Xylose: Difference between revisions

{{Short description|Sugar}}

{{redirect|Wood sugar|the related sugar alcohol|Xylitol}}

| Verifiedfields = changed

| verifiedrevid =

| Name = -Xylose

| ImageFileL1 = Xylose.

| ImageNameL1 = D-Xylopyranose

| ImageFileR1 = Xylofuranose.png

| ImageSizeR1 = 130px

| ImageNameR1 = Xylofuranose

| ImageFile2 = D-Xylose.svg

| ImageSize2 = 180px

| ImageName2 = Xylose chair

| = Xylose

| ImageSize3 = 180px

| ImageName3 = Xylose linear

| = Xylose

| OtherNames = (+)-Xylose<br/>Wood sugar

|Section1={{Chembox Identifiers

| CASNo = 58-86-6

| CASNo_Ref = {{cascite|correct|CAS}}

| CASNo1 = 609-06-3

| CASNo1_Comment = ({{sm|l}}-isomer)

| CASNo1_Ref = {{cascite|correct|ESIS}}

| CASNo2 = 41247-05-6

| CASNo2_Comment = (racemate)

| CASNo2_Ref = {{cascite|correct|ESIS}}

| EC_number = 200-400-7 <!-- 210-174-1 for L-isomer, 255-277-2 for racemate -->

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = A1TA934AKO

| UNII1_Ref = {{fdacite|correct|FDA}}

| UNII1 = A4JW0V2MYA

| UNII1_Comment = ({{sm|l}}-isomer)

| ChEMBL_Ref = {{ebicite|changed|EBI}}

| ChEMBL = 502135

| PubChem = 135191

| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}

| ChemSpiderID = 119104

| SMILES = C1[C@H]([C@@H]([C@H](C(O1)O)O)O)O

| InChI = 1/C5H10O5/c6-2-1-10-5(9)4(8)3(2)7/h2-9H,1H2/t2-,3+,4-,5?/m1/s1

| InChIKey = SRBFZHDQGSBBOR-IOVATXLUBL

| StdInChI_Ref = {{stdinchicite|changed|chemspider}}

| StdInChI = 1S/C5H10O5/c6-2-1-10-5(9)4(8)3(2)7/h2-9H,1H2/t2-,3+,4-,5?/m1/s1

| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}

| StdInChIKey = SRBFZHDQGSBBOR-IOVATXLUSA-N

|={{Chembox

| Properties_ref =<ref>{{Merck11th|9995}}.</ref><ref>{{RubberBible62nd|page=C-574}}.</ref>

| Appearance = monoclinic needles or prisms, colourless

| Formula = {{chem|C|5|H|10|O|5}}

| Density = 1.525 g/cm³ (20&nbsp;°C)

| MolarMass = 150.13 g/mol

| MeltingPtC = 144 to 145

| MeltingPt_notes =

| SpecRotation = +22.5° ({{chem|C|H|Cl|3}})

| MagSus = -84.80·10⁻⁶ cm³/mol

|={{Chembox

| NFPA-H = 1

| NFPA-F = 1

| NFPA-R = 0

| FlashPt =

}}

|Section8={{Chembox Related

| OtherFunction = [[Arabinose]]<br/>[[Ribose]]<br/>[[Lyxose]]

| OtherFunction_label = [[Pentose|aldopentoses]]

| OtherCompounds = [[Xylulose]]

'''Xylose''' (cf. |, , "wood") is a sugar first isolated from wood, and named for it. Xylose is classified as a [[monosaccharide]] of the [[aldopentose]] type, which means that it contains five [[carbon]] atoms and includes an [[aldehyde]] [[functional group]]. It is [[hemicellulose]], one of the main constituents of [[biomass]]. Like most sugars, it can adopt several structures depending on conditions. With its free group, it is a [[reducing sugar]].

The [[acyclic]] form of xylose has [[chemical formula]] HOCH2((OH)). The cyclic [[hemiacetal]] isomers are more prevalent in solution and are of two types: the , which feature six-membered C5O rings, and the , which feature five-membered C4O rings (with a pendant CH2OH group). Each of these rings subject to further isomerism, depending on the relative orientation of the anomeric hydroxy group.

The [[dextrorotation and levorotation|dextrorotary]] form, {{sm|d}}-xylose, is the one that usually occurs [[endogeny (biology)|endogenously]] in [[life|living things]]. A levorotary form, {{sm|l}}-xylose, can be [[organic synthesis|synthesized]].

Xylose is the main building block for the [[hemicellulose]] [[xylan]], which comprises about 30% of some plants (birch for example), far less in others (spruce and pine have about 9% xylan). Xylose is otherwise pervasive, being found in the [[embryo]]s of most edible plants. It was first isolated from wood by Finnish scientist, Koch, in 1881,<ref>{{cite book |editor-first=C.S. |editor-last=Hudson |editor2-first=S.M. |editor2-last=Cantor |title=Advances in Carbohydrate Chemistry |publisher=Elsevier |date=2014 |orig-date=1950 |volume=5 |isbn=9780080562643 |pages=278 |url=https://books.google.com/books?id=rUapoxXf-v4C}}</ref> but first became commercially viable, with a price close to [[sucrose]], in 1930.<ref>{{cite journal |first1=Mabel M. |last1=Miller |first2=Howard B. |last2=Lewis |title=Pentose Metabolism: I. The Rate of Absorption of d-Xylose and the Formation of Glycogen in the Organism of the White Rat after Oral Administration of d-Xylose |journal=Journal of Biological Chemistry |volume=98 |issue=1 |pages=133–140 |date=1932 |doi=10.1016/S0021-9258(18)76145-0 |doi-access=free }}</ref>

