Substrates for measuring the chymotryptic, PGPH, and tryptic acitivity of the 20S or 26S proteasome. See also the thrombin substrate I-1140.

Z-GGR-βNA, sensitive chromogenic substrate for trypsin. Furthermore, this substrate allows a distinct histochemical localization of enteropeptidase with the trypsinogen method. It is also cleaved by neutral endopeptidase 24.5. Z-GGR-βNA is also used for determining the tryptic activity of the 20S proteasome.