Xylose
| |||
Names | |||
---|---|---|---|
IUPAC name
d-Xylose
| |||
Other names
(+)-Xylose
Wood sugar | |||
Identifiers | |||
| |||
3D model (
JSmol ) |
|||
ChEMBL | |||
ChemSpider | |||
ECHA InfoCard
|
100.043.072 | ||
EC Number |
| ||
PubChem CID
|
|||
UNII |
| ||
| |||
| |||
Properties[1][2] | |||
C 5H 10O 5 | |||
Molar mass | 150.13 g/mol | ||
Appearance | monoclinic needles or prisms, colourless | ||
Density | 1.525 g/cm3 (20 °C) | ||
Melting point | 144 to 145 °C (291 to 293 °F; 417 to 418 K) | ||
Chiral rotation ([α]D)
|
+22.5° (CHCl 3) | ||
-84.80·10−6 cm3/mol | |||
Hazards | |||
NFPA 704 (fire diamond) | |||
Related compounds | |||
Related aldopentoses
|
Arabinose Ribose Lyxose | ||
Related compounds
|
Xylulose | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|
Xylose (cf.
Structure
The
2(CH(OH))3CHO. The cyclic hemiacetal isomers are more prevalent in solution and are of two types: the pyranoses, which feature six-membered C
5O rings, and the furanoses
4O rings (with a pendant CH
2OH group). Each of these rings is subject to further isomerism, depending on the relative orientation of the anomeric hydroxy group.
The
Occurrence
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 embryos of most edible plants. It was first isolated from wood by Finnish scientist, Koch, in 1881,[3] but first became commercially viable, with a price close to sucrose, in 1930.[4]
Xylose is also the first saccharide added to the
Xylose is also found in some species of Chrysolinina beetles, including Chrysolina coerulans. They have
Applications
Chemicals
The acid-catalysed degradation of hemicellulose gives furfural,[7][8] a precursor to synthetic polymers and to tetrahydrofuran.[9]
Human consumption
Xylose is metabolised by humans, although it is not a major human nutrient and is largely excreted by the kidneys.) which transfer xylose from UDP to a serine in the core protein of proteoglycans.
Xylose contains 2.4 calories per gram[11] (lower than glucose or sucrose, approx. 4 calories per gram).
Animal medicine
In animal medicine,
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.[13]
Hydrogen production
In 2014 a low-temperature 50 °C (122 °F), atmospheric-pressure enzyme-driven process to convert xylose into hydrogen with nearly 100% of the theoretical yield was announced. The process employs 13 enzymes, including a novel polyphosphate xylulokinase (XK).[14][15]
Derivatives
Reduction of xylose by catalytic hydrogenation produces the sugar substitute xylitol.
See also
- Saccharophagus degradans
- Xylonic acid
- Xylose metabolism
References
- ISBN 091191028X, 9995.
- ISBN 0-8493-0462-8..
- ISBN 9780080562643.
- .
- PMID 16675547
- ISBN 9780854046911.
- ; Collected Volumes, vol. 1, p. 280.
- S2CID 104358224.
- ISBN 978-3527306732.
- hdl:2263/27501.
- ^ US US6239274B1, "Method of producing xylose", issued 1999-08-06
- ^ "D-xylose absorption", MedlinePlus, U.S. National Library of Medicine, July 2008, retrieved 2009-09-06
- S2CID 27670020.
- S2CID 1915746. Retrieved 2014-01-22.
- S2CID 1915746.