Evidence for a Novel ATP-Dependent Protease from the Rat Liver Mitochondrial Intermembrane Space: Purification and Characterisation.

J-STAGE
  • Sitte Nicolle
    Institute of Biochemistry, Medical Faculty (Charité), Humboldt University Berlin
  • Dubiel Wolfgang
    Institute of Biochemistry, Medical Faculty (Charité), Humboldt University Berlin
  • Kloetzel Peter-Michael
    Institute of Biochemistry, Medical Faculty (Charité), Humboldt University Berlin

抄録

An ATP-dependent protease in the intermembrane space of rat liver mitochondria, MISP I (mitochondrial intermembrane space protease), was partially purified and characterised. The protease complex has a molecular mass of 200 kDa and appears to be an oligomeric enzyme complex. The proteolytic activity of the enzyme can be stimulated up to 3-fold by Mg2+ATP. The Km for ATP is 200 μM. Nucleoside triphosphates, but not ADP, AMP, or nonhydrolysable ATP analogues, can substitute for ATP. The protease exhibits multicatalytic properties with chymotrypsin-like, peptidyl-glutamyl-hydrolysing, and trypsinlike activities. Of the latter the trypsin-like activity is not enhanced by ATP. In addition to the hydrolysis of fluorogenic peptide substrates the protease is able to degrade radiolabeled model proteins. The ATP-dependent mitochondrial protease was characterised as a cysteine protease sensitive to hemine. The cross reactivity of an anti-human-S4 antibody raised against an ATPase subunit of the PA700 complex with a component of MISP I indicated a structural relationship. Furthermore, ATP-agarose-binding assays revealed the connection of the peptide hydrolysing activity with an ATP binding domain. The data presented here and a comparison with known ATP-dependent mitochondrial proteases demonstrated that MISP I represents a novel ATP-dependent protease in the mitochondrial intermembrane space of rat liver.

収録刊行物

キーワード

詳細情報 詳細情報について

問題の指摘

ページトップへ