eNOS, or endothelial nitric oxide synthase, is an enzyme found in the cells lining blood vessels. It plays a crucial role in producing nitric oxide, a signaling molecule that helps regulate blood flow and maintain vascular health. By promoting the relaxation of blood vessels, eNOS contributes to lower blood pressure and improved circulation. The activity of eNOS is influenced by various factors, including shear stress from blood flow and the presence of certain nutrients. Dysfunction of eNOS can lead to cardiovascular diseases, highlighting its importance in maintaining a healthy cardiovascular system.