View source for Biology:Protocatechuate 3,4-dioxygenase

{{infobox enzyme
| Name       = protocatechuate 3,4-dioxygenase
| EC_number  = 1.13.11.3
| CAS_number = 9029-47-4
| GO_code    = 0018578
| image      = 3pca.jpg
| width      = 270
| caption    = Protocatechuate 3,4-dioxygenase hetero24mer, ''[[Biology:Pseudomonas putida|Pseudomonas putida]]''
}}
In [[Biology:Enzymology|enzymology]], a '''protocatechuate 3,4-dioxygenase''' ({{EC number|1.13.11.3}}) is an [[Biology:Enzyme|enzyme]] that [[Chemistry:Catalysis|catalyzes]] the [[Chemistry:Chemical reaction|chemical reaction]]

:[[Chemistry:Protocatechuic acid|3,4-dihydroxybenzoate]] + O<sub>2</sub> <math>\rightleftharpoons</math> 3-carboxy-cis,cis-muconate

Thus, the two [[Biology:Substrate (biochemistry)|substrates]] of this enzyme are 3,4-dihydroxybenzoate ([[Chemistry:Protocatechuic acid|protocatechuic acid]]) and [[Chemistry:Oxygen|O<sub>2</sub>]], whereas its [[Chemistry:Product|product]] is 3-carboxy-cis,cis-muconate.

This enzyme belongs to the family of [[Biology:Oxidoreductase|oxidoreductase]]s, specifically those acting on single donors with O<sub>2</sub> as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases).   The [[Biology:List of enzymes|systematic name]] 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 [[Chemistry:Benzoate degradation via hydroxylation|benzoate degradation via hydroxylation]] and 2,4-dichlorobenzoate degradation.  It employs one [[Biology:Cofactor (biochemistry)|cofactor]], [[Chemistry:Iron|iron]].

This enzyme has been found effective at improving organic fluorophore-stability in single-molecule experiments.<ref>{{cite journal | vauthors = Aitken CE, Marshall RA, Puglisi JD | year = 2008 | title = An Oxygen Scavenging System for Improvement of Dye Stability in Single-Molecule Fluorescence Experiments | journal = Biophys. J.  | volume = 94 | pages = 1826&ndash;1835 | doi = 10.1529/biophysj.107.117689 | pmid = 17921203 | issue = 5 | pmc = 2242739 | bibcode = 2008BpJ....94.1826A }}</ref> Commercial preps of the enzyme isolated from ''[[Biology:Pseudomonas|Pseudomonas]]'' [[Biology:Species|spp.]] generally require further purification to remove strong contaminating nuclease activity.

== Structural studies ==

As of late 2007, 37 [[Biology:Tertiary structure|structures]] have been solved for this class of enzymes, with [[Biology:Protein Data Bank|PDB]] accession codes {{PDB link|1EO2}}, {{PDB link|1EO9}}, {{PDB link|1EOA}}, {{PDB link|1EOB}}, {{PDB link|1EOC}}, {{PDB link|1YKK}}, {{PDB link|1YKL}}, {{PDB link|1YKM}}, {{PDB link|1YKN}}, {{PDB link|1YKO}}, {{PDB link|1YKP}}, {{PDB link|2BUM}}, {{PDB link|2BUQ}}, {{PDB link|2BUR}}, {{PDB link|2BUT}}, {{PDB link|2BUU}}, {{PDB link|2BUV}}, {{PDB link|2BUW}}, {{PDB link|2BUX}}, {{PDB link|2BUY}}, {{PDB link|2BUZ}}, {{PDB link|2BV0}}, {{PDB link|2PCD}}, {{PDB link|3PCA}}, {{PDB link|3PCB}}, {{PDB link|3PCC}}, {{PDB link|3PCD}}, {{PDB link|3PCE}}, {{PDB link|3PCF}}, {{PDB link|3PCG}}, {{PDB link|3PCH}}, {{PDB link|3PCI}}, {{PDB link|3PCJ}}, {{PDB link|3PCK}}, {{PDB link|3PCL}}, {{PDB link|3PCM}}, and {{PDB link|3PCN}}.

== See also ==
* [[Chemistry:Protocatechuic acid|Protocatechuic acid]]

== References ==
{{reflist|1}}
* {{cite journal | vauthors = Fujisawa H, Hayaishi O | year = 1968 | title = Protocatechuate 3,4-dioxygenase. I. Crystallization and characterization | journal = J. Biol. Chem.  | volume = 243 | pages = 2673&ndash;81  | pmid = 4967959 | issue = 10 }}
* {{cite journal | vauthors = GROSS SR, GAFFORD RD, TATUM EL | year = 1956 | title = The metabolism of protocatechuic acid by Neurospora | journal = J. Biol. Chem.  | volume = 219 | pages = 781&ndash;96  | pmid = 13319299 | issue = 2 }}
* {{cite journal | vauthors = Stanier RY, Ingraham JL | year = 1954 | title = Protocatechuic acid oxidase | journal = J. Biol. Chem.  | volume = 210 | pages = 799&ndash;820 | pmid=13211618 | issue=2}}

{{Monooxygenases}}
{{Enzymes}}

[[Category:EC 1.13.11]]
[[Category:Iron enzymes]]
[[Category:Enzymes of known structure]]



{{Sourceattribution|Protocatechuate 3,4-dioxygenase}}