IC50: 81 μM (ACE)

Kinetic analyses demonstrate that enalapril inhibits the uptake of GlySar in a competitive manner (K _i approximately 6 mM). Fosinopril and Zofenopril have the greatest inhibitory potency (IC ₅₀ values of 55 and 81μM, respectively) while the other ACE inhibitors exhibit low-affinity interactions with the renal peptide transporter.

Zofenopril, a sulphydrylic compound, at doses higher than 70 mg/kg i.p. produces significant protection (i.e. at 70 mg/kg, P=0.044, F=2.17, d.f.=18; at higher concentration P<0.05) against the tonic phase of the audiogenic seizure response. Pretreatment with Zofenopril (15 mg/kg, i.p.) is able to produce a consistent shift to the left of the dose-response curves and a significant reduction of ED ₅₀ values against clonus of some AEDs with the exceptions of diazepam, felbamate, phenobarbital and phenytoin compare with concurrent groups, suggesting an increase in anticonvulsant activity.