Gentisate pathway

When 1,4-dihydroxy compounds are produced by monooxygenation, these are degraded by the gentisate pathway (Figure 3.13) mediated by gentisate dioxygenase (Wergath et al. 1998). 

Gao X, CL Tan, CC Yeo, CL P (2005) Molecular and biochemical characterization of the x/ D-encoded 3-hydroxybenzoate 6 hydroxylase involved in the degradation of 2,5-xylenol via the gentisate pathway in Pseudomonas alcaligenes NCIMB 9S61. J Bacterial 187 7696-7702. 

Hydroxylation to 1,4-dihydroxy compounds may also activate the ring to oxidative fission. This is illustrated by the following examples of the gentisate pathway ... 

The gentisate pathway may plausibly be involved in the degradation of benzoate by a denitrifying strain of Pseudomonas sp. in which the initial reaction is the formation of 3-hydroxybenzoate (Altenschmidt et al. 1993). 

Goetz FE, L Harmuth (1992) Gentisate pathway in Salmonella typhimurium metabolism of m-hydroxybenzo-ate and gentisate. FEMS Microbiol Lett 91 45-50. 

Jones DCN, RA Cooper (1990) Catabolism of 3-hydroxybenzoate by the gentisate pathway in Klebsiella pneumoniae M5al. Arch Microbiol 154 489-495. 

Tham, J.M.L. and C.L. Poh. 1993. Insertional mutagenesis, cloning and expession of gentisate pathway genes from Pseudomonas alcaligenes NGB 9867. J. Appl. Bacteriol. 75 159-163. 

In some strains of pseudomonads, the degradation of the intermediate catechol produced by the activity of salicylate hydroxylase may proceed by the alternative intradiol cleavage pathway (Barnsley 1976). Reference has been made to the alternative gentisate pathway for the degradation of the intermediate salicylate (Grund et al. 1992). 

Poh, C.L. and R.C. Bayly. 1980. Evidence for isofunctional enzymes used in meta-cresol and 2,4-xylenol degradation via the gentisate pathway in Pseudomonas alcaligenes. J. Bacteriol. 143 59-69. 

Shen, X.H., Jiang, C.Y., Huang, Y, Liu, Z.P., and Liu, S.J. (2005) Functional identification of novel genes involved in the glutathione-independent gentisate pathway in Corynebacterium glutamicum. Appl Environ. Microbiol, 71 (7), 3442-3452. 

This comprises a heterogeneons gronp of enzymes that is used for the degradation of snbstrates including gentisate, salicylate, and l-hydroxynaphthalene-2-carboxylate by pathways that do not involve catechols ... 

Finally, there is a pathway, which is observed in Alcaligenes species where isatin and gentisate were the intermediates [345], The details of this complete pathway on Alcaligenes strains has not been reported, but the following reaction sequence was proposed [310] ... 

Figure 1. Catabolic pathways for degradation of naphthalene by bacteria. I, naphthalene II, cis-l,2-dihydro-l,2-dihydroxynaphthalene (naphthalene dihydrodiol) III, l,2-dihydrox3maphthalene IV, 2-hydroxy-chromene-2-carboxylate V, mns-o-hydroxybenzyIidene pyruvate VI, salicylaldehyde Vn, salicylate VIII catechol IX, c 5,ci8-muconate semialdehyde X, cis,ci8-muconate XI, gentisate XII, maleylpyruvate.

---