Chemical. CAS: 94367-21-2. Formula: C40H53N5O10. MW: 763.9. Fluorogenic substrate for measuring the chymotrypsin-like peptidase activity of the 20S proteasome, calpains and other chymotrypsin-like proteases. Extinction: 380nm. Emission: 460 nm. This substrate is useful for inhibitor screening and kinetic analysis. - Fluorogenic substrate for measuring the chymotrypsin-like peptidase activity of the 20S proteasome, calpains and other chymotrypsin-like proteases. Extinction: 380nm. Emission: 460 nm. This substrate is useful for inhibitor screening and kinetic analysis.