Table 3.

Thermodynamic parameters for the binding of ligands to the wild-type phosphatases and their catalytic cysteine mutants

Enzyme	Ligand	Kd (μM)	ΔH (Kcal mol−1)	TΔS (Kcal mol−1)	ΔG
PTP1B WT	Ac-DADE-F2PMP-L-NH2	0.24 ± 0.05	−3.9 ± 0.2	5.1 ± 0.2	−9.0 ± 0.1
PTP1B C215S	Ac-DADE-F2PMP-L-NH2	0.19 ± 0.03	−10.4 ± 0.2	−1.2 ± 0.2	−9.2 ± 0.1
Yersinia PTPase WT	Vanadate	1.3 ± 0.1	−10.0 ± 0.2	−2.0	−8.0
Yersinia PTPase C403S	Vanadate	2.3 ± 0.1	−14.9 ± 0.1	−7.2	−7.7

PTP1B data are from Zhang et al (2000).

Yersinia PTPase data are from Wang et al. (1998).

F₂PMP: difluoro-phosphonomethyl phenylalanine (non-hydrolyzable phospho-tyrosine analog).