https://wiki.tiffa.net/w/index.php?action=history&feed=atom&title=Maltose%2FenMaltose/en - Revision history2026-05-23T23:45:22ZRevision history for this page on the wikiMediaWiki 1.43.0https://wiki.tiffa.net/w/index.php?title=Maltose/en&diff=141934&oldid=prevFuzzyBot: Updating to match new version of source page2024-04-21T11:03:19Z<p>Updating to match new version of source page</p>
<p><b>New page</b></p><div><languages /><br />
{{chembox<br />
| Verifiedfields = changed<br />
| Watchedfields = removed<br />
| verifiedrevid = 47716923<br />
| ImageFile = Maltose2.svg<br />
| ImageSize = <br />
| ImageName = α-Maltose<br />
| ImageCaption = α-Maltose<br />
| ImageFile1 = Maltose structure.svg<br />
| ImageSize1 = <br />
| ImageName1 = β-Maltose<br />
| ImageCaption1 = β-Maltose<br />
| IUPACName = 4-''O''-α-<small>D</small>-Glucopyranosyl-<small>D</small>-glucose<br />
| OtherNames = <br />
| SystematicName = (3''R'',4''R'',5''S'',6''R'')-6-(hydroxymethyl)-5-{{(}}[(2''R'',3''R'',4''S'',5''S'',6''R'')-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy}oxane-2,3,4-triol<br />
| Section1 = {{Chembox Identifiers<br />
| ChEBI_Ref = {{ebicite|correct|EBI}}<br />
| ChEBI = 17306<br />
| SMILES = O([C@H]1[C@H](O)[C@@H](O)C(O)O[C@@H]1CO)[C@H]2O[C@@H]([C@@H](O)[C@H](O)[C@H]2O)CO<br />
| UNII_Ref = {{fdacite|correct|FDA}}<br />
| UNII = 66Y63L379N<br />
| KEGG = D00044<br />
| ChEMBL_Ref = {{ebicite|changed|EBI}}<br />
| ChEMBL = 1234209<br />
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}<br />
| StdInChI = 1S/C12H22O11/c13-1-3-5(15)6(16)9(19)12(22-3)23-10-4(2-14)21-11(20)8(18)7(10)17/h3-20H,1-2H2/t3-,4-,5-,6+,7-,8-,9-,10-,11?,12-/m1/s1<br />
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}<br />
| StdInChIKey = GUBGYTABKSRVRQ-PICCSMPSSA-N<br />
| ChemSpiderID1_Ref = {{chemspidercite|correct|chemspider}}<br />
| ChemSpiderID1 = 6019<br />
| ChemSpiderID1_Comment = β-maltose<br />
| InChI = 1S/C12H22O11/c13-1-3-5(15)6(16)9(19)12(22-3)23-10-4(2-14)21-11(20)8(18)7(10)17/h3-20H,1-2H2/t3-,4-,5-,6+,7-,8-,9-,10-,11?,12-/m1/s1<br />
| InChIKey1 = GUBGYTABKSRVRQ-PICCSMPSSA-N<br />
| CASNo = 69-79-4<br />
| CASNo_Ref = {{cascite|correct|CAS}}<br />
| CASNoOther =<br />
| EC_number = 200-716-5<br />
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}<br />
| ChemSpiderID = 388469<br />
| ChemSpiderID_Comment = α-maltose<br />
| PubChem = 6255<br />
}}<br />
| Section2 = {{Chembox Properties<br />
| Properties_ref = <br />
| C=12 | H=22 | O=11<br />
| Appearance = White powder or crystals<br />
| Density = 1.54 g/cm<sup>3</sup><br />
| MeltingPtC = 160 to 165<br />
| MeltingPt_notes = (anhydrous)<br />102–103&nbsp;°C (monohydrate)<br />
| Solubility = 1.080 g/mL (20&nbsp;°C)<br />
| SpecRotation = +140.7° (H<sub>2</sub>O, ''c'' = 10)<br />
}}<br />
| Section7 = {{Chembox Hazards<br />
| ExternalSDS = [https://www.merckmillipore.com/INTERSHOP/web/WFS/Merck-GB-Site/en_US/-/GBP/ProcessMSDS-Start?PlainSKU=MDA_CHEM-105912&ReferrerURL=https%3A%2F%2Fwww.google.co.uk%2F&Origin=SERP&bd=1 External MSDS]<br />
| AutoignitionPt =<br />
}}<br />
| Section8 = {{Chembox Related<br />
| OtherFunction = [[Sucrose]]<br />[[Lactose]]<br />[[Trehalose]]<br />[[Cellobiose]]<br />
}}<br />
}}<br />
[[Image:Amylase reaction.png|thumb|right|260px|Amylase reaction consisting of hydrolyzing amylose, producing maltose]]<br />
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'''Maltose''' ({{IPAc-en|ˈ|m|ɔː|l|t|oʊ|s}} or {{IPAc-en|ˈ|m|ɔː|l|t|oʊ|z}}), also known as '''maltobiose''' or '''malt sugar''', is a [[disaccharide]] formed from two units of [[glucose]] joined with an α(1→4) [[glycosidic bond|bond]]. In the [[isomer]] [[isomaltose]], the two glucose molecules are joined with an α(1→6) bond. Maltose is the two-unit member of the [[amylose]] [[homologous series]], the key structural motif of [[starch]]. When [[beta-amylase]] breaks down starch, it removes two glucose units at a time, producing maltose. An example of this reaction is found in [[germination|germinating]] seeds, which is why it was named after [[malt]]. Unlike [[sucrose]], it is a [[reducing sugar]].<br />
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== History ==<br />
Maltose was discovered by [[Augustin-Pierre Dubrunfaut]], although this discovery was not widely accepted until it was confirmed in 1872 by Irish chemist and brewer [[Cornelius O'Sullivan]]. Its name comes from [[malt]], combined with the suffix '[[-ose]]' which is used in names of sugars.<br />
