WordNet

relating to or proceeding by autocatalysis
catalysis in which the catalyst is one of the products of the reaction

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/03/07 05:17:10」(JST)

wiki en

[Wiki en表示]

A single chemical reaction is said to have undergone autocatalysis, or be autocatalytic, if the reaction product itself is the catalyst for that reaction.

A set of chemical reactions can be said to be "collectively autocatalytic" if a number of those reactions produce, as reaction products, catalysts for enough of the other reactions that the entire set of chemical reactions is self-sustaining given an input of energy and food molecules (see autocatalytic set).

Rate law in autocatalytic reactions

Sigmoid variation of product concentration in autocatalytic reactions

The rate law for the second order autocatalytic reaction

is the following one

.

The concentrations of A and B vary in time according to

and

.

The graph for these equations is a sigmoid curve, which is typical for autocatalytic reactions: these chemical reactions proceed slowly at the start because there is little catalyst present, the rate of reaction increases progressively as the reaction proceeds as the amount of catalyst increases and then it again slows down as the reactant concentration decreases. If the concentration of a reactant or product in an experiment follows a sigmoid curve, the reaction is likely to be autocatalytic.

Abiogenesis hypothesis

In 1995 Stuart Kauffman proposed that life initially arose as autocatalytic chemical networks.^[1]

British ethologist Richard Dawkins wrote about autocatalysis as a potential explanation for abiogenesis in his 2004 book The Ancestor's Tale. He cites experiments performed by Julius Rebek and his colleagues at the Scripps Research Institute in California in which they combined amino adenosine and pentafluorophenyl ester with the autocatalyst amino adenosine triacid ester (AATE). One system from the experiment contained variants of AATE which catalysed the synthesis of themselves. This experiment demonstrated the possibility that autocatalysts could exhibit competition within a population of entities with heredity, which could be interpreted as a rudimentary form of natural selection.

Examples of autocatalytic reactions

Haloform reaction
Tin pest
Reaction of Permanganate with Oxalic Acid
The mechanism of the above reaction ^[2]
Vinegar syndrome
Binding of oxygen by hemoglobin
The spontaneous degradation of aspirin into salicylic acid and acetic acid, causing very old aspirin in sealed containers to smell mildly of vinegar.
The α-bromination of acetophenone with bromine.

Involvement in life processes

Autocatalysis plays a major role in the processes of life. Two researchers who have emphasised its role in the origins of life are Robert Ulanowicz ^[3] and Stuart Kauffman.^[4]

Autocatalysis occurs in the initial transcripts of rRNA. The introns are capable of excising themselves by the process of two nucleophilic transesterification reactions. The RNA able to do this sometimes referred to as a ribozyme. Additionally, the citric acid cycle is an autocatalytic cycle run in reverse.

Ultimately, biological metabolism itself can be seen as a vast autocatalytic set, in that all of the molecular constituents of a biological cell are produced by reactions involving this same set of molecules.

References

^ Stuart Kauffman (1995). At Home in the Universe: The Search for the Laws of Self-Organization and Complexity. Oxford University Press. ISBN 0-19-509599-5.
^ Kovacs KA, Grof P, Burai L, Riedel M (2004). "Revising the Mechanism of the Permanganate/Oxalate Reaction". J. Phys. Chem. A 108 (50): 11026. doi:10.1021/jp047061u.
^ Ecology, the Ascendent Perspective”, Robert Ulanowicz, Columbia Univ. Press 1997
^ Investigations, Stuart Kauffman.

External links

http://www.eeng.dcu.ie/~alife/bmcm9901/html-multi/
http://arxiv.org/pdf/adap-org/9809003

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 血栓溶解療法後の冠動脈再梗塞の予測因子 predictors of coronary artery reocclusion following fibrinolysis thrombolysis
2. 鎌状ヘモグロビン多量体：構造と機能特性 sickle hemoglobin polymer structure and functional properties
3. 遺伝性膵炎 hereditary pancreatitis
4. 慢性C型肝炎ウイルス感染の診断および評価 diagnosis and evaluation of chronic hepatitis c virus infection

English Journal

ADAMTS4 and its proteolytic fragments differentially affect melanoma growth and angiogenesis in mice.

