In
enzymology
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. A ...
, a phospholipid-hydroperoxide glutathione peroxidase () is an
enzyme that
catalyzes
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
the
chemical reaction
:2 glutathione + a lipid hydroperoxide
glutathione disulfide + lipid + 2 H
2O
Thus, the two
substrates of this enzyme are
glutathione and
lipid hydroperoxide, whereas its 3
products are
glutathione disulfide
Glutathione disulfide (GSSG) is a disulfide derived from two glutathione molecules.
In living cells, glutathione disulfide is reduced into two molecules of glutathione with reducing equivalents from the coenzyme NADPH. This reaction is catalyzed ...
,
lipid, and
H2O.
This enzyme belongs to the family of
oxidoreductases, to be specific those acting on a peroxide as acceptor (peroxidases). The
systematic name of this enzyme class is glutathione:lipid-hydroperoxide oxidoreductase. Other names in common use include peroxidation-inhibiting protein, PHGPX, peroxidation-inhibiting protein: peroxidase, glutathione, (phospholipid hydroperoxide-reducing), phospholipid hydroperoxide glutathione peroxidase, hydroperoxide glutathione peroxidase, or glutathione peroxidase 4 (
GPX4
Glutathione peroxidase 4, also known as GPX4, is an enzyme that in humans is encoded by the ''GPX4'' gene. GPX4 is a phospholipid hydroperoxidase that protects cells against membrane lipid peroxidation.
Function
The antioxidant enzyme gluta ...
). This enzyme participates in
glutathione metabolism
Glutathione (GSH, ) is an antioxidant in plants, animals, fungi, and some bacteria and archaea. Glutathione is capable of preventing damage to important cellular components caused by sources such as reactive oxygen species, free radicals, pe ...
.
Structural studies
As of late 2007, two
structures have been solved for this class of enzymes, with
PDB accession codes and .
References
*
EC 1.11.1
Enzymes of known structure
{{1.11-enzyme-stub