Protocatechuate extradiol dioxygenase

Protocatechuate extradiol dioxygenase (E.C. 1.13.11.8 - Protocate-chuate oxygen 4,5-oxidoreductase (decyclizing)... 

The extradiol dioxygenases are more common than the intradiol enzymes, and are more diverse in their reactions.1379 Examples are catechol 2,3-dioxygenase (from Pseudomonas arvilla and Ps. putida) and protocatechuate 4,5-dioxygenase from Ps. testosterone These are colourless and... 

Co-factor studies have been performed for all the enzymes listed, except for dihydroxy benzoate extradiol dioxygenase. Tests for dependence on ferrous ions and reducing agents and of inhibition by ferrous chelators and oxidizing agents indicate the presence of iron in the ferrous state in the active forms of metapyrocatechase 116), protocatechuate 83,117), dihydroxykynurenate (2), homoprotocatechuate 118), carboxy-... 

Wolgel SA, JE Dege, PE Perkins-Olson, CH Juarez-Garcia, RL Crawford, E Mtinck, JD Lipscomb (1993) Purification and characterization of protocatechuate 2,3-dioxygenase from Bacillus macerans a new extradiol catecholic dioxygenase. J Bacterial 175 4414-4426. 

This enzyme is colorless and contains the ferrous form of iron as the sole cofactor53,54 3,4-Dihydroxyphenylacetate 2,3-dioxygenase catalyzes the reaction shown in Eq. (14) and is an example of the proximal extradiol cleavage89-91. Protocatechuate 4,5-dioxygenase catalyzes the reaction shown in Eq.(15) and is an example of the distal extradiol cleavage92-94. ... 

For example, the enzyme pyrocatechase effects intradiol cleavage of catechol to muconic acid [72,73,74], whereas protocatechuate 3,4-dioxygenase promotes that of protocatechuic acid (R = COOH in 37) [75,76]. Metapyrocatechase is a catalyst for proximal extradiol cleavage of catechol to a-hydroxymuconic acid e-semialdehyde (38) [77] ... 

Protocatechuate 4,5-dioxygenase cleaves protocatechuic acid at the distal extradiol site [78] ... 

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