In
enzymology, a ferredoxin—nitrite reductase () is an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...
that
catalyzes the
chemical reaction
A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the pos ...
:NH
3 + 2 H
2O + 6 oxidized
ferredoxin nitrite + 6 reduced ferredoxin + 7 H
+
The 3
substrates of this enzyme are
NH3,
H2O, and
oxidized ferredoxin, whereas its 3
products
Product may refer to:
Business
* Product (business), an item that serves as a solution to a specific consumer problem.
* Product (project management), a deliverable or set of deliverables that contribute to a business solution
Mathematics
* Produ ...
are
nitrite,
reduced ferredoxin, and
H+.
This enzyme belongs to the family of
oxidoreductase
In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule, the reductant, also called the electron donor, to another, the oxidant, also called the electron acceptor. This group of enzymes usually u ...
s, specifically those acting on other nitrogenous compounds as donors with an iron-sulfur protein as acceptor. The
systematic name A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection. Systematic names are usually part of a nomenclature.
A semisystematic name or semitrivial ...
of this enzyme class is ammonia:ferredoxin oxidoreductase. This enzyme participates in
nitrogen metabolism and
nitrogen assimilation Nitrogen assimilation is the formation of organic nitrogen compounds like amino acids from inorganic nitrogen compounds present in the environment. Organisms like plants, fungi and certain bacteria that can fix nitrogen gas (N2) depend on the abil ...
. It has 3
cofactors
Cofactor may also refer to:
* Cofactor (biochemistry), a substance that needs to be present in addition to an enzyme for a certain reaction to be catalysed
* A domain parameter in elliptic curve cryptography, defined as the ratio between the order ...
:
iron
Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundanc ...
,
Siroheme
Siroheme (or sirohaem) is a heme-like prosthetic group at the active sites of some enzymes to accomplish the six-electron reduction of sulfur and nitrogen. It is a cofactor at the active site of sulfite reductase, which plays a major role in ...
, and
Iron-sulfur.
This enzyme can use many different isoforms of ferredoxin. In photosynthesizing tissues, it uses ferredoxin that is reduced by
PSI
Psi, PSI or Ψ may refer to:
Alphabetic letters
* Psi (Greek) (Ψ, ψ), the 23rd letter of the Greek alphabet
* Psi (Cyrillic) (Ѱ, ѱ), letter of the early Cyrillic alphabet, adopted from Greek
Arts and entertainment
* "Psi" as an abbreviatio ...
and in the root it uses a form of ferredoxin (FdIII) that has a less negative midpoint potential and can be reduced easily by NADPH.
Structural studies
As of late 2007, 3
structures
A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as ...
have been solved for this class of enzymes, with
PDB accession codes , , and .
References
Literature
*
*
*
EC 1.7.7
Iron enzymes
Siroheme enzymes
Iron-sulfur enzymes
Enzymes of known structure
{{1.7-enzyme-stub