Transformation of AA to 15-HPETE
The genes ALOX15B and ALOX15 encodes the formation of two isoforms of 15-lioxygenase (15-LOX). The gene ALOX15B encodes the formation of 15-LOX-2, which converts AA exclusively into 15(S)-HPETE. Whereas the gene ALOX15 encodes the 15-LOX-1 protein, which converts AA into both 12(S)-HPETE and 15(S)-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
15-LOX Parameters
Kms
Value | Units | Species | Notes | Weight | Reference |
---|---|---|---|---|---|
3.70E-03 ± 3.00E-04 | Human | Expression Vector: Epithelium
Enzyme: 15-Lipoxygenase pH: 7.5 Temperature: 25 |
512 | [1] | |
5.00E-03 | Human | Expression Vector: Reticulocyte
Enzyme: 15-Lipoxygenase pH:7.5 Temperature: Unspecified |
512 | [2] | |
1.06E-02 | Human | Expression Vector: Keratinocyte
Enzyme: 15-Lipoxygenase pH: 6.7 - 7.3 Temperature: 37 |
2048 | [3] | |
1.17E-02 ± 9.00E-04 | Human | Expression Vector: Baculovirus Insect Cell
Enzyme: Wildtype 15-Lipoxygenase pH: 6.8 Temperature: 37 |
512 | [4] |
Mode (mM) | Confidence Interval | Location parameter (µ) | Scale parameter (σ) |
---|---|---|---|
1.02E-02 | 2.40E+00 | -4.42E+00 | 4.10E-01 |
Kmp
Mode (mM) | Location parameter (µ) | Scale parameter (σ) |
---|---|---|
1.02E-02 | -4.42E+00 | 4.11E-01 |
kcat
Value | Units | Species | Notes | Weight | Reference |
---|---|---|---|---|---|
595.8 ± 16.8 | Human | Expression Vector: Epithelium
Enzyme: 15-Lipoxygenase pH: 7.5 Temperature: 25 |
512 | [1] | |
37.2 ± 1.8 | per minute | Expression Vector:Human prostate epithelial
Enzyme:15-lipoxygenase-2 |
pH 7, Temperature: 22 | 512 | [5] |
45 ± 1.2 | pH 7.5, Temperature: 22 | ||||
44.4 ± 2.4 | pH 8, Temperature: 22 | ||||
34.2 ± 0.6 | 15°C, pH = 7.5 | ||||
45 ± 1.2 | 22°C, pH = 7.5 | ||||
62.4 ± 4.2 | 30°C, pH = 7.5 | ||||
82.8 ± 4.8 | 37°C, pH = 7.5 |
Mode (min-1) | Confidence Interval | Location parameter (µ) | Scale parameter (σ) |
---|---|---|---|
6.51E+01 | 4.62E+00 | 4.60E+00 | 6.50E-01 |
Enzyme concentration
To convert the enzyme concentration from ppm to mM, the following equation was used.
Value | Units | Species | Notes | Weight | Reference |
---|---|---|---|---|---|
4.09 | Human | Expression Vector: Lung
Enzyme: 15-LOX pH: 7.5 Temperature: 37 °C |
1024 | [6] | |
37.4 | Human | Expression Vector: Spleen
Enzyme: 15-LOX pH: 7.5 Temperature: 37 °C |
1024 | [7] | |
1.40 | Human | Expression Vector: Gut
Enzyme: 12-LOX pH: 7.5 Temperature: 37 °C |
1024 | [6] |
Mode (ppm) | Mode (mM) | Confidence Interval | Location parameter (µ) | Scale parameter (σ) |
---|---|---|---|---|
4.07 | 2.25E-05 | 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: 15-LOX Substrate: Arachidonate Product: 15-HPETE pH: 7.3 ionic strength: 0.25 |
64 | [8] |
Mode | Confidence Interval | Location parameter (µ) | Scale parameter (σ) |
---|---|---|---|
2.27E+51 | 1.00E+01 | 1.19E+02 | 8.90E-01 |
References
- ↑ 1.0 1.1 Jacquot C. "Isotope sensitive branching and kinetic isotope effects in the reaction of deuterated arachidonic acids with human 12- and 15-lipoxygenases. Biochemistry. 2008 Jul 8;47(27):7295-303. doi: 10.1021/bi800308q. Epub 2008 Jun 12.
- ↑ Jacquot C. "Synthesis of 11-Thialinoleic Acid and 14-Thialinoleic Acid, Inhibitors of Soybean and Human Lipoxygenases Org Biomol Chem. 2008 Nov 21; 6(22): 4242–4252.
- ↑ Burrall B. "Enzymatic properties of the 15-lipoxygenase of human cultured keratinocytes. J Invest Dermatol. 1988 Oct;91(4):294-7.
- ↑ Sloane D. L. "Conversion of human 15-lipoxygenase to an efficient 12-lipoxygenase: the side-chain geometry of amino acids 417 and 418 determine positional specificity. Protein Eng. 1995 Mar;8(3):275-82..
- ↑ Wecksler A. "Kinetic and Structural Investigations of the Allosteric Site in Human Epithelial 15-Lipoxygenase-2 Biochemistry, 2009, 48 (36), pp 8721–8730
- ↑ 6.0 6.1 M. Kim A draft map of the human proteome Nature, 2014 509, 575–581
- ↑ M. Wilhelm Mass-spectrometry-based draft of the human proteome Nature, 2014 509, 582–587
- ↑ 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