by ITC at 25°C

pH	Kb_obs, M-1	ΔbGobs, kJ/mol	ΔbHobs, kJ/mol	TΔbSobs, kJ/mol	ΔbSobs, kJ/(mol × K)
EZA - hCA XIII binding in phosphate buffer
6.0	1.70 × 107	−41.27	−11.36	29.91	0.10
7.0	1.17 × 108	−46.05	−17.84	28.21	0.09
8.0	4.96 × 108	−49.63	−37.76	11.87	0.04
9.0	3.33 × 108	−48.65	−66.48	−17.84	−0.06
EZA - hCA XIII binding in TRIS buffer
6.0	5.95 × 106	−38.67	−58.20	−19.53	−0.07
7.0	2.10 × 108	−47.50	−59.71	−12.20	−0.04
8.0	8.69 × 108	−51.02	−48.79	2.24	0.01
9.0	2.27 × 108	−47.70	−33.36	14.33	0.05

Both the observed binding constants and enthalpies were highly pH and buffer-dependent. Standard deviations are below 10% for all parameters measured in kJ/mol.