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== Structure and nomenclature ==<br />
Carbohydrates are generally divided into [[monosaccharide]]s, [[oligosaccharide]]s, and [[polysaccharide]]s depending on the number of sugar subunits. Maltose, with two sugar units, is a disaccharide, which falls under oligosaccharides. Glucose is a [[hexose]]: a monosaccharide containing six carbon atoms. The two glucose units are in the [[pyranose]] form and are joined by an [[glycosidic bond|O-glycosidic bond]], with the first carbon (C<sub>1</sub>) of the first [[glucose]] linked to the fourth carbon (C<sub>4</sub>) of the second [[glucose]], indicated as (1→4). The link is characterized as α because the glycosidic bond to the anomeric carbon (C<sub>1</sub>) is in the opposite plane from the {{chem|C|H|2|O|H}} [[substituent]] in the same ring (C<sub>6</sub> of the first glucose). If the glycosidic bond to the anomeric carbon (C<sub>1</sub>) were in the same plane as the {{chem|C|H|2|O|H}} substituent, it would be classified as a '''β(1→4)''' bond, and the resulting molecule would be [[cellobiose]]. The anomeric carbon (C<sub>1</sub>) of the second glucose molecule, which is not involved in a glycosidic bond, could be either an α- or β-anomer depending on the bond direction of the attached hydroxyl group relative to the {{chem|C|H|2|O|H}} substituent of the same ring, resulting in either α-maltose or β-maltose.<br />
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An [[isomer]] of maltose is [[isomaltose]]. This is similar to maltose but instead of a bond in the α(1→4) position, it is in the α(1→6) position, the same bond that is found at the branch points of [[glycogen]] and [[amylopectin]].<br />
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== Properties ==<br />
Like glucose, maltose is a [[reducing sugar]], because the ring of one of the two glucose units can open to present a free [[aldehyde]] group; the other one cannot because of the nature of the glycosidic bond. Maltose can be broken down to glucose by the [[maltase]] enzyme, which catalyses the hydrolysis of the glycosidic bond.<br />
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Maltose in aqueous solution exhibits [[mutarotation]], because the α and β isomers that are formed by the different conformations of the anomeric carbon have different [[specific rotation]]s, and in aqueous solutions, these two forms are in equilibrium. Maltose can easily be detected by the Woehlk test or Fearon's test on methylamine.<br />
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It has a sweet taste, but is only about 30–60% as sweet as sugar, depending on the concentration.<br />
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== Sources and absorption ==<br />
[[Image:Maltose syrup.jpg|thumb|right|Maltose syrup]]<br />
Maltose is a [[malt]] component, a substance obtained when the grain is softened in water and germinates. It is also present in highly variable quantities in partially hydrolyzed starch products like [[maltodextrin]], [[corn syrup]] and acid-thinned starch.<br />
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Outside of plants, maltose is also (likely) found in [[sugarbag]].<br />
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In humans, maltose is broken down by various maltase enzymes, providing two glucose molecules that can be [[Glucose metabolism|further processed]]: either broken down to provide energy, or stored as glycogen. The lack of the [[sucrase-isomaltase]] enzyme in humans causes [[sucrose intolerance]], but complete maltose intolerance is extremely rare because there are four different maltase enzymes.<br />
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==External links==<br />
*{{Commons category-inline}}<br />
*[https://web.archive.org/web/20051124215824/http://www.elmhurst.edu/~chm/vchembook/546maltose.html Maltose], Elmhurst College Virtual Chembook.<br />
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{{Carbohydrates}}<br />
{{Sugar}}<br />
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{{二次利用|date=17 June 2023}}<br />
[[Category:Disaccharides]]<br />
[[Category:Starch]]<br />
[[Category:Sugars]]<br />
[[Category:Malt]]</div>FuzzyBot