In
enzymology
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...
, a protocatechuate 3,4-dioxygenase () is an
enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...
that
catalyzes
Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...
the
chemical reaction
A chemical reaction is a process that leads to the chemistry, chemical transformation of one set of chemical substances to another. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an Gibbs free energy, ...
:
3,4-dihydroxybenzoate + O
2 3-carboxy-cis,cis-muconate
Thus, the two
substrates of this enzyme are 3,4-dihydroxybenzoate (
protocatechuic acid
Protocatechuic acid (PCA) is a dihydroxybenzoic acid, a type of phenolic acid. It is a major metabolite of antioxidant polyphenols found in green tea. It has mixed effects on normal and cancer cells in ''in vitro'' and ''in vivo'' studies. It is ...
) and
O2, whereas its
product is
3-carboxy-cis,cis-muconate.
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 ut ...
s, specifically those acting on single donors with O
2 as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases). 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 semitrivi ...
of this enzyme class is protocatechuate:oxygen 3,4-oxidoreductase (decyclizing). Other names in common use include protocatechuate oxygenase, protocatechuic acid oxidase, protocatechuic 3,4-dioxygenase, and protocatechuic 3,4-oxygenase. This enzyme participates in
benzoate degradation via hydroxylation Benzoate degradation via hydroxylation is an enzyme-catalyzed, bacterial chemical reaction. Benzoate is degraded aerobically and anaerobically. Aerobic degradation forms catechol. Anaerobic degradation forms cyclohex-1,5-diene-1-carbonylCoA. A hybr ...
and
2,4-dichlorobenzoate degradation. It employs one
cofactor,
iron
Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...
.
This enzyme has been found effective at improving organic fluorophore-stability in single-molecule experiments.
Commercial preps of the enzyme isolated from ''
Pseudomonas
''Pseudomonas'' is a genus of Gram-negative bacteria belonging to the family Pseudomonadaceae in the class Gammaproteobacteria. The 348 members of the genus demonstrate a great deal of metabolic diversity and consequently are able to colonize a ...
''
spp. generally require further purification to remove strong contaminating nuclease activity.
Structural studies
As of late 2007, 37
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 .
See also
*
Protocatechuic acid
Protocatechuic acid (PCA) is a dihydroxybenzoic acid, a type of phenolic acid. It is a major metabolite of antioxidant polyphenols found in green tea. It has mixed effects on normal and cancer cells in ''in vitro'' and ''in vivo'' studies. It is ...
References
*
*
*
EC 1.13.11
Iron enzymes
Enzymes of known structure
Natural phenols metabolism
{{1.13-enzyme-stub