Editing Enzyme (section)

== Etymology and history ==
By the late 17th and early 18th centuries, the digestion of [[meat]] by stomach secretions<ref name="Reaumur1752">{{cite journal |author-link=René Antoine Ferchault de Réaumur |vauthors=de Réaumur RA |year=1752 |title=Observations sur la digestion des oiseaux |url=https://gallica.bnf.fr/ark:/12148/bpt6k35505/f452.item |journal=Histoire de l'Académie Royale des Sciences |language=fr |volume=1752 |pages=266, 461}}</ref> and the conversion of [[starch]] to [[sugar]]s by plant extracts and [[saliva]] were known but the mechanisms by which these occurred had not been identified.<ref>{{cite book | url = http://etext.lib.virginia.edu/toc/modeng/public/Wil4Sci.html | vauthors = Williams HS | title = A History of Science: in Five Volumes''. ''Volume IV: Modern Development of the Chemical and Biological Sciences | publisher = Harper and Brothers | year = 1904 }}</ref><!--adjacent info: [[Jöns Jacob Berzelius]], [[α-Amylase#Salivary_amylase_(ptyalin)]], [[amylase#History]]-->

French chemist [[Anselme Payen]] was the first to discover an enzyme, [[diastase]], in 1833.<ref>{{cite journal | vauthors = Payen A, Persoz JF | year = 1833 | title = Mémoire sur la diastase, les principaux produits de ses réactions et leurs applications aux arts industriels | language = fr | trans-title = Memoir on diastase, the principal products of its reactions, and their applications to the industrial arts | journal = Annales de chimie et de physique | series = 2nd | volume = 53 | url = https://books.google.com/books?id=Q9I3AAAAMAAJ&pg=PA73 | pages = 73–92}}</ref> A few decades later, when studying the [[fermentation (food)|fermentation]] of sugar to [[ethanol|alcohol]] by [[yeast]], [[Louis Pasteur]] concluded that this fermentation was caused by a [[vital force]] contained within the yeast cells called "ferments", which were thought to function only within living organisms. He wrote that "alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells."<ref>{{cite journal | vauthors = Manchester KL | title = Louis Pasteur (1822–1895)--chance and the prepared mind | journal = Trends in Biotechnology | volume = 13 | issue = 12 | pages = 511–515 | date = December 1995 | pmid = 8595136 | doi = 10.1016/S0167-7799(00)89014-9 }}</ref>

In 1877, German physiologist [[Wilhelm Kühne]] (1837–1900) first used the term ''[[wiktionary:enzyme|enzyme]]'', which comes {{ety|grc|''[[wikt:ένζυμο|ἔνζυμον]]'' (énzymon)|[[Bread#Leavening|leavened]], in yeast}}, to describe this process.<ref>Kühne coined the word "enzyme" in: {{cite journal | vauthors = Kühne W | year = 1877 | url = https://books.google.com/books?id=jzdMAAAAYAAJ&pg=PA190 | language = de | title = Über das Verhalten verschiedener organisirter und sog. ungeformter Fermente | trans-title = On the behavior of various organized and so-called unformed ferments | journal = Verhandlungen des Naturhistorisch-medicinischen Vereins zu Heidelberg | series = new series | volume = 1 | issue = 3 | pages = 190–193 }} Relevant passage on page 190: ''"Um Missverständnissen vorzubeugen und lästige Umschreibungen zu vermeiden schlägt Vortragender vor, die ungeformten oder nicht organisirten Fermente, deren Wirkung ohne Anwesenheit von Organismen und ausserhalb derselben erfolgen kann, als ''Enzyme'' zu bezeichnen."'' (Translation: In order to obviate misunderstandings and avoid cumbersome periphrases, [the author, a university lecturer] suggests designating as "enzymes" the unformed or not organized ferments, whose action can occur without the presence of organisms and outside of the same.)</ref> The word ''enzyme'' was used later to refer to nonliving substances such as [[pepsin]], and the word ''ferment'' was used to refer to chemical activity produced by living organisms.<ref>{{cite book | veditors = Heilbron JL | title = The Oxford Companion to the History of Modern Science | vauthors = Holmes FL | chapter = Enzymes | page = 270 | chapter-url = https://books.google.com/books?id=abqjP-_KfzkC&q=history+of+enzymes+ferment+living+organisms&pg=PA270 | publisher = Oxford University Press | location = Oxford | year = 2003 | isbn = 9780199743766 }}</ref>

[[Image:Eduardbuchner.jpg|alt=Photograph of Eduard Buchner.|thumb|left|Eduard Buchner]]

