The function of Ensembl gene identifier ENSG00000125818 (PSMF1, proteasome inhibitor subunit 1) is as follows. Plays an important role in control of proteasome function. Inhibits the hydrolysis of protein and peptide substrates by the 20S proteasome. Also inhibits the activation of the proteasome by the proteasome regulatory proteins PA700 and PA28. .