Thromboxane A2

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Structural formula
Structural formula of thromboxane-A2
General
Surname Thromboxane A2
other names
  • (5 Z , 9α, 11α, 13 E , 15 S ) -9,11-epoxy-15-hydroxythromboxa-5,13-diene-1-acid
  • TXA 2
Molecular formula C 20 H 32 O 5
External identifiers / databases
CAS number 57576-52-0
PubChem 5280497
ChemSpider 4444137
Wikidata Q774909
properties
Molar mass 352.47 g mol −1
safety instructions
GHS hazard labeling
no classification available
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Thromboxane A 2 (or TXA 2 for short ) is an eicosanoid related to the prostaglandins , which occurs mainly in thrombocytes (blood platelets) and is named after them. It contains an oxane ring made of five carbon and one oxygen atoms. Prostaglandin H 2 is initially formed from the precursor arachidonic acid by cyclooxygenase and peroxidase . The thromboxane synthase finally produces thromboxane A 2 from this.

effect

Thromboxane A 2 mediates its effects via the thromboxane receptor , a membrane-bound G-protein-coupled receptor . The active thromboxane-A 2 is broken down in the body with a half-life of 30 seconds to the inactive metabolite thromboxane-B 2 .

Thromboxane-B 2 , the inactive breakdown product of thromboxane-A 2 .
  • Platelet aggregation : TXA 2 is formed in platelets , among other things , and is the main prostaglandin there. It activates platelet aggregation via the thromboxane receptors on the platelets and is an antagonist of the blood-clotting prostacyclin formed by the endothelium . Platelets only contain cyclooxygenase-1 for prostaglandin formation. This is irretrievably rendered inoperable by acetylsalicylic acid and can then not be regenerated in platelets (since these are nucleated). Therefore, for the rest of their eight to twelve day life in the organism, even after small doses of acetylsalicylic acid, these platelets are clearly restricted in their ability to aggregate .
  • Smooth muscles : TXA 2 also causes all smooth muscles in blood vessels and airways to contract via the thromboxane receptors.

Individual evidence

  1. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
  2. ↑ Florian Horn: Biochemistry of humans. The textbook for medical studies . Georg Thieme Verlag, Stuttgart, New York 2009, ISBN 978-3-13-130884-9 , pp. 414 ff .
  3. ↑ Simmons D et al. Cyclooxygenase Isoenzymes: The Biology of Prostaglandin Synthesis and Inhibition. Pharmacol. Rev. 2004, 56, pp. 387-437.