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. 2022 Oct 13;33(1):1–14. doi: 10.4014/jmb.2208.08048

Fig. 3. Catabolic pathways of TPA to aromatic chemicals: catechol, PCA, and other high value-added chemicals.

Fig. 3

The α-ketoadipate pathway (blue line) consists of genes, namely, PcaHG (protocatechuate 3,4-dioxygenase), PcaB (3-carboxy-cis, cis-muconate cycloisomerase), PcaC (γ-carboxy-muconolactone decarboxylase), and PcaD (β-ketoadipate enol-lactone). The targeted products include: CMA, β-carboxy-cis,cis-muconic acid, CML-γ-carboxymuconolactone, MCL, Muconolactone,KA,β-ketoadipic acid. The PCA 2,3-cleavage pathway (light green lines) consists of genes, namely, PraA, (PCA 2,3-dioxygenase), PraH, (5 CHMS decarboxylase), 5C-2HMS dehydrogenase, XyHI,4-oxalocrotonate isomerase, XyIJ,2- oxopent-4-enoate hydratase,XyIK, 4-hydroxy-2-oxovalerate aldolase, XyIQ, acetaaldehyde dehydrogenase. The targeted molecules are: CHMS, 5-Carboxy-2-hydroxymuconate-semialdehyde, ICA, isocinchomeronic acid, HMS, 2-Hydroxymuconate semialdehyde, PCL-picolinic acid, HPD/OEA, 2-Hydroxypenta-2,4-dienoic acid/2-oxopent-4-enoic acid, HOA, 4-Hydroxy- 2-oxovaleric acid. The other pathway (grey line) is encoded by LigAB,4,5-PDC,Lig C,CHMS dehydrogenase, Lig I, PDC hydrolase, LigJ, OMA hydratase, LigK, CHA(4-carboxy-4-hydroxy-2-oxoadipate) aldolase yields energy compounds. The targeted compounds include: HCMS, 4-Carboxy-2-hydroxymuconate-semialdehyde, DPA-dinicotinic acid, PDC, 2-pyrone- 4,6-dicarboxylic acid, CHA, 4-Carboxy-4-hydroxy-2-oxoadipic acid. Catechol is catabolized by CatA, Catechol 1,2- dioxygenase,CatB, Muconate cycloisomerase and Cat C, Muconolactone isomerase into MA, cis,cis-Muconic acid.