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NAD(P)H-ubiquinone oxidoreductases in plant mitochondria

Author:
  • Ian M. Møller
  • Allan G. Rasmusson
  • Kenneth M. Fredlund
Publishing year: 1993-08
Language: English
Pages: 377-384
Publication/Series: Journal of Bioenergetics and Biomembranes
Volume: 25
Issue: 4
Document type: Journal article
Publisher: Kluwer

Abstract english

Plant (and fungal) mitochondria contain multiple NAD(P)H dehydrogenases in the inner membrane all of which are connected to the respiratory chain via ubiquinone. On the outer surface, facing the intermembrane space and the cytoplasm, NADH and NADPH are oxidized by what is probably a single low-molecular-weight, nonproton-pumping, unspecific rotenone-insensitive NAD(P)H dehydrogenase. Exogenous NADH oxidation is completely dependent on the presence of free Ca2+ with a K0.5 of about 1 μM. On the inner surface facing the matrix there are two dehydrogenases: (1) the proton-pumping rotenone-sensitive multisubunit Complex I with properties similar to those of Complex I in mammalian and fungal mitochondria. (2) a rotenone-insensitive NAD(P)H dehydrogenase with equal activity with NADH and NADPH and no proton-pumping activity. The NADPH-oxidizing activity of this enzyme is completely dependent on Ca2+ with a K0.5 of 3 μM. The enzyme consists of a single subunit of 26 kDa and has a native size of 76 kDa, which means that it may form a trimer.

Keywords

  • Biochemistry and Molecular Biology
  • (Plant) mitochondria
  • calcium
  • Complex I
  • electrostatic interactions
  • NAD(P)H dehydrogenase
  • NAD(P)H-ubiquinone oxidoreductase
  • rotenone

Other

Published
  • ISSN: 0145-479X
Allan Rasmusson
E-mail: allan [dot] rasmusson [at] biol [dot] lu [dot] se

Professor

Molecular Cell Biology

+46 46 222 93 81

B-A329A

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