Transformation of AA to 12-HPETE

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LOX enzymes oxidise AA to generate hydroxy fatty acids. In the skin, the 12-LOX isoform of LOX is more active than others. This isoform is highly expressed in the resident cells of both compartments, epidermal keratinocytes and dermal fibroblasts (Dowd, Kobza Black et al. 1985). The 12- LOX enzyme catalyses the addition of O2 at the C-12 position of AA, producing 12-HPETE.

Reaction

Chemical equation

$AA \rightleftharpoons PGH2$

Rate equation

12-LOX Parameters

Michaelis-Menten Constants

Value	Units	Species	Notes	Reference
7.20E-03	$mM$	Human	Expression Vector: Platelet Enzyme: 12-Lipoxygenase pH: 7.4 Temperature: 37°C.
8.00E-02	$mM$	Human	Expression Vector: Platelet Enzyme: 12-Lipoxygenase pH: 7 Temperature: 24
1.00E-02	$mM$	Human Platlet	Expression Vector: Baculovirus Enzyme: 12-Lipoxygenase pH: 8 Temperature: 37
7.90E-03 ± 8.00E-04	$mM$	Human	Expression Vector: Platelets Enzyme:12-Lipoxygenase pH: 7.4 Temperature: 37

Enzyme Turnover Numbers

Value	Units	Species	Notes	Reference
336 ± 12	per minute	Human	Expression Vector: Human reticulocyte Enzyme: 15-lipoxygenase-1 pH: 7.5 Temperature: 25
504	per minute	Wild Boar	Expression Vector: E. coli. Enzyme: 12-Lipoxygenase pH: 7.4 Temperature: 37

12-LOX Abundance

Value	Units	Species	Notes	Reference
19.8	$ppm$	Human	Expression Vector: Spleen Enzyme: 12-LOX pH: 7.5 Temperature: 37 °C
1.60	$ppm$	Human	Expression Vector: Liver Enzyme: 12-LOX pH: 7.5 Temperature: 37 °C
0.28	$ppm$	Human	Expression Vector: Gut Enzyme: 12-LOX pH: 7.5 Temperature: 37 °C
0.11	$ppm$	Human	Expression Vector: Pancreas Enzyme: 12-LOX pH: 7.5 Temperature: 37 °C

Gibbs Free Energy Change

Value	Units	Species	Notes	Reference
(-69.979996)	kcal/mol	Not stated	Estimated Enzyme: 12-LOX Substrate: Arachidonate Product: 12-HPETE pH: 7.3 ionic strength: 0.25