Metabolic Modeling Tutorial
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Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
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MetaCyc Enzyme: 2-heptyl-3-hydroxy-4(1H)-quinolone synthase

Gene: pqsH Accession Number: G-12319 (MetaCyc)

Species: Pseudomonas aeruginosa PA14

Summary:
The subunit structure of this enzyme has not been reported.

PqsH catalyzes the terminal step in biosynthesis of the Pseudomonas quinolone signal molecule (PQS, 2-heptyl-3-hydroxy-4(1H)-quinolone). Experiments showed that under anaerobic conditions PQS is not produced and that oxygen is the sole limiting substrate during anaerobic growth. Thus, oxygen levels modulate the PQS-controlled factors in this organism [Schertzer10].

Recombinant enzyme was overexprressed in Escherichia coli both with and without a N-terminal fusion with the maltose binding protein (MBP). The MBP fusion did not appear to decrease activity and it improved solubility [Schertzer10].

The enzyme was found to be a member of the flavin-dependent monooxygenase family that utilizes NAD(P)H and oxygen to hydroxylate aromatic substrates (in [Schertzer10]).

Unification Links: Protein Model Portal:Q9I0Q0

Relationship Links: Entrez-gene:Ortholog:879540 , InterPro:IN-FAMILY:IPR002938 , InterPro:IN-FAMILY:IPR003042 , Pfam:IN-FAMILY:PF01494 , Prints:IN-FAMILY:PR00420 , UniProt:Ortholog:Q9I0Q0

Gene-Reaction Schematic: ?

Credits:
Created 19-Nov-2010 by Fulcher CA , SRI International


Enzymatic reaction of: 2-heptyl-3-hydroxy-4(1H)-quinolone synthase

Synonyms: 2-heptyl-3-hydroxy-quinolone synthase

EC Number: 1.14.13.182

2-heptyl-4(1H)-quinolone + NADH + oxygen + H+ <=> 2-heptyl-3-hydroxy-4(1H)-quinolone + NAD+ + H2O

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

The reaction is physiologically favored in the direction shown.

In Pathways: superpathway of quinolone and alkylquinolone biosynthesis , 2-heptyl-3-hydroxy-4(1H)-quinolone biosynthesis

Summary:
This reaction was demonstrated in vitro. Highest activity was found with substrates containing alkyl chain lengths of 7 and 9 carbons. The product was identified by TLC, absorbance and fluorescence spectra, and positive electrospray ionization mass spectrometry [Schertzer10].

Kinetic characterization was done with the MBP fusion protein. The enzyme could also use NADPH although the catalytic efficiency was approximately 20-fold lower than for NADH [Schertzer10].

Kinetic Parameters:

Substrate
Km (μM)
Citations
2-heptyl-4(1H)-quinolone
0.11
[Schertzer10]
oxygen
0.52
[Schertzer10]
NADH
32.0
[Schertzer10]


References

Schertzer10: Schertzer JW, Brown SA, Whiteley M (2010). "Oxygen levels rapidly modulate Pseudomonas aeruginosa social behaviours via substrate limitation of PqsH." Mol Microbiol 77(6);1527-38. PMID: 20662781


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 18.5 on Fri Nov 28, 2014, biocyc14.