查看“︁木糖”︁的源代码

{{noteTA|G1=生命科学}}
{{Chembox
|   Reference=<ref>''[[Merck Index]]'', 11th Edition, '''9995'''.</ref>
|   Name = <small>D</small>-木糖
|   ImageFileL1 = Xylose.png
|   ImageSizeL1 = 120px
|   ImageNameL1 = D-吡喃木糖
|   ImageFileR1 = Xylofuranose.png
|   ImageSizeR1 = 130px
|   ImageNameR1 = 呋喃木糖
|   ImageFile2 = Xylose linear.png
|   ImageSize2 = 180px
|   ImageName2 = 木糖 链形结构
|   NameEn = Xylose
|   IUPACName = (2''R'',3''S'',4''R'')-2,3,4,5-tetrahydroxypentanal
|   OtherNames = <small>D</small>-(+)-木糖、五碳醛糖
| Section1 = {{Chembox Identifiers
| CASNo = 58-86-6
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo1 = 609-06-3
| CASNo1_Comment =  (<small>L</small>-isomer)
| CASNo1_Ref = {{cascite|correct|ESIS}}
| CASNo2 = 41247-05-6
| CASNo2_Comment =  (racemate)
| CASNo2_Ref = {{cascite|correct|ESIS}}
|  CASOther  =  D-：<span class="reflink plainlinksneverexpand">[http://www.ncbi.nlm.nih.gov/sites/entrez?db=pccompound&cmd=search&term=58-86-6 58-86-6]</span><br />L-：<span class="reflink plainlinksneverexpand">[http://www.ncbi.nlm.nih.gov/sites/entrez?db=pccompound&cmd=search&term=609-06-3 609-06-3]</span><br />DL：<span class="reflink plainlinksneverexpand">[http://www.ncbi.nlm.nih.gov/sites/entrez?db=pccompound&cmd=search&term=41247-05-6 41247-05-6]</span>
|  SMILES  =  C([C@H]([C@@H]([C@H](C=O)O)O)O)O
|  UNII_Ref  = {{fdacite|correct|FDA}}|  UNII  =  A1TA934AKO
|  ChEMBL_Ref  = {{ebicite|changed|EBI}}|  ChEMBL  =  502135
|  PubChem  =  135191
|  ChemSpiderID_Ref  = {{chemspidercite|changed|chemspider}}|  ChemSpiderID  =  119104
|  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
}}
| Section2 = {{Chembox Properties
|   Appearance = 无色或白色单斜针状结晶粉末
|   Formula = C<sub>5</sub>H<sub>10</sub>O<sub>5</sub>
|   Density = 1.525 g/cm<sup>3</sup> ([[攝氏]]20°C)
|   MolarMass = 150.13 
|   MeltingPt = {{convert|144|-|145|°C|°F K}}
|   Solubility = 51.24 g/100g ([[攝氏]]20°C)
  }}
}}

'''木糖'''（[[化学式]]：C<sub>5</sub>H<sub>10</sub>O<sub>5</sub>）是一种[[戊醛糖]]，为白色细针状结晶或结晶性粉末。可溶于水和温热[[乙醇]]，不溶于[[乙醚]]，有[[还原性]]、[[左旋与右旋|右旋光性]]和[[变旋现象]]，<math>\rm \ [\alpha]_D^{20} +18.2^o \sim + 19.4^o</math>。略有特殊气味和爽口甜味，甜味相当于[[蔗糖]]的0.4倍。[[甘油醛|<small>D</small>]]-木糖以[[多醣]]的形式天然存在于植物中，可以从[[黑木耳]]或农产品废弃物（如[[棉桃]]的外皮，[[玉米]]的[[秸秆]]、[[穗轴]]）中提取。

== 制取方法 ==
以[[草木类]]、种子壳、木材等多缩木糖含量高的植物作为原料，与[[硫酸]]或[[盐酸]]进行加水分解，使木材中属[[半纤维素]]的[[木聚糖]]水解成<small>D</small>-木糖，然后用[[酵母]]发酵以除去[[葡萄糖]]，再精制浓缩而成。

== 用途 ==
动物中[[羊]]几乎能完全利用木糖，[[猪]]能利用约70％，用木糖饲养[[大鼠]]则可引起[[白内障]]。人体无法消化和利用木糖，木糖不能为[[消化酶]]分解，而是直接经[[空肠]]粘膜吸收，不在体内代谢，从肾排出。因此木糖被用作无热量的[[甜味剂]]，以满足[[糖尿病]]患者和爱吃甜食却又担心发胖者的需求。医学上的[[D-木糖吸收试验|<small>D</small>-木糖吸收试验]]就是通过测定病人在空腹口服<small>D</small>-木糖5小时后[[尿]]内的木糖排出量而反映出病人的小肠吸收功能。<ref>[http://www.nlm.nih.gov/medlineplus/ency/article/003606.htm D-xylose absorption] {{Wayback|url=http://www.nlm.nih.gov/medlineplus/ency/article/003606.htm |date=20160704213211 }}, MedlinePlus Medical Encyclopedia</ref><ref>{{cite web|url=http://jbk.39.net/keshi/neike/xiaohua/checkup/48f91.html|title=吸收不良综合征应该做哪些检查？|publisher=39健康网|accessdate=2009-05-16|archive-url=https://web.archive.org/web/20100309041625/http://jbk.39.net/keshi/neike/xiaohua/checkup/48f91.html|archive-date=2010-03-09|dead-url=yes}}</ref>

将木糖催化[[氢化]][[还原]]后就得到[[木糖醇]]，木糖醇用作[[甜味剂]]，用途更加广泛。

在动物[[蛋白多糖]]中<small>D</small>-木糖与[[肽|多肽链]]的[[丝氨酸]]和[[苏氨酸]][[残基]]以[[糖苷键]]连接，而成为多糖侧链与[[蛋白质]]的桥接结构（如[[硫酸乙酰肝素]]和[[硫酸软骨素]]）。<ref>{{cite journal en|author=Buskas T, Ingale S, Boons GJ| title=Glycopeptides as versatile tool for glycobiology|journal= Glycobiology | volume=16 | issue = 8 | pages = 113R–136R | year = 2006|doi=10.1093/glycob/cwj125|pmid=16675547}}</ref>

== 參見 ==
* [[低聚木糖]]
== 参考资料 ==
{{reflist}}

{{Carbohydrates}}
[[Category:戊醛糖]]