Table 2. Kinetic Parameters for Unactivated and Activated OMPDC-Catalyzed Decarboxylation of FO^a.

Activator	(kcat/Km)Act M–1 s–1b	Kd (M)c	[(kcat/Km)Act]/Kd M–2 s–1d	IBE (kcal/mol)e
HPif	(1.6 ± 0.4) × 10–4	0.18 ± 0.05	(8.4 ± 0.4) × 10–4	5.2
D,LG3Pg	(7.0 ± 0.7) × 10–4	0.05 ± 0.01	(1.3 ± 0.1) × 10–2	6.8
LG3Pg,h			(9.9 ± 0.2) × 10–4	5.2
DG3Pi			(2.5 ± 0.01) × 10–2	7.2
DE4Pj	(1.9 ± 0.2) × 10–2	0.030 ± 0.003	(6.0 ± 0.2) × 10–1	9.0
DR5Pg			≈3 × 10–5	3.1

^aAt 25 °C, pH 7.0 and I = 0.15 (NaCl). The quoted errors are the standard deviations from the least-squares fits of the data.

^bSecond-order rate constant for breakdown of E·Act·FO to form FU.

^cDissociation constant for the activator.

^dDetermined as described in the text.

^eFragment intrinsic binding energy, calculated as −RTlnK^‡ (eq 3).

^fFigure 3B.

^gSee SI.

^hNo detectable saturation of OMPDC.

ⁱCalculated from eq 2, where (k_Act) = [(k_cat/K_m)_Act]/K_d from Scheme 3A.

^jFigure 3C.