Inositol trisphosphate
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Surname | Inositol trisphosphate | |||||||||
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Molecular formula | C 6 H 15 O 15 P 3 | |||||||||
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properties | ||||||||||
Molar mass | 420.10 g mol −1 | |||||||||
Physical state |
firmly |
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As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . |
Inositol trisphosphate (also inositol-1,4,5-trisphosphate , IP 3 for short ) is an inositol phosphate with three phosphate groups in biochemistry - it is released from a phospholipid and is important as a secondary messenger substance for signal transmission ( signal transduction ) in the cell .
Biosynthesis and other reactions
By activating a G-protein-coupled receptor or a tyrosine kinase , the membrane-bound phospholipase C is stimulated. This splits the membrane lipid phosphatidylinositol-4,5-bisphosphate (PIP 2 ) to diacylglycerol (DAG) and inositol trisphosphate.
Inositol trisphosphate is deactivated in the cell metabolism by IP 3 phosphatase to inositol bite phosphate. A further phosphorylation by the IP 3 -3-kinase (EC 2.7.1.127, three isoforms: A, B and C) at the 3-position initiates a reaction chain to further, more highly phosphorylated inositol phosphates, which also have functions in the regulation of the cell could meet.
See also
- Signaling pathways of insulin
- Inositol 1,4,5-trisphosphate (IP 3 ) as second messenger
- Function of phospholipase C
- Signal transduction in protein kinase C.
- Endoplasmic reticulum as calcium storage
function
Inositoltrisphosphate effected through binding to its specific receptor , the IP3-receptor , the release of calcium - ions from the endoplasmic reticulum , which serves as an intracellular calcium storage. The resulting increase in the concentration of calcium in the cytosol has a variety of physiological functions. These include:
- the contraction of the smooth muscles due to the fact that calmodulin forms a complex with the myosin light chain kinase, which causes a phosphorylation of the myosin light chain with subsequent contraction
- the activation of protein kinase C (PKC) by 1,2-diacylglycerol, whereby the myosin light chain phosphatase is inhibited and thus the effect of the contraction is increased
- the calmodulin -dependent activation of protein kinases .
Individual evidence
- ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
- ^ RF Schmidt, G. Thews: Physiologie des Menschen . Springer, 2013, ISBN 978-3-642-87854-1 , pp. 18 ( limited preview in Google Book search).
- ↑ a b c Rosemarie Baumann: Physiology . Georg Thieme Verlag, 2010, ISBN 978-3-13-796006-5 , p. 41, 121 ( limited preview in Google Book search).
- ↑ Georg Löffler: Basic knowledge of biochemistry with pathobiochemistry . Springer-Verlag, 2013, ISBN 978-3-662-05984-5 , pp. 486 ( limited preview in Google Book search).