Transformation of AA to 12-HPETE
The 12- LOX enzyme catalyses the addition of O2 at the C-12 position of AA, producing 12-HPETE. The formation of the unstable hydroperoxy fatty acids (HPETE) begins with the abstraction of a hydrogen radical at the allylic position between two double bonds. The structure undergoes a rearrangement reaction which results in the formation of a conjugated diene system. The insertion of molecular oxygen and a hydrogen leads to the formation of the final structure, a hydroperoxy fatty acid.
Contents
Reaction
Chemical equation
Rate equation
Enzyme Parameters
Kms
Value | Units | Species | Notes | Weight | Reference |
---|---|---|---|---|---|
7.20E-03 | Human | Expression Vector: Platelet
Enzyme: 12-Lipoxygenase pH: 7.4 Temperature: 37°C. |
2048 | [1] | |
8.00E-02 | Human | Expression Vector: Platelet
Enzyme: 12-Lipoxygenase pH: 7 Temperature: 24 |
512 | [2] | |
1.00E-02 | Human Platlet | Expression Vector: Baculovirus
Enzyme: 12-Lipoxygenase pH: 8 Temperature: 37 |
256 | [3] | |
7.90E-03 ± 8.00E-04 | Human | Expression Vector: Platelets
Enzyme:12-Lipoxygenase pH: 7.4 Temperature: 37 |
2048 | [4] |
Mode (mM) | Confidence Interval | Location parameter (σ) | Scale parameter (σ) |
---|---|---|---|
7.60E-03 | 4.34E+00 | -4.48E+00 | 6.30E-01 |
Kmp
This is a “Dependent parameter”, meaning that the log-normal distribution for this parameter was calculated using multivariate distributions (this is discussed in detail here). As a result, no confidence interval factor or literature values were cited for this parameter.
Mode (mM) | Location parameter (µ) | Scale parameter (σ) |
---|---|---|
7.30E-03 | -4.52E+00 | 6.28E-01 |
kcat
Value | Units | Species | Notes | Weight | Reference |
---|---|---|---|---|---|
336 ± 12 | per minute | Human | Expression Vector: Human reticulocyte
Enzyme: 15-lipoxygenase-1 pH: 7.5 Temperature: 25 |
256 | [5] |
504 | per minute | Wild Boar | Expression Vector: E. coli.
Enzyme: 12-Lipoxygenase pH: 7.4 Temperature: 37 |
1024 | [6] |
Mode (min-1) | Confidence Interval | Location parameter (µ) | Scale parameter (σ) |
---|---|---|---|
4.87E+02 | 1.20E+00 | 6.22E+00 | 1.80E-01 |
Enzyme concentration
To convert the enzyme concentration from ppm to mM, the following equation was used.
Value | Units | Species | Notes | Weight | Reference |
---|---|---|---|---|---|
19.8 | Human | Expression Vector: Spleen
Enzyme: 12-LOX pH: 7.5 Temperature: 37 °C |
1024 | [7] | |
1.60 | Human | Expression Vector: Liver
Enzyme: 12-LOX pH: 7.5 Temperature: 37 °C |
1024 | [8] | |
0.28 | Human | Expression Vector: Gut
Enzyme: 12-LOX pH: 7.5 Temperature: 37 °C |
1024 | [8] | |
0.11 | Human | Expression Vector: Pancreas
Enzyme: 12-LOX pH: 7.5 Temperature: 37 °C |
1024 | [8] |
Mode (ppm) | Mode (mM) | Confidence Interval | Location parameter (µ) | Scale parameter (σ) |
---|---|---|---|---|
4.98E-01 | 2.76E-06 | 7.23E+00 | 7.12E-01 | 1.19E+00 |
Keq
Gibbs Free Energy Change | Units | Species | Notes | Weight | Reference |
---|---|---|---|---|---|
(-69.979996) | kcal/mol | Not stated | Estimated
Enzyme: 12-LOX Substrate: Arachidonate Product: 12-HPETE pH: 7.3 ionic strength: 0.25 |
64 | [9] |
Mode | Confidence Interval | Location parameter (µ) | Scale parameter (σ) |
---|---|---|---|
2.27E+51 | 1.00E+01 | 1.19E+02 | 8.90E-01 |
References
- ↑ Lagarde M. "Subcellular localization and some properties of lipoxygenase activity in human blood platelets. Biochem J. 1984 Sep 1;222(2):495-500.
- ↑ Hada T. "Catalytic properties of human platelet 12-lipoxygenase as compared with the enzymes of other origins. Biochim Biophys Acta. 1991 Apr 24;1083(1):89-93.
- ↑ Chen X. S. "Purification and characterization of recombinant histidine-tagged human platelet 12-lipoxygenase expressed in a baculovirus/insect cell system. Eur J Biochem. 1993 Jun 15;214(3):845-52.
- ↑ Romano M. "Lipoxin synthase activity of human platelet 12-lipoxygenase. Biochem J. 1993 Nov 15;296 ( Pt 1):127-33.
- ↑ [www.ncbi.nlm.nih.gov/pubmed/19469483 Wecksler A. "Mechanistic Investigations of Human Reticulocyte 15- and Platelet 12-Lipoxygenases with Arachidonic Acid Biochemistry, 2009, 48 (26), pp 6259–6267]
- ↑ Richards K. "Leukocyte 12-Lipoxygenase: Expression, Purification, and Investigation of the Role of Methionine Residues in Turnover-Dependent Inactivation and 5,8,11,14-Eicosatetraynoic Acid Inhibition Biochemistry, 1997, 36 (22), pp 6692–6699
- ↑ M. Wilhelm Mass-spectrometry-based draft of the human proteome Nature, 2014 509, 582–587
- ↑ 8.0 8.1 8.2 M. Kim A draft map of the human proteome Nature, 2014 509, 575–581
- ↑ Caspi et al 2014, "The MetaCyc database of metabolic pathways and enzymes and the BioCyc collection of Pathway/Genome Databases," Nucleic Acids Research 42:D459-D471