This pathway shows the aerobic degradation of 1-Methylnaphthalene by Pseudomonas putida CSV86. 1-Methylnaphthalene is a bicyclic aromatic hydrocarbon which is found in crude oil and other petroleum products and appears in the environment as a pollutant. The degradation of polycyclic aromatic hydrocarbons (PAHs) like 1-Methylnaphthalene is of great interest because many of these PAHs are known human carcinogens.
A soil isolate, Pseudomonas putida CSV86 is able to grow using 1-and 2-Methylnaphthalene as the sole sources of carbon and energy (Mahajan et al., 1994). The organism degrades 1-methylnaphthalene by two pathways: In the first, an aromatic ring hydroxylation pathway, the unsubstituted ring of methylnaphthalene is doubly hydroxylated yielding cis-1,2-dihydroxy-1,2-dihydro-8-methylnaphthalene, which is further oxidized to methyl salicylate and methyl catechol and enters into TCA cycle. In the second, a detoxification pathway, the methyl group is hydroxylated to form 1-hydroxymethylnaphthalene which is further oxidized to 1-naphthoic acid and excreted into the medium as a dead end product as organism P. putida CSV86 failed to grow on 1-naphthoic acid as a sole source of carbon and energy (Mahajan et al., 1994). Other organisms able to degrade 1-Methylnaphthalene include Marinobacter sp. NCE312, Neptunomonas naphthovorans, and the fungus Cunninghamella elegans.
Naphthalene dioxygenase, an enzyme in this pathway, is used in a biotechnological process to synthesize the blue jean dye indigo. This versatile enzyme has many other catalytic abilities, which are documented in a table of the Reactions of Naphthalene 1,2-dioxygenase.
The following is a text-format 1-Methylnaphthalene degradation pathway map. Organisms which can initiate the pathway are given, but other organisms may also carry out later steps. Follow the links to find out abut the compounds and reactions.
Graphical Map (30k) | Graphical Map (20k)
1-Methylnaphthalene 1-Methylnaphthalene
Pseudomonas putida CSV86
| |
| |
| naphthalene | 1-methylnaphthalene
| 1,2-dioxygenase | hydroxylase
| |
v v
cis-1,2-Dihydroxy 1-Hydroxymethylnaphthalene
1,2-dihydro |
8-methylnaphthalene |
| |
| 1,2-dihydroxy-1,2- | alcohol
| dihydro- | dehydrogenase
| naphthalene |
| dehydrogenase |
| |
v v
1,2-Dihydroxy 1-Naphthaldehyde
8-methylnaphthalene |
| |
| |
| 1,2-dihydroxy- | 1-naphthaldehyde
| 8-methylnaphthalene | dehydrogenase
| dioxygenase |
| |
v v
2-Hydroxy-8-methyl- 1-Naphthoic acid
chromene-2-carboxylate |
| |
| |
| 2-hydroxy-8-methyl- |
| chromene-2-carboxylate |
| isomerase |
| |
| |
v v
2-Hydroxy-3-methyl- to the
benzalpyruvate 1-Naphthoic Acid Pathway
|
|
| 2-hydroxy-3-methyl-
| benzalpyruvate
| hydratase-aldolase
|
v
3-Methylsalicylaldehyde + Pyruvate
|
|
| 3-methylsalicylaldehyde
| dehydrogenase
|
|
v
3-Methylsalicylate
|
|
| salicylate
| hydroxylase
|
|
v
3-Methylcatechol + Carbon dioxide
|
|
|
|
|
|
v
to the
Toluene Pathway
Page Author(s): Sivakumaran Raman
Contact Us© 2024, EAWAG. All rights reserved. http://eawag-bbd.ethz.ch/1mna/1mna_map.html