Transformation of PGH2 to PGI2

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PGH2 is metabolised into the prostacyclin PGI2, by PGIS. This species has been associated with influencing the permeability of vascular compartment (Murata, Ushikubi et al. 1997). Similarly to the TX species, prostacyclins are only found in low concentration and are associated with infiltrating cells from the vascular compartment (Sugimoto, Arai et al. 2006).

Reaction

Chemical equation

$FA \rightleftharpoons AA$

Parameters

Michaelis-Menten Constants

Value	Units	Species	Notes	Reference
1.33E-02 ± 1.40E-03	$mM$	Human	Expression Vector: Bovine Endothelial and Aorta Cells Enzyme: Human PGIS pH:7.4 Temperature: 23
9.00E-03 ± 5.00E-03	$mM$	Bovine	Expression Vector: Bovine Endothelial and Aorta Cells Enzyme: Bovine PGIS pH:7.4 Temperature: 24

Enzyme Turnover Numbers

Value	Units	Species	Notes	Reference
147 ± 45	per minute	Cattle	Expression Vector: E. Coli Enzyme: Bovine PGIS pH:7.4 Temperature: 24

PGIS Abundance

Value	Units	Species	Notes	Reference
412	$ppm$	Human	Expression Vector: Urinary bladder Enzyme: PGIS pH: 7.5 Temperature: 37 °C
206	$ppm$	Human	Expression Vector: Lung Enzyme: PGIS pH: 7.5 Temperature: 37 °C
60.1	$ppm$	Human	Expression Vector: Esophagus Enzyme: PGIS pH: 7.5 Temperature: 37 °C
9.93	$ppm$	Human	Expression Vector: Oral Cavity Enzyme: PGIS pH: 7.5 Temperature: 37 °C

Gibbs Free Energy Change

Value	Units	Species	Notes	Reference
0.04	kcal/mol	Not stated	Estimated Enzyme: pgis Substrate: Arachidonate Product: PGI2 pH: 7.3 ionic strength: 0.25

Related Reactions

• Transformation of AA to PGH2
• Transformation of PGI2 to 6-K-PGF1α