NAD (P) H dehydrogenase
| NAD (P) H dehydrogenase | ||
|---|---|---|
|
||
| NAD (P) H dehydrogenase tetramer, Brucella abortus according to PDB 5F4B | ||
| Identifier | ||
| External IDs |
|
|
| Enzyme classification | ||
| EC, category | 1.6.5.2 | |
The NAD (P) H-dehydrogenase is in plants occurring enzyme of the respiratory chain.
properties
The NAD (P) H dehydrogenase catalyzes the following reaction, including in steroid metabolism :
- NAD (P) H + H + + quinone NAD (P) + + hydroquinone
The 4 substrates of NAD (P) H dehydrogenase are NADH , NADPH , H + , and quinone , the 3 products are NAD + , NADP + and hydroquinone . It can be used as an alternative to NADH dehydrogenase (complex I). As a cofactor is FAD used. NAD (P) H dehydrogenase is one of the oxidoreductases , including NAD (P) H: quinone oxidoreductases . Other names of NAD (P) H dehydrogenase include Menadionreduktase , Phyllochinonreduktase , quinone reductase , DT-diaphorase , azoreductase , flavoprotein NAD (P) H quinone reductase , Menadionoxidoreduktase , NAD (P) H-Menadionreduktase , NAD (P) H Quinone dehydrogenase , NAD (P) H-quinone oxidoreductase , NAD (P) H: (quinone-acceptor) oxidoreductase , naphthoquinone reductase , p-benzoquinone reductase , viologen accepting pyridine nucleotide oxidoreductase , vitamin K reductase , diaphorase , NQO1 and QR1 .
function
Similar to complex I of the respiratory chain, NAD (P) H dehydrogenase oxidizes NADH + H + to NAD + . In contrast to this, however, it can also oxidize NADPH and does not pump any protons into the intermembrane space during the redox reaction . The enzyme, if present, is anchored peripherally on both sides of the inner mitochondrial membrane and transfers the electrons from the reduction partner (NAD (P) H) to ubiquinone (Q), which is then reduced to ubiquinol (QH 2 ).
Inhibitors
Dicumarol inhibits the reaction. In contrast to complex I, the NAD (P) H dehydrogenase is Rotenone -insensitive, i.e. Rotenone does not inhibit the NAD (P) H dehydrogenase. This is important because some higher plants (e.g. Barbasco ) produce Rotenone as a secondary substance.
literature
- Taiz, Zeiger: Physiology of Plants ; Spectrum, Berlin, 2000. ISBN 978-3827405371 .