Polyamine


Polyamine

[
thumb|spermine] The polyamines are organic compounds having two or more primary amino groups - such as putrescine, cadaverine, spermidine, and spermine - that are growth factors in both eucaryotic and procaryotic cells.

Cyclen is the main representative of a class of cyclic polyamines. Polyethylene amine is a polymer based on aziridine monomer.

Functions

Though it is known that polyamines are synthesized in cells via highly-regulated pathways, their actual function is not entirely clear. As cations, they bind to DNA, and, in structure, they represent compounds with cations that are found at "regularly-spaced intervals" (unlike, say, Mg++ or Ca++, which are point charges).

If cellular polyamine synthesis is inhibited, cell growth is stopped or severely retarded. The provision of exogenous polyamines restores the growth of these cells. Most eukaryotic cells have a polyamine transporter system on their cell membrane that facilitates the internalization of exogenous polyamines. This system is highly active in rapidly proliferating cells and is the target of some chemotherapeutics currently under development. [Wang, C.; Delcros, J.-G.; Cannon, L.; Konate, F.; Carias, H.; Biggerstaff, J.; Gardner, R.; Phanstiel, O. Defining the molecular requirements for the selective delivery of polyamine-conjugates into cells containing active polyamine transporters. J. Med. Chem. 2003, 46, 5129-5138.]

Polyamines are also important modulators of a variety of ion channels, including NMDA receptors and AMPA receptors. They block inward-rectifier potassium channels so that the currents of the channels are inwardly rectified, thereby the cellular energy, i.e. K+ ion gradient across the cell membrane, is conserved.

ynthesis of linear polyamines

Putrescine

Putrescine is synthesized biologically via two different pathways, both starting from arginine.
* In one pathway, arginine is converted into agmatine, with a reaction catalyzed by the enzyme arginine decarboxylase (ADC); then agmatine is transformed into carbamilputrescine by agmatine imino hydroxylase (AIH). Finally, carbamilputrescine is converted into putrescine.
* In the second pathway, arginine is converted into ornithine and then ornithine is converted into putrescine by ornithine decarboxylase (ODC).

Cadaverine

Cadaverine is synthesized from lysine in a one-step reaction with lysine decarboxylase (LDC).

permidine and spermine

Spermidine is synthesized from putrescine, using an aminopropylic group from decarboxylated S-adenosyl-L-methionine (SAM). The reaction is catalyzed by spermidine synthase.

Spermine is synthesized from the reaction of spermidine with SAM in the presence of the enzyme spermine synthase .

References

External links

* [http://www.biol.lu.se/zoofysiol/Cellprolif/Research/research_area_1.html Polyamines in cell cycle proliferation and cell death]

* [http://herkules.oulu.fi/isbn9514266315/html/index.html Ornithine Decarboxylase: Expression and regulation in rat brain and in transgenic mice, 2002, Pekka Kilpelainen, Department of Biochemistry, University of Oulu. Extensive review of literature through 2001 on polyamine structure, properties, metabolism in mammals, and physiological and pathophysiological roles (See article Table of Contents)]


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  • polyamine — [ pɔliamin ] n. f. • 1898; de poly et amine ♦ Chim., biol. Substance aliphatique linéaire possédant plusieurs fonctions amine. ● polyamine nom féminin Composé chimique renfermant plusieurs fonctions amine. polyamine n. f. CHIM Corps possédant… …   Encyclopédie Universelle

  • Polyamine — Unter Polyamine werden meist gesättigte, offenkettige oder cyclische organische Verbindungen zusammenfasst, mit endständigen Aminogruppen, unterbrochen von einer wechselnden Anzahl sekundärer Aminogruppen.[1] Polyamine sind je nach Kettenlänge… …   Deutsch Wikipedia

  • Polyamine — Putrescine ou diaminobutane, une polyaamine qui participe à donner aux cadavres en décomposition leur odeur. Les polyamines sont des composés organiques possédant deux ou plusieurs fonctions amine. Parmi les composés répondant à cette définition …   Wikipédia en Français

  • polyamine — “+ noun Etymology: International Scientific Vocabulary poly + amine : a compound characterized by more than one amino group * * * /pol ee euh meen , am in/, n. Chem. a compound containing more than one amino group. [1860 65; POLY + AMINE] * * *… …   Useful english dictionary

  • polyamine — noun Date: 1861 a compound characterized by more than one amino group …   New Collegiate Dictionary

  • polyamine — Polycations at physiological pH, polyamines can bind and interact with various other molecules within the cell. In particular interact with DNA but also may modulate ion channels and act as growth factors. Spermine has four positive charges,… …   Dictionary of molecular biology

  • polyamine — /pol ee euh meen , am in/, n. Chem. a compound containing more than one amino group. [1860 65; POLY + AMINE] * * * …   Universalium

  • polyamine — noun any compound having many (more than three) amino functional groups …   Wiktionary

  • polyamine — Class name for substances of the general formula H2N(CH2)nNH2, H2N(CH2)nNH(CH2)nNH2, H2N(CH2)nNH(CH2)nNH(CH2)nNH2, where n = 3, 4, or 5. Many polyamines arise by bacterial …   Medical dictionary

  • polyamine — n. compound containing more than one of the amino acid groups (Chemistry) …   English contemporary dictionary


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