1-Naphthoic Acid Pathway Map

Substituted and non-substituted naphthoic acids are excreted by various bacteria, fungi, and algae as dextoxification/biotransformation products of methyl naphthalenes, phenanthrene and anthracene. In bacterial systems, naphthoic acids have been shown to accumulate in the spent medium when Pseudomonas putida CSV86 was grown in the presence of 1- and 2- methylnaphthalene (Mahajan et al. 1994).

Phale et al. (1995) reported the pathway for metabolism of 1-naphthoic acid by a soil bacterium, Pseudomonas maltophilia (now Stenotrophomonas maltophilia) CSV89. The degradation of 1-naphthoic acid is initiated by double hydroxylation of the aromatic ring adjacent to the one bearing the carboxyl group, resulting in the formation of 1,2-dihydroxy-8-carboxynaphthalene. The resultant diol was oxidized via 2-hydroxy-3-carboxy benzalpyruvate, 3-formyl salicylate, 2-hydroxyisophthalate, salicylate and catechol to TCA cycle intermediates, thus serving as the sole source of carbon and energy.

The following is a text-format 1-naphthoic acid pathway map. An organism which can initiate the pathway is given, but other organisms may also carry out later steps. Follow the links for more information on compounds or reactions. This map is also available in graphic (18k) format.

                                                              from the
                    1-Naphthoic acid <------------------------1-Methylnaphthalene 
            Stenotrophomonas maltophilia CSV89                Pathway
                            |
                            |
                            | 1-naphthoic acid dioxygenase
                            | 
                            | 
                            v                               
    cis-1,2-Dihydroxy-1,2-dihydro-8-carboxynaphthalene       
                            |
                            | cis-1,2-dihydroxy-1,2-
                            | dihydro-8-carboxynaphthalene
                            | dehydrogenase
                            | 
                            v  
           1,2-Dihydroxy-8-carboxynaphthalene
                            |
                            | 1,2-dihydroxy-8-
                            | carboxynaphthalene 
                            | dioxygenase
                            | 
                            v 
          2-Carboxy-2-hydroxy-8-carboxychromene
                            |
                            | 2-carboxy-2-hydroxy-
                            | 8-carboxychromene 
                            | isomerase 
                            | 
                            v 
            2-Hydroxy-3-carboxy-benzalpyruvate
                            |
                            | 2-hydroxy-3-
                            | carboxy-benzalpyruvate  
                            | hydratase-aldolase
                            | 
                            v 
            3-Formylsalicyclic acid + Pyruvate
                            |
                            |
                            | 3-formylsalicylate oxidase
                            | 
                            | 
                            v 
                2-Hydroxyisophthalic acid 
                            |
                            |
                            | 2-hydroxyisophthalate
                            | decarboxylase 
                            | 
                            v 
                       Salicylate          
                            |
                            |  
                            | 
                            | 
                            | 
                            v 
                          to the 
                   Naphthalene Pathway 
                          

Page Author(s): Bo Kyeng Hou

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