Angiotensin-Converting Enzyme (ACE) is an important protein in the body that helps regulate blood pressure. It converts a hormone called angiotensin I into angiotensin II, which narrows blood vessels and increases blood pressure. This process is part of the renin-angiotensin system, a key mechanism for maintaining cardiovascular health. ACE is also a target for certain medications, known as ACE inhibitors, which are used to treat high blood pressure and heart failure. By blocking ACE, these drugs help relax blood vessels, making it easier for the heart to pump blood and reducing the risk of complications related to hypertension and heart disease.