NAD(P)H-ubiquinone oxidoreductases in plant mitochondria

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.

NATURVETENSKAP Biologi Biokemi och molekylärbiologi hsv//swe
NATURAL SCIENCES Biological Sciences Biochemistry and Molecular Biology hsv//eng
(Plant) mitochondria
calcium
Complex I
electrostatic interactions
NAD(P)H dehydrogenase
NAD(P)H-ubiquinone oxidoreductase
rotenone

Rasmusson, Allan G.Lund University,Lunds universitet,Molekylär cellbiologi,Biologiska institutionen,Naturvetenskapliga fakulteten,Molecular Cell Biology,Department of Biology,Faculty of Science(Swepub:lu)fysb-ara (författare)
Fredlund, Kenneth M. (författare)
Molekylär cellbiologiBiologiska institutionen (creator_code:org_t)

Av författaren/redakt...: Møller, Ian M.; Rasmusson, Allan ...; Fredlund, Kennet ...

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