Proteasomes are large protein complex located in nucleus and cytoplasm in all eucaryotes. They degrades and recycles the target protein that been tagged by ubiquitin. The tagged protein is hydrolyzes into 7-8 amino acids long peptides that are further degraded. The 20S assembly is the protease structure that has chymotrypsin/trypsin/caspase-like protease activities. This Proteasome Activity Assay utilized the chymotrypsin-like activity with an AMC-tagged peptide substrate that releases free, highly fluorescent AMC in the presence of proteolytic activity. The kit also contains Jurkat Cell lysate as a positive control and MG-132 as proteasome inhibitor. This can differentiate proteasome activity from other protease activities that may also in the samples.