The β-subunit of pea stem mitochondrial ATP synthase exhibits PPiase activity

Marco Zancani, Valentino Casolo, Carlo Peresson, Giorgio Federici, Andrea Urbani, Francesco Macrì, Angelo Vianello

Research output: Contribution to journalArticlepeer-review


A soluble protein with a molecular mass of 55 kDa has been purified from etiolated pea stem mitochondria. The protein exhibits a Mg2+-requiring PPiase activity, with an optimum at pH 9.0, which is not stimulated by monovalent cations, but inhibited by F-, Ca2+, aminomethylenediphosphate and imidodiphosphate. The protein does not cross-react with polyclonal antibodies raised against vacuolar, mitochondrial or soluble PPiases, respectively. Conversely, it cross-reacts with an antibody for the α/β-subunit of the ATP synthase from beef heart mitochondria. The purified protein has been analyzed by MALDI-TOF mass spectrometry and the results, covering the 30% of assigned sequence, indicate that it corresponds to the β-subunit of the ATP synthase of pea mitochondria. It is suggested that this enzymatic protein may perform a dual function as soluble PPiase or as subunit of the more complex ATP synthase.

Original languageEnglish
Pages (from-to)111-118
Number of pages8
Issue number2
Publication statusPublished - Oct 2003


  • β-Subunit
  • ATP synthase
  • Mitochondria
  • Pisum sativum
  • PPiase

ASJC Scopus subject areas

  • Biophysics


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