Tyrosine is one of the 20 common amino acids found in all biological systems. It is catabolized as part of normal intermediary metabolism and in the breakdown of external proteins by soil microorganisms. Although it is not a xenobiotic compound, some of the intermediates of this pathway are also found in pathways for the catabolism of industrial and natural product aromatic ring compounds. One or more of these pathways are often found in Gram-positive and Gram-negative soil bacteria. In addition, Pseudomonas sp. strain CBS3 is able to convert 4-chlorophenylacetate to 3,4-dihydroxyphenylacetate. The latter merges into the pathway.
This is a text-format tyrosine degradation pathway map. Organisms which can initiate the pathway are 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 (17k) format.
L-Tyrosine
|
|
from the | L-tyrosine aminotransferase
DDT Pathway |
| |
| |
| v
| 4-Hydroxyphenylpyruvate
| Arthrobacter sp. / \ Pseudomonas sp.
| / \ strain P.J. 874
| / \
| 4-hydroxyphenylpyruvate / \ 4-hydroxyphenylpyruvate
| oxidase / \ dioxygenase
V / \
4-Chlorophenylacetate / 4-hydroxyphenylacetate \
Pseudomonas sp. / 1-hydroxylase \ from the
strain CBS3 4-Hydroxyphenylacetate ---------------------> Homogentisate <---- Phenylacetate
| | | Pathway
| | |
| 4-chlorophenyl- | 4-hydroxyphenylacetate | homogentisate
| acetate | 3-hydroxylase | 1,2-dioxygenase
| 3,4-dioxygenase | |
| | |
| v v
+----------> 3,4-Dihydroxyphenylacetate 4-Maleylacetoacetate
^ | |
from the | | |
3-Nitrotyramine -------+ | 3,4-dihydroxyphenyl- | maleylacetoacetate
Pathway | acetate | isomerase
| 2,3-dioxygenase |
| |
v v
trans,cis-5-Carboxymethyl- Fumarylacetoacetate
2-hydroxymuconate |
semialdehyde |
| |
| trans,cis- |
| 5-carboxymethyl- | fumarylacetoacetase
| 2-hydroxymuconic |
| semialdehyde |
| dehydrogenase |
| |
v v
trans,cis-5-Carboxymethyl- Fumarate + Acetoacetate
2-hydroxymuconate | |
| | |
| 5-carboxymethyl- | |
| 2-hydroxymuconate | |
| isomerase | |
| | |
v v v
cis-5-Carboxymethyl-2-oxohex- Intermediary Intermediary
3-ene-1,6-dioate Metabolism Metabolism
| (KEGG) (KEGG)
|
| homoprotocatechuate
| isomerase / decarboxylase
|
|
v
cis-2-Oxohept-3-ene-
1,7-dioate
|
| cis-2-oxohept-3-ene-
| 1,7-dioate hydratase
|
|
From the v
Pyridoxine 2,4-Dihydroxy-hept-
Pathway trans-2-ene-1,7-dioate
| |
| | 2,4-dihydroxy-hept-
| | trans-2-ene-1,7-dioate aldolase
| |
| |
v |
Succinic semialdehyde < + > Pyruvate
| |
| succinic |
| semialdehyde |
| dehydrogenase |
| |
v v
Succinate Intermediary
| Metabolism
| (KEGG)
|
|
|
v
Intermediary
Metabolism
(KEGG)
Page Author(s): Michelle Wagner, Colin L. Sweeney, Zhifu Sun and Michael Turnbull
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