N-[3- (2-Furyl) acryloyl]-Phe-Gly-Gly (FAPGG) is a specific substrate of angiotensin converting enzyme (ACE) with a Ki of 2.546x10-4 M. It is used as a chromogenic probe for quantitative detection of ACE activity. N-[3- (2-Furyl) acryloyl]-Phe-Gly-Gly can be hydrolyzed by ACE to generate N-[3- (2-furyl) acryloyl]-Phe (FAP) and Gly-Gly, and the ACE inhibitory effect is monitored by photometry. FAPGG competitively binds to the active center of ACE and is a key tool for screening ACE inhibitors such as Captopril and Dioscorin. Its reversible mechanism of action supports hypertension research and drug development targeting the renin-angiotensin system[1].