Description
In enzymology, a protocatechuate 3,4-dioxygenase (EC 1.13.11.3) is an enzyme that catalyzes the chemical reaction: 3,4-dihydroxybenzoate + O2 ↔ 3-carboxy-cis,cis-muconate. Thus, the two substrates of this enzyme are 3,4-dihydroxybenzoate (protocatechuic acid) and O2, whereas its product is 3-carboxy-cis,cis-muconate. This enzyme belongs to the family of oxidoreductases, specifically those acting on single donors with O2 as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases). This enzyme participates in benzoate degradation via hydroxylation and 2,4-dichlorobenzoate degradation. It employs one cofactor, iron.
Abbr
Protocatechuate 3, 4-dioxygenase (Pseudomonas sp.)
Applications
This enzyme is useful for enzymatic determination of choline esterase when coupled with p-hydroxybenzoate hydroxylase.
Appearance
Light brown amorphous powder, lyophilized
Enzyme Commission Number
EC 1.13.11.3
Activity
GradeⅢ 3.0U/mg-solid or more (containing approx. 40% of stabilizers)
Contaminants
NADPH oxidase < 1.0×10⁻¹%
Molecular Weight
approx. 700 kDa
pH Stability
pH 7.0-9.0 (25°C, 72hr)
Michaelis Constant
1.85×10⁻⁵M (Protocatechuate)
Structure
Protein with nonheme iron
Optimum temperature
60-65°C
Thermal stability
below 50°C (pH 6.0, 1hr)
Stability
Store at -20°C (A decrease in activity of ca. 20% may occur within one year)
Inhibitors
Ag⁺, Hg⁺⁺, PCMB
Synonyms
EC 1.13.11.3; Protocatechuate 3,4-dioxygenase; protocatechuate: oxygen 3,4-oxidoreductase (decyclizing); protocatechuate oxygenase; protocatechuic acid oxidase; protocatechuic 3,4-dioxygenase; protocatechuic 3,4-oxygenase