Table 1. PSMA Inhibitory Activity of Compounds 7a–c, 8a–b, 9a–b, 10, 9a–b, 12, 13a–b, 14, 15, 21a–b, and 22a–b^a.

compd	IC50 (nM)	compd	IC50 (nM)
7a	2.32 ± 0.55	12	0.20 ± 0.11
7b	2.91 ± 0.33	13a	0.99 ± 0.05
7c	2.11 ± 1.01	13b	0.075 ± 0.005
8a	0.64 ± 0.07	14	1.31 ± 0.18
8b	0.46 ± 0.10	15	1.19 ± 0.73
9a	5.24 ± 1.45	21a	0.94 ± 0.26
9b	5.44 ± 2.54	21b	0.15 ± 0.02
10	4.46 ± 1.03	22a	1.11 ± 0.22
11a	0.35 ± 0.01	22b	0.13 ± 0.01
11b	0.28 ± 0.09	16 (DCIBzL)	0.021 ± 0.004

^aInhibition constants of studied compounds were determined using the radioenzymatic assay with [³H]NAAG (radiolabeled at the terminal glutamate) as described previously.²²