This entry includes the beta 1 subunit of the 20S core proteasome complex from fungi (MEROPS identifier T01.010; also known as PRE3). This is a proteolytically active subunit with a caspase-like (or peptidylglutamyl-peptide hydrolysing) activity, cleaving predominantly aspartyl, glutamyl and tyrosyl bonds []. In Dictyostelium discoideum this subunit is known as psmB6 [].