The ACE inhibitory activity of TRMHs was measured according
to Sentandreu and Toldrá [28]. This assay is based on the ability of ACE
to hydrolyze the internally quenched fluorescent substrate oaminobenzoylglycyl-
p-nitro-L-phenylalanyl-L-proline (Abz-Gly-Phe-
(NO2)-Pro). A sample solution (50 μl) was mixed with 50 μl of
150 mM Tris-base buffer (pH 8.3) containing 3 mU/ml of ACE, then
themixturewas preincubated for 10 min at 37 °C. The reaction was initiated
by the addition of 200 μl of 150mMTris–HCl buffer (pH 8.3) containing
1.125 M NaCl and 10 mM Abz-Gly-Phe-(NO2)-Pro and
preincubated 10min at 37 °C. Finally the reactionmixturewas incubated
for 45min at 37 °C. The generation of fluorescence due to the release
of o-aminobenzoylglycine (Abz-Gly) by the action of ACE was measured
using excitation and emission wavelengths of 355 and 405 nm, respectively.
ACE inhibition is expressed as percentage. The test was carried
out in triplicate.