Table 1.

Library of phosphinic acid peptidomimetics.

Entry	Compd	Structure	ERAP1a	ERAP2b	APNc	CACO2e		Physicochemicalh
			pIC50 ± SEM IC50 (n)d			Papp A:B (×10-6 cm/s)f	ERg	LogD7.4	pKa
1	DG013A 1		6.73 ± 0.04 0.19 µM (17)	5.53 ± 0.03 3.0 µM (15)	8.44 ± 0.07 0.0037 µM (3)	<1.0	NA	1.0	3.6
2	DG013B 2		4.76 ± 0.06 18 µM (5)	4.01 ± 0.09 98 µM (3)	6.65 ± 0.03 0.23 µM (3)	<1.0	NA	1.0	3.6
3	3		4.11 ± 0.03 77 µM (3)	<3.66 >220 µM (3)	5.47 ± 0.05 3.4 µM (3)	<1.0	>12	3.2	5.4
4	17		6.85 ± 0.07 0.14 µM (3)	6.05 ± 0.11 0.90 µM (3)	8.81 ± 0.01 0.0015 µM (3)	<1.0	NA	1.9	3.6
5	18		6.38 ± 0.09 0.41 µM (3)	5.63 ± 0.12 2.4 µM (3)	8.64 ± 0.11 0.0023 µM (3)	<1.0	NA	−1.4	3.3
6	19		6.49 ± 0.11 0.33 µM (3)	5.90 ± 0.07 1.3 µM (4)	8.06 ± 0.07 0.0086 µM (3)	1.5	8	2.2	3.6

See SI for details. NA = not applicable. All assay data were reprocessed using GraphPad Prism 7.04 in duplicate and fit using a four parameter variable slope non-linear regression model to estimate the IC₅₀ under initial rate conditions. ERAP1 and ERAP2 proteins were produced in house, APN was purchased from Sino Biologics. ^aERAP1 (5 nM) was assayed using L-AMC (250 µM), the K_m of L-AMC was estimated to be >400 µM. ^bERAP2 (10 nM) was assayed using R-AMC (10 µM), the K_m of R-AMC was estimated to be 10 µM. ^cAPN (0.96 nM) was assayed using A-AMC (100 µM), the K_m of A-AMC was assumed to be 100 µM. ^dpIC₅₀ = −log IC₅₀ (M) quoted to 2 dp, SEM = standard error of the mean, n = number of independent biological repeats, the IC₅₀ is the geometric mean quoted to 2 sf. ^eCaco-2 data was produced in house using standard methods, the limit of quantification P_app = 1.0 x 10⁻⁶ cm/s, all values are quoted to 2 sf. ^fP_app was calculated under sink conditions using standard methods, A:B = apical to basolateral. ^gER = efflux ratio, calculated from P_appB:A/P_appA:B, an ER could not be determined when P_appB:A<1.0x10⁻⁶ cm/s. ^hLogD_7.4 and pK_a were calculated using Moka 3.1.3, the pK_a describes the phosphinic acid only, all values are quoted to 2 sf.