Adenine
IUPAC name 9H-purin-6-amine
Other names 6-aminopurine
Identifiers
CAS number	73-24-5 Y
PubChem	190
ChemSpider	185 Y
UNII	JAC85A2161 Y
DrugBank	DB00173
KEGG	D00034 Y
ChEBI	CHEBI:16708 Y
ChEMBL	CHEMBL226345 Y
Jmol-3D images	Image 1 Image 2
SMILES n1c(c2c(nc1)ncn2)N c1[nH]c2c(ncnc2n1)N
InChI InChI=1S/C5H5N5/c6-4-3-5(9-1-7-3)10-2-8-4/h1-2H,(H3,6,7,8,9,10) Y Key: GFFGJBXGBJISGV-UHFFFAOYSA-N Y InChI=1/C5H5N5/c6-4-3-5(9-1-7-3)10-2-8-4/h1-2H,(H3,6,7,8,9,10) Key: GFFGJBXGBJISGV-UHFFFAOYAT
Properties
Molecular formula	C5H5N5
Molar mass	135.13 g/mol
Appearance	white, crystalline
Density	1.6 g/cm3 (calculated)
Melting point	360–365 °C (decomposes)
Acidity (pKa)	4.15 (secondary), 9.80 (primary)[1]
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Adenine (A, Ade) is a nucleobase (a purine derivative) with a variety of roles in biochemistry including cellular respiration, in the form of both the energy-rich adenosine triphosphate (ATP) and the cofactors nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD), and protein synthesis, as a chemical component of DNA and RNA.^[2] The shape of adenine is complementary to either thymine in DNA or uracil in RNA.

Structure[link]

Adenine structure, with standard numbering of positions in red.

Adenine forms several tautomers, compounds that can be rapidly interconverted and are often considered equivalent.^{[citation needed]} However, in isolated conditions, i.e. in an inert gas matrix and in the gas phase, mainly the 9H-adenine tautomer is found.^[3][4]

Biosynthesis[link]

Purine metabolism involves the formation of adenine and guanine. Both adenine and guanine are derived from the nucleotide inosine monophosphate (IMP), which is synthesised on a pre-existing ribose phosphate through a complex pathway using atoms from the amino acids glycine, glutamine, and aspartic acid, as well as fused with the enzyme tetrahydrofolate.

In Saccharomyces cerevisiae (yeast), the adenine pathway converts P-ribosyl-PP into adenine through a seven-step process.

Function[link]

Adenine is one of the two purine nucleobases (the other being guanine) used in forming nucleotides of the nucleic acids. In DNA, adenine binds to thymine via two hydrogen bonds to assist in stabilizing the nucleic acid structures. In RNA, which is used for protein synthesis, adenine binds to uracil.

Adenine forms adenosine, a nucleoside, when attached to ribose, and deoxyadenosine when attached to deoxyribose. It forms adenosine triphosphate (ATP), a nucleotide, when three phosphate groups are added to adenosine. Adenosine triphosphate is used in cellular metabolism as one of the basic methods of transferring chemical energy between chemical reactions.

History[link]

In older literature, adenine was sometimes called Vitamin B₄.^[5] It is no longer considered a true vitamin or part of the Vitamin B complex. However, two B vitamins, niacin and riboflavin, bind with adenine to form the essential cofactors nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD), respectively. Hermann Emil Fischer was one of the early scientists to study adenine.

It was named in 1885 by Albrecht Kossel, in reference to the pancreas (a specific gland - in Greek, "aden") from which Kossel's sample had been extracted.^[6]

Experiments performed in 1961 by Joan Oró have shown that a large quantity of adenine can be synthesized from the polymerization of ammonia with five hydrogen cyanide (HCN) molecules in aqueous solution;^[7] whether this has implications for the origin of life on Earth is under debate.^[8]

On August 8, 2011, a report, based on NASA studies with meteorites found on Earth, was published suggesting building blocks of DNA and RNA (adenine, guanine and related organic molecules) may have been formed extraterrestrially in outer space.^[9][10][11] In 2011, physicists reported that adenine has an "unexpectedly variable range of ionization energies along its reaction pathways" which suggested that "understanding experimental data on how adenine survives exposure to UV light is much more complicated than previously thought"; these findings have implications for spectroscopic measurements of heterocyclic compounds, according to one report.^[12]

References[link]

Michael J. Sandel (born March 5, 1953) is an American political philosopher and a professor at Harvard University. He is best known for the Harvard course 'Justice', which is available to view online, and for his critique of John Rawls' A Theory of Justice in his Liberalism and the Limits of Justice (1982). He was elected a Fellow of the American Academy of Arts and Sciences in 2002.^[1]

Education[link]

Born in Minneapolis to a Jewish family, which moved to Los Angeles when he was thirteen. A high achiever, he was the President of his senior class at Palisades High School (1971), graduated Phi Beta Kappa from Brandeis University (1975), and received his doctorate from Balliol College, Oxford, as a Rhodes Scholar, where he studied under philosopher Charles Taylor.

