Renin, a highly specific aspartyl protease, cleaves angiotensinogen, to yield angiotensin I. Angiotensin I is further converted into angiotensin II by ACE (Angiotensin Converting Enzyme). Angiotensin II constricts blood vessels leading to increased blood pressure. Discovery of new renin inhibitors for treatment of hypertension is a promising area of research. The SensoLyte® 520 Mouse Renin Assay Kit provides a convenient assay for high throughput screening of renin inhibitors and for continuous assay of mouse renin activity using a 5-FAM/QXL®520 FRET peptide. In the FRET peptide the fluorescence of 5-FAM is quenched by QXL®520. Upon cleavage into two separate fragments by renin, the fluorescence of 5-FAM is recovered, and can be monitored at excitation/emission = 490/520 nm. The kit contains: 5-FAM/QXL®520-based FRET mouse specific renin substrate (Ex/Em=490/520 nm upon cleavage), assay buffer, mouse recombinant prorenin, reagents for conversion of prorenin to renin, inhibitor, fluorescence reference standard for calibration, and an optimized assay protocol.