Elastases catalyze the hydrolysis of elastin, the chief constituent of elastic fibers that together with collagen determines the mechanical properties of connective tissue. Elastases have many other natural substrates these include proteoglycans, collagens and fibronectin. Implicated in many diseases such as pulmonary emphysema, cystic fibrosis, infections, inflammation and atherosclerosis, elastases are considered important drug targets. The SensoLyte® Green Elastase Assay Kit uses natural substrate elastin labeled with the 5-FAM fluorophore and the QXL™ 520 quencher. Proteolytic cleavage of labeled elastin yields brightly green fluorescence, which can be continuously monitored at excitation/emission= 488 nm/520 nm. Increase in fluorescence intensity is directly proportional to elastase activity. This kit does not require any separation steps and can be used to continuously measure the kinetics of elastase activity.