Together with the water-soluble collagen (Type I) conjugate (Cat# AS-85111), this water-insoluble fluorescent collagen (type I) can be used for fluorometric measurement of collagenase activity. It is heavily labeled with FITC, resulting in almost total quenching of the conjugates fluorescence. Protease-catalyzed hydrolysis slowly yields brightly green fluorescent dye-labeled peptides. The increase in fluorescence intensity is directly proportional to protease activity. Although this fluorescent collagen is more slowly digested by MMP-1 than water-soluble collagen (Cat# AS-85111), it is more specific for the enzyme.