[[Eduard Buchner]] submitted his first paper on the study of yeast extracts in 1897. In a series of experiments at the [[Humboldt University of Berlin|University of Berlin]], he found that sugar was fermented by yeast extracts even when there were no living yeast cells in the mixture.<ref name="urlEduard Buchner – Biographical">{{cite web | url = http://nobelprize.org/nobel_prizes/chemistry/laureates/1907/buchner-bio.html | title = Eduard Buchner | work = Nobel Laureate Biography | publisher = Nobelprize.org | access-date = 23 February 2015 }}</ref> He named the enzyme that brought about the fermentation of sucrose "[[zymase]]".<ref name="urlEduard Buchner – Nobel Lecture: Cell-Free Fermentation">{{cite web | url = http://nobelprize.org/nobel_prizes/chemistry/laureates/1907/buchner-lecture.html | title = Eduard Buchner – Nobel Lecture: Cell-Free Fermentation | year = 1907 | work = Nobelprize.org | access-date = 23 February 2015 }}</ref> In 1907, he received the [[Nobel Prize in Chemistry]] for "his discovery of cell-free fermentation". Following Buchner's example, enzymes are usually named according to the reaction they carry out: the suffix ''[[-ase]]'' is combined with the name of the [[substrate (biochemistry)|substrate]] (e.g., [[lactase]] is the enzyme that cleaves [[lactose]]) or to the type of reaction (e.g., [[DNA polymerase]] forms DNA polymers).<ref>The naming of enzymes by adding the suffix "-ase" to the substrate on which the enzyme acts, has been traced to French scientist [[Émile Duclaux]] (1840–1904), who intended to honor the discoverers of [[diastase]] – the first enzyme to be isolated – by introducing this practice in his book {{cite book | author = Duclaux E | title = Traité de microbiologie: Diastases, toxines et venins | language = fr | trans-title = Microbiology Treatise: diastases, toxins and venoms | year = 1899 | publisher = Masson and Co | location = Paris, France | url = https://books.google.com/books?id=Kp9EAAAAQAAJ }} See Chapter 1, especially page 9.</ref>

The biochemical identity of enzymes was still unknown in the early 1900s. Many scientists observed that enzymatic activity was associated with proteins, but others (such as Nobel laureate [[Richard Willstätter]]) argued that proteins were merely carriers for the true enzymes and that proteins ''per se'' were incapable of catalysis.<ref name = "Willstätter_1927">{{cite journal| vauthors = Willstätter R | title = Faraday lecture. Problems and methods in enzyme research | journal = Journal of the Chemical Society (Resumed) | date = 1927 | pages = 1359–1381 |  doi = 10.1039/JR9270001359 }} quoted in {{cite journal | vauthors = Blow D | title = So do we understand how enzymes work? | journal = Structure | volume = 8 | issue = 4 | pages = R77–R81 | date = April 2000 | pmid = 10801479 | doi = 10.1016/S0969-2126(00)00125-8 | doi-access = free }}</ref> In 1926, [[James B. Sumner]] showed that the enzyme [[urease]] was a pure protein and crystallized it; he did likewise for the enzyme [[catalase]] in 1937. The conclusion that pure proteins can be enzymes was definitively demonstrated by [[John Howard Northrop]] and [[Wendell Meredith Stanley]], who worked on the digestive enzymes [[pepsin]] (1930), [[trypsin]] and [[chymotrypsin]]. These three scientists were awarded the 1946 Nobel Prize in Chemistry.<ref name="urlThe Nobel Prize in Chemistry 1946">{{cite web | url = http://nobelprize.org/nobel_prizes/chemistry/laureates/1946/ | title = Nobel Prizes and Laureates: The Nobel Prize in Chemistry 1946 | work = Nobelprize.org | access-date = 23 February 2015 }}</ref>

The discovery that enzymes could be crystallized eventually allowed their structures to be solved by [[x-ray crystallography]]. This was first done for [[lysozyme]], an enzyme found in tears, saliva and [[egg white]]s that digests the coating of some bacteria; the structure was solved by a group led by [[David Chilton Phillips]] and published in 1965.<ref>{{cite journal | vauthors = Blake CC, Koenig DF, Mair GA, North AC, Phillips DC, Sarma VR | title = Structure of hen egg-white lysozyme. A three-dimensional Fourier synthesis at 2 Angstrom resolution | journal = Nature | volume = 206 | issue = 4986 | pages = 757–761 | date = May 1965 | pmid = 5891407 | doi = 10.1038/206757a0 | s2cid = 4161467 | bibcode = 1965Natur.206..757B }}</ref> This high-resolution structure of lysozyme marked the beginning of the field of [[structural biology]] and the effort to understand how enzymes work at an atomic level of detail.<ref name="pmid10390620">{{cite journal | vauthors = Johnson LN, Petsko GA | title = David Phillips and the origin of structural enzymology | journal = Trends in Biochemical Sciences | volume = 24 | issue = 7 | pages = 287–289 | date = July 1999 | pmid = 10390620 | doi = 10.1016/S0968-0004(99)01423-1 }}</ref>