Editing Galactose (section)

==Structure and isomerism==
Galactose exists in both open-chain and cyclic form. The open-chain form has a [[carbonyl]] at the end of the chain.

Four isomers are cyclic, two of them with a [[pyranose]] (six-membered) ring, two with a [[furanose]] (five-membered) ring. Galactofuranose occurs in bacteria, fungi and protozoa,<ref>{{cite journal | vauthors = Nassau PM, Martin SL, Brown RE, Weston A, Monsey D, McNeil MR, Duncan K | display-authors = 6 | title = Galactofuranose biosynthesis in Escherichia coli K-12: identification and cloning of UDP-galactopyranose mutase | journal = Journal of Bacteriology | volume = 178 | issue = 4 | pages = 1047–52 | date = February 1996 | pmid = 8576037 | pmc = 177764 | url = | doi=10.1128/jb.178.4.1047-1052.1996}}</ref><ref>{{cite journal | vauthors = Tefsen B, Ram AF, van Die I, Routier FH | title = Galactofuranose in eukaryotes: aspects of biosynthesis and functional impact | journal = Glycobiology | volume = 22 | issue = 4 | pages = 456–69 | date = April 2012 | pmid = 21940757 | doi = 10.1093/glycob/cwr144 | doi-access = free }}</ref> and is recognized by a putative chordate immune lectin [[intelectin]] through its exocyclic 1,2-diol. In the cyclic form there are two [[anomer]]s, named alpha and beta, since the transition from the open-chain form to the cyclic form involves the creation of a new [[stereocenter]] at the site of the open-chain carbonyl.<ref name="Ophardt, C. Galactose">{{Cite web |url=http://elmhcx9.elmhurst.edu/~chm/vchembook/543galactose.html |title=Ophardt, C. Galactose |access-date=2015-11-26 |archive-url=https://web.archive.org/web/20060908164848/http://elmhcx9.elmhurst.edu/~chm/vchembook/543galactose.html |archive-date=2006-09-08 |url-status=dead }}</ref>

The [[Infrared spectroscopy|IR spectra]] for galactose shows a broad, strong stretch from roughly wavenumber 2500&nbsp;cm<sup>−1</sup> to wavenumber 3700&nbsp;cm<sup>−1</sup>.<ref name=":1">{{Cite journal|last1=Tunki|first1=Lakshmi|last2=Kulhari|first2=Hitesh|last3=Vadithe|first3=Lakshma Nayak|last4=Kuncha|first4=Madhusudana|last5=Bhargava|first5=Suresh|last6=Pooja|first6=Deep|last7=Sistla|first7=Ramakrishna|date=2019-09-01|title=Modulating the site-specific oral delivery of sorafenib using sugar-grafted nanoparticles for hepatocellular carcinoma treatment|url=https://www.sciencedirect.com/science/article/pii/S0928098719302416|journal=European Journal of Pharmaceutical Sciences|language=en|volume=137|pages=104978|doi=10.1016/j.ejps.2019.104978|pmid=31254645|s2cid=195764874|issn=0928-0987}}</ref>

The [[Proton nuclear magnetic resonance|Proton NMR]] spectra for galactose includes peaks at 4.7 ppm (D<sub>2</sub>O), 4.15 ppm (−CH<sub>2</sub>OH), 3.75, 3.61, 3.48 and 3.20 ppm (−CH<sub>2</sub> of ring), 2.79–1.90 ppm (−OH).<ref name=":1" />

[[File:D-Galactose Haworth.svg|thumb|left|upright=1.5|Cyclic forms of galactose]]
[[File:Galactose Sessel-Konformation.png|none|thumb|390x390px|Chair conformation of D-galactopyranose]]