Philosophical views[link]

Sandel subscribes to a certain version of communitarianism (although he is uncomfortable with the label), and in this vein he is perhaps best known for his critique of John Rawls's A Theory of Justice. Rawls' argument depends on the assumption of the veil of ignorance, which he claims allows us to become "unencumbered selves".

Sandel's view is that we are by nature encumbered to an extent that makes it impossible even in the hypothetical to have such a veil. Some examples of such ties are the ties we make with our families, which we do not make by conscious choice but are born with them already attached. Because they are not consciously applied, these ties are impossible to separate from someone. Sandel believes that only a less-restrictive, looser version of the veil of ignorance can be possible. Rawls's argument, however, depends on the fact that the veil is restrictive enough that we make decisions without knowing who will be affected by these decisions, which of course is impossible if we are already attached to people in the world.

Teaching[link]

Justice[link]

Sandel has taught the famous "Justice"^[2] course at Harvard for two decades. More than 15,000 students have taken the course, making it one of the most highly attended in Harvard's history. The fall 2007 class was the largest ever at Harvard, with a total of 1,115 students.^[3] The fall 2005 course was recorded, and is offered online for students through the Harvard Extension School. An abridged form of this recording is now a 12-episode TV series, Justice: What's the Right Thing to Do?, in a co-production of WGBH and Harvard University. Episodes are available on the Justice with Michael Sandel website.^[4][5] There is also an accompanying book, Justice: What's the Right Thing to Do?, and the sourcebook of readings Justice: A Reader.

The popularity of the show is attributed to the discussion-oriented format (the Socratic method)—rather than recitation and memorization of facts—and to Sandel's engaging style, incorporating context into discussion; for example, starting one lecture with a discussion of the ethics of ticket scalping.^[6]

The BBC broadcast eight 30-minute segments from the series on BBC Four starting on 25 January 2011.^[7]

In April 2012, BBC Radio 4 broadcast a three-part series presented by Professor Sandel titled The Public Philosopher. These followed a format similar to the Justice lectures, this time recorded in front of an audience at the London School of Economics. Across three programmes, Sandel debates with the audience whether universities should give preference to students from poorer backgrounds; whether a nurse should be paid more than a banker; and whether it is right to bribe people to be healthy. The programmes were made available for download via the BBC podcast Michael Sandel: The Public Philosopher.

Other teaching[link]

Sandel also co-teaches with Douglas Melton "Ethics and Biotechnology", a seminar considering the ethical implications of a variety of biotechnological procedures and possibilities.

Authorship[link]

Sandel is the author of multiple publications including Democracy's Discontent and Public Philosophy. His Public Philosophy is a collection of his own previously published essays, examining the role of morality and justice in American political life. He offers commentary on the roles of moral values and civic community in the American electoral process – a much-debated aspect of the 2004 U.S. election cycle and current political discussion.

Michael Sandel gave the 2009 Reith Lectures on "A New Citizenship" on BBC Radio, addressing the 'prospect for a new politics of the common good'.^[8] The lectures were delivered in London on May 18, Oxford on May 21, Newcastle on May 26, and Washington, D.C., in early June.^[9]

Public service[link]

Sandel served on the George W. Bush administration's President's Council on Bioethics.

