Limonene-6-Hydroxylase (L6H)
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Contents
What we know
This enzyme is also known as (S)-limonene 6-monooxygenase, (-)-limonene 6-hydroxylase, (-)-limonene 6-monooxygenase, (-)-limonene,NADPH:oxygen oxidoreductase (6-hydroxylating)
Reaction catalysed
Metabolite and Enzyme Background Information
Long metabolite and enzyme names are abbreviated in the model for clarity and standard identification purposes.
Metabolite | Abbreviation | Chemical Formula | Molar mass (g/mol) | ChEBI | ChEMBL | PubChem | MetaCyc |
---|---|---|---|---|---|---|---|
(-)-4S-limonene | Limonene | C10H16 | 136.24 | 15384 | 449062 | 22311 or 439250 | |
(-)-trans-carveol | carveol | Chemical Formula | Molar mass (g/mol) | ChEBI | ChEMBL | PubChem | MetaCyc |
NADPH | NADPH | Chemical Formula | Molar mass (g/mol) | ChEBI | ChEMBL | PubChem | MetaCyc |
NADP | NADP | Chemical Formula | Molar mass (g/mol) | ChEBI | ChEMBL | PubChem | MetaCyc |
Limonene-6-hydroxylase | L6H | Chemical Formula | Molar mass (g/mol) | ChEBI | ChEMBL | PubChem | LIMONENE-6-MONOOXYGENASE-RXN |
Metabolite | Abbreviation | Chemical Formula | Molar mass (g/mol) | ChEBI | ChEMBL | PubChem | MetaCyc |
Equation Rate
This reaction is modelled using the reversible Michaelis-Menten equation, with two substrates; Limonene and NADPH, and two products; Carveol and NADP.
Parameter | Description | Reference |
---|---|---|
VLimSynth | Reaction rate for Limonene Synthase | ref |
Vmaxforward | Maximum reaction rate towards the production of limonene | ref |
KmGPP | Michaelis-Menten constant for GPP | ref |
KmLimonene | Michaelis-Menten constant for Limonene | ref |
KmPP | Michaelis-Menten constant for PP | ref |
Keq | Equilibrium constant | ref |
[GPP] | GPP concentration | ref |
[Limonene] | Limonene concentration | ref |
[PP] | PP concentration | ref |
Strategies for estimating the kinetic parameter values
Calculating the Equilibrium Constant
The equilibrium constant can be calculated using the Van't Hoff Isotherm equation:
where;
Keq | Equilibrium constant |
-?G° | Gibbs free energy change. For (INSERT ENZYME) it is (INSERT VALUE) kJmol-1 |
R | Gas constant with a value of 8.31 JK-1mol-1 |
T | Temperature which is always expressed in kelvin |
Standard Gibbs Free energy
No information yet could be found on the standard Gibbs free energy for L6H. However, Metacyc has the standard Gibbs free energy value for Limonene oxide, catalysing the formation of cis-carveol from limonene [RXN-9465] as -92.52051 kcal·mol-1 [1].
Published Kinetic Parameter Values
Km Values
Km (mM) | Unit | Substrate / Product | Directionality | Organism | References |
---|---|---|---|---|---|
Value | unit | substrate | directionality | organism | Ref |
Vmax values
Vmax | Unit | Directionality | Organism | References |
---|---|---|---|---|
Value | µmol/min/mg (unit) | directionality | Organism | References |
Kcat values
Kcat | Unit | Organism | Reference |
---|---|---|---|
value | s-1 | Organism | ref e.g. Alonso 1992 [2] |
Extracting Information from (INSERT SUBSTRATE/PRODUCT) Production Rates
Amount produced (mg/L) | Time (H) | Organism | Description | Reaction Flux (µM/s) |
---|---|---|---|---|
X | X | Y | Z | Z |
X | X | Y | Z | Z |
X | X | Y | Z | Z |
X | X | Y | Z | Z |
X | X | Y | Z | Z |
X | X | Y | Z | Z |
Published Kinetic Parameter Values
Km (mM) | Vmax | Kcat (s-1) | Kcat/Km | Organism | Description |
---|---|---|---|---|---|
0.00125 | - | - | Z | A -> B | |
0.0018 | - | - | - | Z | A -> B |
Y | Y | Y | Y | Z | A -> B |
Y | Y | Y | Y | Z | A -> B |
Y | Y | - | - | Z | A -> B |
Y | - | Y | - | Z | GPP -> B |
Y | - | Y | - | Z | GPP -> B |
x | - | y | - | Z. | A -> B |
Detailed descriptions of kinetic values used in this model
A more detailed description of the kinetic values listed above can be found here.
Simulations
References
- ↑ Latendresse, M. 2013. http://www.biocyc.org/PGDBConceptsGuide.shtml#gibbs. "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."
- ↑ Alonso et. al. 1992. "Purification of 4S-Limonene Synthase, a Monoterpene Cyclase from the Glandular Trichomes of Peppermint (Mentha x piperita) and Spearmint (Mentha spicata)", The Journal of Biological Chemistry, 267(11):7582-7587