Xylose is also the first saccharide added to the [[serine]] or [[threonine]] in the [[proteoglycan]] type [[O-glycosylation]], and, so, it is the first saccharide in biosynthetic pathways of most anionic [[polysaccharide]]s such as [[heparan sulfate]] and [[chondroitin sulfate]].<ref>{{citation | last1 = Buskas | first2 = Sampat | last2 = Ingale | first3 = Geert-Jan | last3 = Boons | title = Glycopeptides as versatile tool for glycobiology | journal = Glycobiology | volume = 16 | issue = 8 | pages = 113R–36R | year = 2006 | doi = 10.1093/glycob/cwj125 | pmid = 16675547 | first1 = Therese}}</ref>

Xylose is also found in some species of Chrysolinina beetles, including ''Chrysolina coerulans''. They have [[cardiac glycosides]] (including xylose) in their defensive glands.<ref>{{cite book |first=E. David |last=Morgan |title=Biosynthesis in Insects |year=2004 |chapter=§ 7.3.1 Sterols in Insects |chapter-url={{google books|AbXid2E-17YC |page=112 |plainurl=yes}} |page=112 |publisher=Royal Society of Chemistry |isbn=9780854046911}}</ref>

== Applications ==

=== Chemicals ===

The acid-catalysed degradation of hemicellulose gives [[furfural]],<ref>{{OrgSynth | title = Furfural | volume = 1 | pages = 49 | year = 1921 | collvol = 1 | collvolpages = 280 |first= Roger |last=Adams |first2=V. |last2=Voorhees | prep = cv1p0280 |doi=10.15227/orgsyn.001.0049}}</ref><ref>{{cite journal|last=Gómez Millán |first=Gerardo|author2=Hellsten, Sanna|author3=King, Alistair W.T. |author4=Pokki, Juha-Pekka|author5=Llorca, Jordi|author6=Sixta, Herbert |title=A comparative study of water-immiscible organic solvents in the production of furfural from xylose and birch hydrolysate |journal=Journal of Industrial and Engineering Chemistry |date=25 April 2019|volume=72 |pages=354–363|doi=10.1016/j.jiec.2018.12.037|hdl=10138/307298|s2cid=104358224 |hdl-access=free}}</ref> a precursor to synthetic polymers and to [[tetrahydrofuran]].<ref>{{Ullmann|doi=10.1002/14356007.a12_119.pub2|chapter=Furfural and Derivatives|year=2007|last1=Hoydonckx|first1=H. E.|last2=Van Rhijn|first2=W. M.|last3=Van Rhijn|first3=W.|last4=De Vos|first4=D. E.|last5=Jacobs|first5=P. A.|isbn=978-3527306732}}

</ref>

=== Human consumption ===

Xylose is metabolised by humans, although it is not a major human nutrient and is largely excreted by the kidneys.<ref>{{cite thesis |url=https://repository.up.ac.za/handle/2263/27501 |title=Physiological and microbiological studies of nectar xylose metabolism in the Namaqua rock mouse, ''Aethomys namaquensis'' (A. Smith, 1834) |last=Johnson |first=S.A. |date=2007-08-24 |type=PhD |hdl=2263/27501}}</ref> Humans can obtain xylose only from their diet. An [[oxidoreductase]] pathway is present in [[eukaryotic microorganism]]s. Humans have enzymes called [[protein xylosyltransferase]]s ([[XYLT1]], [[XYLT2]]) which transfer xylose from UDP to a serine in the core protein of proteoglycans.

Xylose contains 2.4 calories per gram<ref>{{Cite patent|title=Method of producing xylose|gdate=1999-08-06 |number=US6239274B1 |country=US |url=https://patents.google.com/patent/US6239274B1/en}}</ref> (lower than glucose or sucrose, approx. 4 calories per gram).

=== Animal medicine ===

In animal medicine, [[D-Xylose absorption test|xylose is used to test]] for [[malabsorption]] by administration in water to the patient after [[fasting]]. If xylose is detected in [[blood]] and/or [[urine]] within the next few hours, it has been absorbed by the intestines.<ref>{{citation | url = https://www.nlm.nih.gov/medlineplus/ency/article/003606.htm | title = D-xylose absorption | work = MedlinePlus | publisher = U.S. National Library of Medicine | date = July 2008 | access-date = 2009-09-06}}</ref>

High xylose intake on the order of approximately 100 g/kg of animal body weight is relatively well tolerated in pigs, and in a similar manner to results from human studies, a portion of the xylose intake is passed out in urine undigested.<ref>{{cite journal |vauthors=Schutte JB, de Jong J, Polziehn R, Verstegen MW |title=Nutritional implications of D-xylose in pigs |journal=Br J Nutr |volume=66 |issue=1 |pages=83–93 |date=July 1991 |pmid=1931909 |doi=10.1079/bjn19910012 |s2cid=27670020 |doi-access=free }}</ref>

=== Derivatives ===

[[Organic redox reaction|Reduction]] of xylose by catalytic [[hydrogenation]] produces the [[sugar substitute]] [[xylitol]].

* ''[[Saccharophagus degradans]]''

* [[ ]]

[[Category:Pyranoses]]

[[Category:Furanoses]]