Intrinsic nucleoside diphosphate kinase-like activity is a novel function of the 20 S proteasome

J Biol Chem. 1999 Nov 26;274(48):34375-82. doi: 10.1074/jbc.274.48.34375.


The eukaryotic 20 S proteasome is the prototype of a new family of the N-terminal nucleophil hydrolases and is composed of numerous low molecular mass subunits arranged in a stack of four rings, each containing seven different alpha- or beta-subunits. Among the beta-type subunits in the yeast proteasome, three proteolytically active ones were identified, although the functions of the other beta- and alpha-type subunits remain to be clarified. We report here that the purified 20 S proteasome exhibits intrinsic nucleoside diphosphate (NDP) kinase-like activity. The proteasome exhibited a preference for ATP and dATP as phosphate donors, and a broad specificity for NDPs, other than GDP, as phosphate acceptors, unlike conventional NDP kinase, which catalyzes the transfer of gamma-phosphate between NDPs and nucleoside triphosphates. During the transfer of gamma-phosphate, the proteasome formed acid-labile phosphohistidine as autophosphorylated intermediates, and NDP-dependent dephosphorylation of the latter then occurred. These enzymatic properties are similar to those of the molecular chaperone, Hsp70, which also exhibits intrinsic NDP kinase-like activity, instead of ATPase activity. C5 among the beta-type subunits and C8 among the alpha-type subunits were autophosphorylated during the gamma-phosphate transfer reaction and were photoaffinity labeled with 8-azido-[alpha-(32)P]ATP, suggesting that the C5 and C8 subunits of the proteasome are responsible for the NDP kinase-like activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Diphosphate / metabolism
  • Adenosine Triphosphate / metabolism
  • Amino Acid Sequence
  • Cysteine Endopeptidases / metabolism*
  • Cytidine Diphosphate / physiology
  • Humans
  • Kinetics
  • Molecular Sequence Data
  • Multienzyme Complexes / metabolism*
  • Nucleoside-Diphosphate Kinase / chemistry
  • Nucleoside-Diphosphate Kinase / metabolism*
  • Peptide Fragments / chemistry
  • Peptide Fragments / metabolism
  • Phosphorylation
  • Proteasome Endopeptidase Complex
  • Sequence Analysis, Protein
  • Substrate Specificity
  • Tumor Cells, Cultured


  • Multienzyme Complexes
  • Peptide Fragments
  • Adenosine Diphosphate
  • Cytidine Diphosphate
  • Adenosine Triphosphate
  • Nucleoside-Diphosphate Kinase
  • Cysteine Endopeptidases
  • Proteasome Endopeptidase Complex