Oxidoreductase dioxygenase

Schach S, B Tshisuaka, S Fetzner, F Lingens F (1995) Quinoline 2-oxidoreductase and 2-oxo-l,2-dihydro-quinoline 5,6-dioxygenase from Comamonas testosteroni 63. The first two enzymes in quinoline and 3-methylquinoline degradation. EurJ Biochem 232 536-544. 

The enzymes from Comamonas testosteroni for hydroxylation of quinoline to quinol-2-one (quinoline 2-oxidoreductase) and the dioxygenase responsible for the introduction of oxygen into the benzenoid ring (2-oxo-l,2-dihydroquinoline 5,6-dioxygenase) have been described (Schach et al. 1995). 

The first step in any of the degradation pathways is the formation of 2-quinolinone/2-hydroxyquinoline/2-oxo-l, 2-dihydroquinoline and quinoline2-oxidoreductase has been shown to be responsible for this initial metabolic reaction [318], When the oxidation is carried out by a dioxygenase, it resulted in the formation of ds-hydrodiol derivatives and when oxidation is carried out by a monooxygenase monohydroxilated derivatives are formed, via the arene oxide intermediates [323],... 

A broad spectrum of chemical reactions can be catalyzed by enzymes Hydrolysis, esterification, isomerization, addition and elimination, alkylation and dealkylation, halogenation and dehalogenation, and oxidation and reduction. The last reactions are catalyzed by redox enzymes, which are classified as oxidoreductases and divided into four categories according to the oxidant they utilize and the reactions they catalyze 1) dehydrogenases (reductases), 2) oxidases, 3) oxygenases (mono- and dioxygenases), and 4) peroxidases. The latter enzymes have received extensive attention in the last years as bio catalysts for synthetic applications. Peroxidases catalyze the oxidation of aromatic compounds, oxidation of heteroatom compounds, epoxidation, and the enantio-selective reduction of racemic hydroperoxides. In this article, a short overview... 

Other non-heme enzymes that use dioxygen are 4-methoxy-benzoate O-demethylase, extradiol catechol dioxygenases, the oxidoreductase isopenicillin N synthase, and a-keto acid-dependent enzymes (28). Moreover, the BH4-dependent glyceryl-ether monooxygenase (GEM) also appears to be dependent on nonheme iron for catalysis (see also Section I.E). 

Oxidoreductases NADorNADP Alcoholdehydrogenases Aldehyde dehydrogenases 2-enoate reductase Amino acid dehydrogenase Aromatic dioxygenase Methane monooxygenase... 

Fig. 20.3 Pathway of methionine metabolism. The numbers represent the following enzymes or sequences (1) methionine adenosyltransferase (2) S-adenosylmethionine-dependent transmethylation reactions (3) glycine methyltransferase (4) S-adenosylhomocysteine hydrolase (5) betaine-homocysteine methyltransferase (6) 5-methyltetrahydrofolate homocysteine methyltransferase (7) serine hydroxymethyltransferase (8) 5,10-methylenetetrahydrofolate reductase (9) S-adenosylmethionine decarboxylase (10) spermidine and spermine synthases (11) methylthio-adenosine phosphorylase (12) conversion of methylthioribose to methionine (13) cystathionine P-synthase (14) cystathionine y-lyase (15) cysteine dioxygenase (16) cysteine suplhinate decarboxylase (17) hypotaurine NAD oxidoreductase (18) cysteine sulphintite a-oxoglutarate aminotransferase (19) sulfine oxidase. MeCbl = methylcobalamin PLP = pyridoxal phosphate...

Protocatechuate intradiol dioxygenase (E.C. 1.13.11.3 - Protocate-chuate oxygen 3,4-oxidoreductase (decyclizing)... 

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