Rat-renin assay suits high-throughput screening

Using 5-FAM/QXL 520 fluorescence resonance energy transfer (FRET) peptide, the assay is suitable for high-throughput screening of renin inhibitors and for continuous assay of rat renin activity.

In the intact FRET peptide, the fluorescence of 5-FAM is quenched by QXL 520.

Upon cleavage into two separate fragments by rat renin, the fluorescence of 5-FAM is recovered and can be monitored at excitation/emission = 490/520 nm.

With a high-fluorescence quantum yield and long emission wavelength, the signal of 5-FAM can be detected with less interference from the autofluorescence of cell components and test compounds.

The assays are performed in a 96-well microplate format and can be adjusted to 384-well microplate format.

The renin-angiotensin system (RAS) plays a central role in the regulation of blood pressure and electrolyte homoeostasis.

At the first and rate-limiting step of the RAS cascade, renin, a highly specific aspartyl protease, cleaves angiotensinogen, produced in the liver, to yield angiotensin I, which is further converted into angiotensin II by ACE (Angiotensin Converting Enzyme).

Angiotensin II constricts blood vessels leading to increased blood pressure.

It also increases the secretion of ADH and aldosterone, and stimulates the hypothalamus to activate the thirst reflex.