Table 2.

Potency of Inhibitors Toward a Range of Gut Microbial GUS Enzymes.

Loop Class	GUS	Inhibitor 1 (IC50, nM)		UNC10201652 (IC50, nM)
		pH 6.5	pH 7.5	pH 6.5	pH 7.5
L1	E. coli	2000 ± 200	1900 ± 100	310 ± 20	100 ± 8
L1	E. eligens	ND	ND	1900 ± 100	410 ± 30
L1	S. agalactiae	>25000	>25000	450 ± 30	133 ± 3
L1	C. perfringens	ND	ND	160 ± 10	26 ± 3
L1	F. prausnitzii	ND	ND	ND	>3000
L1	L. rhamnosus	ND	ND	ND	ND
L1	R. gnavus	ND	ND	ND	ND
mL1	B. fragilis	ND	ND	ND	ND
L2	B. uniformis	ND	ND	ND	ND
mL2	P. merdae	NM	NM	ND	NM
mL1,2	B. ovartus	NM	NM	NM	NM
NL	B. dorei	ND	ND	ND	>25000

Uncertainties for IC₅₀ values in nM are presented as the average of 3 biological replicates and errors are SEM. ND means not determined because no inhibition was observed up to 100 µM. NM means not measured because these enzymes showed k_cat values for pNPG cleavage of less than 1 sec⁻¹.