Rao N, Ke Z, Liu H, Ho CJ, Kumar S, Xiang W, Zhu Y, Ge R.SourceDepartment of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore.
International journal of cancer. Journal international du cancer.Int J Cancer.2013 Jul 15;133(2):294-306. doi: 10.1002/ijc.28037. Epub 2013 Feb 12.
The metalloproteinase ADAMTS4 (ADAMTS, a disintegrin-like and metalloproteinase with thrombospondin motif)/aggrecanase-1 is highly expressed in cartilage and has been implicated in human arthritis. Although abundantly expressed in many types of cancer, its role in cancer remains unknown. In this wor
PMID 23319426

HIPK2 catalytic activity and subcellular localization are regulated by activation-loop Y354 autophosphorylation.

Siepi F, Gatti V, Camerini S, Crescenzi M, Soddu S.SourceDipartimento di Oncologia Sperimentale, Istituto Nazionale Tumori Regina Elena, 00158, Roma, Italy. Electronic address: siepi@ifo.it.
Biochimica et biophysica acta.Biochim Biophys Acta.2013 Jun;1833(6):1443-53. doi: 10.1016/j.bbamcr.2013.02.018. Epub 2013 Feb 26.
HIPK2 (homeodomain-interacting protein kinase-2) binds to and phosphorylates, at Ser and Thr residues, a large number of targets involved in cell division and cell fate decision in response to different physiological or stress stimuli. Inactivation of HIPK2 has been observed in human and mouse cance
PMID 23485397

Myelin basic protein: Structural characterization of spherulites formation and preventive action of trehalose.

Di Salvo C, Barreca D, Laganà G, di Bella M, Tellone E, Ficarra S, Bellocco E.SourceDipartimento di Scienze Chimiche, Università di Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy.
International journal of biological macromolecules.Int J Biol Macromol.2013 Jun;57:63-8. doi: 10.1016/j.ijbiomac.2013.02.022. Epub 2013 Mar 13.
Myelin basic protein (MBP) is one of the main protein components of central nervous system that as shown in our work, under appropriate condition, forms spherulites. The structural and morphological features of these elements and the ability of trehalose to decrease or completely avoid their formati
PMID 23500430

Japanese Journal

超長命性でかつエチレン低感受性のカーネーション系統 806-46b の選抜

小野崎隆,八木雅史,棚瀬幸司
The Horticulture Journal 84(1), 58-68, 2015
花持ち性は，切り花を購入する消費者にとって最も重要な特性のひとつであり，花持ち性の遺伝的な改良が望まれている．著者らは交雑育種によるカーネーションの花持ち性の向上に関する研究を 1992 年より行ってきた．花持ち性が極めて優れ，かつ，エチレン低感受性の系統を開発するために，2003 年から 2010 年まで 3 世代にわたる交配と選抜を行った．2010 年に，系統 606-65S と 609-63 …
NAID 130005065754

油滴の微細化がO/Wエマルション系での脂質酸化に及ぼす影響

菊池耕士,山本修一,四日洋和,吉井英文,安達修二
日本食品工学会誌 15(2), 43-47, 2014
O/Wエマルション系における脂質酸化に及ぼす油滴径の影響は，次のように考えるのが一般的であろう．油滴径が大きいと比表面積が小さく，油水界面での酸素の物質移動の影響により酸化が遅延される．一方，油滴が微細化すると，油水界面を通して十分量の酸素が供給されるので，反応自体が律速となり，脂質の酸化速度は油滴径に依存しない．しかし，既往の論文では，油滴を微細化すると酸化が促進されるとするもの[1-5]と，逆 …
NAID 130004692127