Used to measure endothelial nitric oxide synthase (eNOS) activity in human biological samples such as serum, plasma, or tissue lysates. This kit is widely applied in cardiovascular research to assess endothelial function and nitric oxide production, which are critical in studying conditions like hypertension, atherosclerosis, and endothelial dysfunction. It enables researchers to quantify changes in eNOS activity in response to drugs, hormones, or inflammatory stimuli, supporting both clinical diagnostics and pharmaceutical development. The assay is also useful in investigating the role of eNOS in diabetes, ischemia, and other diseases involving vascular regulation.