Captopril

BBM vesicles were isolated from the renal
cortex of male Wistar rats using the Mg/EDTA precipitation method
as reported previously.^{25 (link)} The enzyme-mediated
cleavages of the FGK linkages in [¹¹¹In]In-DO3AiBu-Bn-FGK(Boc) and [¹¹¹In]In-DOTA-Bn-FGK(Boc)
were determined according to our previous procedures with slight modifications.^{25 (link)} Briefly, a solution of BBM vesicles (10 μL,
1 mg/mL for [¹¹¹In]In-DO3AiBu-Bn-FGK(Boc)
and 10 mg/mL for [¹¹¹In]In-DOTA-Bn-FGK(Boc)) was incubated
for 10 min at 37 °C before the addition of each ¹¹¹In-labeled derivative (10 μL). After 2 h of incubation at 37
°C, the radiolabeled species in the reaction mixture were analyzed
by RP-TLC (Figure S3). An aliquot of the
reaction mixture was applied to a 10 kDa cutoff ultrafiltration membrane,
centrifuged at 10,000g for 20 min, and the filtrate
was analyzed by RP-HPLC. Similar experiments were performed in the
presence of 1 mM captopril (Fujifilm Wako Pure Chemical Corporation).