Table 1.

pK_a of Ionizable Sidechains as Determined by the Nonequilibrium Method and PROPKA for Asp13 and Lys7 in the Apo and Substrate/Product Ternary Complexes^a

Complex	Residue	pKaref	pKaFEP	pKaPROPKA
HepI			4.6 ± 0.3	4.46
HepI•ADP-Hep•FDLA	Asp13	3.9	5.9 ± 0.2	6.79
HepI•ADP•FDHLA			5.9 ± 0.3	10.38
HepI			10.9 ± 0.8	9.27
HepI•ADP-Hep•FDLA	Lys7	10.5	9.5 ± 0.3	8.81
HepI•ADP•FDHLA			9.1 ± 0.4	5.77

^aRed arrows indicate a rise in the pK_a and blue arrows indicate a drop in the pK_a relative to the reference.