2009 immigration commentary[link]

In 2009, Sandel criticized Nobel Prize-winning economist Gary Becker's free-market immigration proposal. This proposed solution entailed imposing refugee quotas on nations according to their wealth and then allowing countries to pay other, poorer countries to take refugees allotted under their quota.^[10] Sandel concludes that "a market in refugees changes our view of who refugees are and how they should be treated. It encourages the participants — the buyers, the sellers and also those whose asylum is being haggled over — to think of refugees as burdens to be unloaded or as revenue sources rather than as human beings in peril."^[11]

Montgomery Burns character[link]

There is an urban legend that Sandel was the inspiration for the Montgomery Burns character in The Simpsons. The joke, of course, is that Sandel could be the anti-Burns: a moral philosopher who has devoted his life to pondering what is the right thing to do. The rumor derives from the facts that (1) several future writers for Fox’s “Simpsons” likely took his popular course "Justice" at Harvard, (2) Sandel used to make Mr. Burns' hand gesture (before Mr. Burns did), and (3) he shares a receding hairline with the evil-minded cartoon character.^[12][13] The connection has been denied by Simpsons writers.^[14]

Works[link]

• Michael J. Sandel, What Money Can't Buy: The Moral Limits of Markets, Farrar, Straus and Giroux, (April 24, 2012), ISBN 978-0-374-20303-0
• Michael J. Sandel, Justice: What's the Right Thing to Do?, Farrar, Straus and Giroux, (September 15, 2009), ISBN 978-0-374-18065-2
• Michael J. Sandel, Justice: A Reader, Oxford University Press, (September 27, 2007), ISBN 978-0-19-533512-5
• Michael J. Sandel, The Case against Perfection: Ethics in the Age of Genetic Engineering, Belknap Press of Harvard University Press, (January 31, 2007); paperback (September 30, 2009), ISBN 978-0-674-03638-3
• Michael J. Sandel, Public Philosophy: Essays on Morality in Politics, Harvard University Press (October 31, 2006), ISBN 978-0-674-02365-9
• Michael J. Sandel, Liberalism and the Limits of Justice, Cambridge University Press, (March 28, 1998), ISBN 978-0-521-56741-1
• Michael J. Sandel, Democracy's Discontent: America in Search of a Public Philosophy, Belknap Press of Harvard University Press (February 6, 1998), ISBN 978-0-674-19745-9

Other languages

• Michael J. Sandel, Plädoyer gegen die Perfektion (German), Berlin University Press, (January 1, 2008), ISBN 978-3-940432-14-8
• Michael J. Sandel and Maria Luz Melon, El Liberalismo y los Limites de la Justicia (Filosofia del Derecho) (Spanish), Gedisa Editorial, (November 2000), ISBN 978-84-7432-706-9
• Michael J. Sandel, これからの「正義」の話をしよう――いまを生き延びるための哲学(Japanese),早川書房, (May 5, 2010), ISBN 978-4-15-209131-4; translation of "Justice: What's the Right Thing to Do?", Farrar, Straus and Giroux, (September 15, 2009)
• Michael J. Sandel, "정의란 무엇인가", 서울: 김영사, (Korean) (May 17, 2010), ISBN 978-89-349-3960-3; translation of "Justice: What's the Right Thing to Do?", Farrar, Straus and Giroux, (September 15, 2009)
• Michael J. Sandel, 正義：一場思辨之旅 (Traditional Chinese),雅言文化, (March 1, 2011), ISBN 978-986-82712-6-5; translation of "Justice: What's the Right Thing to Do?", Farrar, Straus and Giroux, (September 15, 2009)
• Michael J. Sandel, 公正：该如何做是好？ (Simplified Chinese),中信出版社, (June, 2011), ISBN 978-7-5086-2755-7; translation of "Justice: What's the Right Thing to Do?", Farrar, Straus and Giroux, (September 15, 2009)

See also[link]

• American philosophy
• List of American philosophers

References[link]

External links[link]

• Harvard University Bio
• Podcast interview with Nigel Warburton on Philosophy Bites on What Shouldn't Be Sold
• Podcast interview with Nigel Warburton on Ethics Bites on the topic of Genetic Enhancement in Sports
• The President's Council on Bioethics
• FORA.tv The Case Against Perfection
• FORA.tv Michael Sandel on Justice: A Journey in Moral Reasoning at the Aspen Institute, one hour excerpt
• A page of links relating to the 2009 Reith Lectures
• Justice with Michael Sandel, WGBH Boston and Harvard University, complete online video with discussion guides, readings and discussion circle
• Justice: What's The Right Thing To Do? on Harvard University's YouTube channel
• Fairness and the Big Society Debate on BBC
• Justice: a series of lectures by Michael Sandel on BBC
• 12 Questions with Michael Sandel: An Art of Theory Interview
• Booknotes interview with Sandel on Democracy's Discontent: America in Search of a Public Philosophy, May 19, 1996.