Nitrate reductase
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Nitrate_reductase".

Nitrate reductase enzymes are a group of enzymes that reduce nitrate to nitrite.

• Nitrate reductase (1)- is a large and complex enzyme with multiple subunits and a mass of ~800 kDa. It contains bound FAD, Mo, and cytochrome 557, and has ferredoxin Fe₄S₄ center. It is NADH/NADPH-dependent according to organism. Mo is bound to a cofactor containing a pteridine ring to form molybdopterin.

• Nitrite reductase (2, 3, 4) catalyzes the last three steps in the reduction of nitrate to NH3. It contains one ferredoxin Fe₂S₂ center and one molecule of siroheme (partially-reduced Fe porphyrin) and the electron donor for each step is ferredoxin.

Bacteria can be differentiated based on whether they have nitrate reductases. (See Nitrate reductase test.)

External links

• UMich Orientation of Proteins in Membranes protein/pdbid-1q16
• MeSH Nitrate+reductases

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