Difference between revisions of "Transformation of 15-HPETE to 15-HETE"

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[[Welcome to the In-Silico Model of Cutaneous Lipids Wiki | Return to overview]]
 
[[Welcome to the In-Silico Model of Cutaneous Lipids Wiki | Return to overview]]
  
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15-HPETE is reduced by phospholipid hydroperoxide glutathione peroxidase (PHGPx) to the corresponding alcohol, 15-HETE (Suth01). 15-HETE and 12-HETE have reciprocal activity during inflammation, for example 15-HETE reduces the infiltration of inflammatory cells, meanwhile 12-HETE acts as an activator for infiltrating immune cells (Dowd, Kobza Black et al. 1985, Serhan, Jain et al. 2003).
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Upon being generated, 15-HPETE can be reduced by an oxidoreductase enzyme, phospholipid hydroperoxide glutathione peroxidase (PHGPx), to form 15-HETE respectively.  
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== Reaction ==
 
== Reaction ==
  
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=== Enzyme concentration ===
 
=== Enzyme concentration ===
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To convert the enzyme concentration from ppm to mM, the following [[Common equations#Enzyme concentration (mM)|equation]] was used.
  
 
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|+  style="text-align: left;" | Description of the PHGPx concentration distribution
 
|+  style="text-align: left;" | Description of the PHGPx concentration distribution
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! Mode (mM) !! Confidence Interval !! Location parameter (µ) !! Scale parameter (σ)
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! Mode (ppm) !! Mode (mM) !! Confidence Interval !! Location parameter (µ) !! Scale parameter (σ)
 
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| 3.14E+02 || 1.38E+00 || 5.85E+00 || 3.09E-01
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| 3.14E+02 || 1.74E-03|| 1.38E+00 || 5.85E+00 || 3.09E-01
 
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Latest revision as of 08:21, 21 August 2019

Return to overview

Upon being generated, 15-HPETE can be reduced by an oxidoreductase enzyme, phospholipid hydroperoxide glutathione peroxidase (PHGPx), to form 15-HETE respectively.

Reaction

R18 HPETE15-HETE15.jpg

Chemical equation

15-HPETE \rightleftharpoons 15-HETE

Rate equation

R18.PNG

Parameters

Note that the literature values are the same as reaction 12.

Kms

Literature values
Value Units Species Notes Weight Reference
3.00E-01 mM Human Expression Vector: Bioimprited Enzyme - Selenosubtilisin

Enzyme: Glutathione Peroxidase pH: 7 Temperature: 37

512 [1]
11.1 ± 2.90E-01 mM Human Expression Vector: E Coli

Enzyme: Wild Type Glutathione Peroxidase Enzyme (Se-hGSTZ1-1) pH: 7 Temperature: 37

1024 [2]
4.00E-03 mM Rat Expression Vector: Rat Liver Cells

Enzyme: Glutathione Peroxidase pH: 7.4 Temperature: 37

768 [3]
Description of the PHGPx Kms distribution
Mode (mM) Confidence Interval Location parameter (µ) Scale parameter (σ)
3.19E-01 1.02E+03 2.54E+00 1.92E+00
The estimated probability distribution for PHGPx Kms. The value and weight of the literature values used to define the distribution are indicated by an orange dashed line. The x axis is plotted on a log-scale.

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.

Description of the PHGPx Kmp distribution
Mode (mM) Location parameter (µ) Scale parameter (σ)
3.15E-01 2.53E+00 1.92E+00
The estimated probability distribution for PHGPx Kmp. The value and weight of the literature values used to define the distribution are indicated by an orange dashed line. The x axis is plotted on a log-scale.

kcat

Literature values
Value Units Species Notes Weight Reference
1170 ± 50 min^{-1} Human Expression Vector: Bioimprited Enzyme - Selenosubtilisin

Enzyme: Glutathione Peroxidase pH: 7 Temperature: 37

512 [1]
24500 ± 150 min^{-1} Human Expression Vector: E Coli

Enzyme: Wild Type Glutathione Peroxidase Enzyme (Se-hGSTZ1-1) pH: 7 Temperature: 37

1024 [2]
Description of the PHGPx kcat distribution
Mode (min-1) Confidence Interval Locati1024on parameter (µ) Scale parameter (σ)
2.44E+04 4.20E+00 1.11E+01 9.75E-01
The estimated probability distribution for PHGPx kcat. The value and weight of the literature values used to define the distribution are indicated by an orange dashed line. The x axis is plotted on a log-scale.

Enzyme concentration

To convert the enzyme concentration from ppm to mM, the following equation was used.

Literature values
Value Units Species Notes Weight Reference
459 ppm Human Expression Vector: Skin

Enzyme: PHGPx pH: 7.5 Temperature: 37 °C

2048 [4]
307 ppm Human Expression Vector: Lung

Enzyme: PHGPx pH: 7.5 Temperature: 37 °C

1024 [4]
282 ppm Human Expression Vector: Esophagus

Enzyme: PHGPx pH: 7.5 Temperature: 37 °C

1024 [4]
204 ppm Human Expression Vector: Gut

Enzyme: PHGPx pH: 7.5 Temperature: 37 °C

1024 [5]
Description of the PHGPx concentration distribution
Mode (ppm) Mode (mM) Confidence Interval Location parameter (µ) Scale parameter (σ)
3.14E+02 1.74E-03 1.38E+00 5.85E+00 3.09E-01
The estimated probability distribution for PHGPx concentration. The value and weight of the literature values used to define the distribution are indicated by an orange dashed line. The x axis is plotted on a log-scale.

Keq

Literature values
Gibbs Free Energy Change Units Species Notes Weight Reference
(-26.941177) kcal/mol Not stated Estimated

Enzyme: PHGPx Substrate:a hydroperoxy-fatty-acyl-[lipid] Product: a hydroxy-fatty-acyl-[lipid] pH: 7.3 ionic strength: 0.25

64 [6]
Description of the PHGPx Keq distribution
Mode Confidence Interval Location parameter (µ) Scale parameter (σ)
5.90E+19 1.00E+01 4.63E+01 8.90E-01
The estimated probability distribution for PHGPx Keq. The value and weight of the literature values used to define the distribution are indicated by an orange dashed line. The x axis is plotted on a log-scale.

Related Reactions

  1. ↑ 1.0 1.1 Liu L. "Functional mimicry of the active site of glutathione peroxidase by glutathione imprinted selenium-containing protein. Biomacromolecules. 2008 Jan;9(1):363-8. doi: 10.1021/bm7008312. Epub 2007 Dec 29.
  2. ↑ 2.0 2.1 Zheng K. "A novel selenium-containing glutathione transferase zeta1-1, the activity of which surpasses the level of some native glutathione peroxidases. Int J Biochem Cell Biol. 2008;40(10):2090-7. doi: 10.1016/j.biocel.2008.02.006. Epub 2008 Feb 15.
  3. ↑ Hiratsuka A. "Subunit Ya-specific glutathione peroxidase activity toward cholesterol 7-hydroperoxides of glutathione S-transferases in cytosols from rat liver and skin. J Biol Chem. 1997 Feb 21;272(8):4763-9.
  4. ↑ 4.0 4.1 4.2 M. Wilhelm Mass-spectrometry-based draft of the human proteome Nature, 2014 509, 582–587
  5. ↑ M. Kim A draft map of the human proteome Nature, 2014 509, 575–581
  6. ↑ 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
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