Assay Method Information

Assay Name:  n-Vitro Fluorescence Assay for Identification of Renin-Inhibitory Activity
Description:  In order to identify modulators of renin activity, a continuous enzymatic test was carried out with a synthetic peptide which carries a fluorescent group Edans (=(5-(aminoethyl)aminonaphthalenesulfonate) which is quenched by energy transfer from a Dabcyl (4′-dimethylaminoazobenzene-4-carboxylate) group on the same molecule, in Greiner 384-well microtitre plates. Cleavage of the peptidic substrate by renin causes an increase in the fluorescence intensity. In order to determine the efficacy of substances, the time-dependent increase in the fluorescence intensity in the presence of the substance was compared with the time-dependent increase in fluorescence in the absence of substances. The reference substance used was renin inhibitor 2 (Z-Arg-Arg-Pro-Phe-His-Sta-Ile-His N-Boc-Lys methyl ester Z) (Sigma-Aldrich). The substrate used was renin FRET substrate I (DABCYL-g-Abu-Ile-His-Pro-Phe-His-Leu-Val-Ile-His-Thr EDANS) (Anaspec, Fremont Calif.). The enzyme employed was recombinant human renin (Proteos, Kalamazoo, Mich.) in a final concentration of 10 nM. The test was carried out in 50 mM Mops buffer, 1.5% (v/v) of DMSO, 0.1% (w/v) of Igepal , pH 7.2, 0.5% (w/v) of BSA. 2 μl of each substance solution with serially diluted substance concentration were added to in each case 4 μl of renin solution and incubated at room temperature for 15 min. The reaction was started by addition of 4 μl of substrate solution (final concentration 5 μM). After carrying out a starting-point fluorescence measurement (excitation wavelength 340 nm/emission wavelength 495 nm) using an Envision multilabel reader (Perkin Elmer), the reaction was incubated at 37° C. for 60 min. The amount of peptide fragment cleaved off during the reaction time was subsequently measured by determination of the increase in the fluorescence intensity at 495 nm (excitation wavelength 340 nm).
Affinity data for this assay
 

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