“Coacervate”的意思、由来-开放百科全书

Coacervates ({{IPAc-en|k|oʊ|ə|ˈ|s|ɜr|v|ə|t|s}} or {{IPAc-en|k|oʊ|ˈ|æ|s|ər|v|eɪ|t|s}}) are organic-rich droplets formed via liquid-liquid phase separation, mainly resulting from association of oppositely charged molecules (such as macro-ions, polyelectrolytes, polysaccharides, protein etc.)^[1] or from hydrophobic molecules/ proteins (such as elastin-like polypeptides)^[2]. Coacervation is a phenomenon that produces coacervate colloidal droplets. When coacervation happens, two liquid phase will co-exist: a dense polymer rich phase (coacervate phase or coacervate droplets) and a very dilute polymer deficient phase (dilute phase). Coacervate droplets can measure from 1 to 100 micrometres across, while their soluble precursors^[3]^[4] are typically on the order of less than 200 nm.^[5] The name "coacervate" derives from the Latin coacervare, meaning "to assemble together or cluster".

The process of coacervation^[6] was famously proposed by Alexander Oparin and J. B. S. Haldane as crucial in his early theory of abiogenesis (origin of life/proiskhozhdenie zhizni). This theory proposes that metabolism predated information replication, although the discussion as to whether metabolism or molecules capable of template replication came first in the origins of life remains open^[7] and for decades the theory of Oparin and Haldane was the leading approach to the origin of life question.

History

These structures were first investigated by the Dutch chemist H.G. Bungenberg de Jong, in 1932.{{Citation needed|date = May 2015}} A wide variety of solutions can give rise to them; for example, coacervates form spontaneously when a disordered polypeptide, such as gelatin, reacts with another biologically derived polyelectrolyte, such as gum arabic. They are interesting not only in that they provide a locally segregated environment, but also in that their boundaries allow the selective absorption of simple organic molecules from the surrounding medium. For example, a mix of carbohydrate solution with a protein solution, will favor the spontaneous formation of amoeba-like coacervates which change shape, merge, divide, form "vacuoles", release "vacuole contents", and show other lifelike properties.^[8] In Oparin's view this amounts to an elementary form of metabolism. British scientist Bernal commented that they are "the nearest we can come to cells without introducing any biological – or, at any rate, any living biological – substance." However, the lack of any mechanism by which coacervates can reproduce leaves them far short of being living systems.^[9]

Complex coacervation

See also

References

1. ^{{Citation|last=Aumiller|first=William M.|title=Phase Separation as a Possible Means of Nuclear Compartmentalization|date=2014|url=http://dx.doi.org/10.1016/b978-0-12-800046-5.00005-9|work=International Review of Cell and Molecular Biology|pages=109–149|publisher=Elsevier|isbn=9780128000465|access-date=2019-02-09|last2=Davis|first2=Bradley W.|last3=Keating|first3=Christine D.}}
2. ^{{Cite journal|last=Sharpe|first=Simon|last2=Keeley|first2=Fred W.|last3=Muiznieks|first3=Lisa D.|last4=Reichheld|first4=Sean E.|date=2017-05-30|title=Direct observation of structure and dynamics during phase separation of an elastomeric protein|url=https://www.pnas.org/content/114/22/E4408|journal=Proceedings of the National Academy of Sciences|language=en|volume=114|issue=22|pages=E4408–E4415|doi=10.1073/pnas.1701877114|issn=0027-8424|pmc=5465911|pmid=28507126}}
3. ^{{cite journal|first1=J.J.|last1=Water|first2=M.M.|last2=Schack|first3=A.|last3=Velazquez-Campoy|first4=M.J.|last4=Maltesen|first5=M. |last5=van de Weert|first6=L. |last6=Jorgensen|title=Complex coacervates of hyaluronic acid and lysozyme: Effect on protein structure and physical stability|journal=European Journal of Pharmaceutics and Biopharmaceutics|doi=10.1016/j.ejpb.2014.09.001|volume=88|pages=325–331}}
4. ^Definition of coacervate, Memidex dictionary.
5. ^{{cite journal| last1=Schmitt| first1=Christophe| last2=Turgeon| first2=Sylvie L.| title=Protein/polysaccharide complexes and coacervates in food systems| journal=Advances in Colloid and Interface Science| doi=10.1016/j.cis.2010.10.001| volume=167| pages=63–70}}
6. ^Bungenberg de Jong, H. G., and H. R. Kruyt (1929). "Coacervation (partial miscibility in colloid systems)". Proc Koninklijke Nederlandse Akademie Wetenschappen 32: 849—856
7. ^Origins of Life and Evolution of the Biosphere, Volume 40, Numbers 4-5, October 2010 , pp. 347–497(151)
8. ^Creating Coacervates. Larry Flammer, Indiana State University.
9. ^{{cite book |author= Dick, Steven J. |title=The Biological Universe: The Twentieth Century Extraterrestrial Life Debate and the Limits of Science |publisher=Cambridge University Press |location= |year=1999 |pages=340|isbn=978-0-521-66361-8 }}
10. ^{{cite journal| last1=Kizilay| first1=E| title=Complexation and coacervation of polyelectrolytes with oppositely charged colloids.| journal=Adv Colloid Interface Sci.| date=Sep 14, 2011|volume=167| pages=24–37| doi=10.1016/j.cis.2011.06.006}}
11. ^Research — Complex Coacervates, Tirrell Research Group.
12. ^{{Cite book|url=http://doi.wiley.com/10.1002/9781119290971.ch7|title=Advances in Chemical Physics|last=Srivastava|first=Samanvaya|last2=Tirrell|first2=Matthew V.|publisher=Wiley-Blackwell|pages=499–544|language=en|doi=10.1002/9781119290971.ch7}}