2-Hydroxymuconic acid semialdehyde

Apparently, the presence of the chloro substituent blocks the next reaction, which normally operates on 2-hydroxymuconic acid semialdehyde to produce 2-oxo-pent-4-enoic acid ... 

If a meta-cleavage pathway is the only one available to a particular microorganism, then the 5-chloro-2-hydroxymuconic acid semialdehyde (Eq.17-8) will accumulate unless another initial biotransformation is performed on it. 

Hydroxymorpholine. see Morpholine a-Hydroxymuconic acid, see PCB-1221 a-Hydroxymuconic semialdehyde, see Benzene... 

Dioxygenases catalyze the incorporation of both atoms of molecular oxygen into the substrate. Microbial pyrocatechol dioxygenases contain non-heme iron as the sole cofactor and catalyze the oxidative cleavage of pyrocatechol to as,cis-muconic acid (intradiol equation 19) or to a-hydroxymuconic s-semialdehyde (extradiol equation 20).63"65 On... 

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] ... 

Figure 2. Intermediates in the aerobic bacterial metabolism of benzene. (I) c/s-benzene dihydrodiol, (II) catechol, (III) 2-hydroxymuconic semialdehyde, (IV) cis, cis- muconic acid.

Figure 2. Possible routes of a-hydroxymuconic semialdehyde formation from 2,3-dihydroxybenzoic acid...

Differently, a Moraxdla strain degraded PNP by replacing the nitrogroup with a hydroxyl group and accumulating traces of hydroquinone in the medium. Hydroquinone was then converted into P-ketoadipic acid via Y hydroxymuconic semialdehyde [65]. 

Carboxymethyl-muconic acid 5-(y-Carboxy-y-oxo)-propenyl-4,6-dihydroxy-picolinic acid a-Hydroxymuconic semialdehyde... 

The nonenzymic reactions of the primary oxidation product in acid also support the proposed structure (Mehler, 1958). In acid solutions the amino group may be hydrolyzed to form the enol of a /3-keto acid, which may be expected to decarboxylate easily. The acid degradation product appears to be identical with a compound obtained by enzymic oxidation of catechol (see page 98). This compound has recently been isolated by Trippet et al. (1960) and characterized as a-hydroxymuconic semialdehyde. 

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