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The proteasome inhibitor PI31 competes with PA28 for binding to 20S proteasomes
Author(s) -
Zaiss Dietmar M.W.,
Standera Sybille,
Holzhütter Hergo,
Kloetzel Peter-M.,
Sijts Alice J.A.M.
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)01072-8
Subject(s) - proteasome , chemistry , activator (genetics) , biochemistry , substrate specificity , proteolysis , microbiology and biotechnology , recombinant dna , enzyme activator , enzyme , biology , receptor , gene
PI31 is a previously described inhibitor of 20S proteasomes. Using recombinant PI31 we have analyzed its effect on proteasomal hydrolyzing activity of short fluorogenic substrates and of a synthetic 40‐mer polypeptide. In addition, we investigated its influence on the activation of 20S proteasome by the proteasome activator PA28. PI31 inhibits polypeptide degradation already at concentrations which only partially inhibit fluorogenic substrate turnover and immunosubunits do not influence the PI31 binding affinity. Furthermore our data demonstrate that PI31 is a potent competitor of PA28‐mediated activation.