Arabinose

Structural formula
	Fischer projection , open-chain representation
General
Surname	Arabinose
other names	(2 S , 3 R , 4 R ) -2,3,4,5-tetrahydroxypentanal; (2 R , 3 S , 4 S ) -2,3,4,5-tetrahydroxypentanal; Pectinosis; Gum sugar; Aloin sugar;
Molecular formula	C 5 H 10 O 5
Brief description	colorless solid
External identifiers / databases
EC number	205-699-8
ECHA InfoCard	100.005.182
PubChem	854
ChemSpider	831
Wikidata	Q71240623
properties
Molar mass	150.13 g mol −1
Physical state	firmly
density	1.6 g cm −3
Melting point	160 ° C [ L - (+) - arabinose]; 159-160 ° C [ D - (-) - arabinose];
solubility	59.4 g / 100 g water at 10 ° C
safety instructions
GHS labeling of hazardous substances	no GHS pictograms
	no GHS pictograms
H and P phrases	H: no H-phrases
	P: no P-phrases
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Arabinose is a naturally occurring simple sugar ( monosaccharide ) that consists of five carbon atoms ( pentose ). Arabinose is sometimes referred to as pectinose , gum sugar or aloin sugar .

Constitution and stereochemistry

The open-chain arabinose is diastereomeric to the three other aldopentoses ribose , xylose and lyxose . As a chiral compound, it consists of the two enantiomers D - (-) - arabinose and L - (+) - arabinose.

The two cyclic constitutional isomers arabinofuranose and arabinopyranose are obtained through intramolecular hemiacetal formation . Since a further center of asymmetry arises during hemiacetal formation , two diastereomers each result, α- and β-arabinofuranose, and α- and β-arabinopyranose. The α- and β-furanose or α- and β-pyranose pairs are also referred to as anomers .

D -Arabinose - spellings
Wedge formula	Haworth notation
	α- D -arabinofuranose	β- D -arabinofuranose
	α- D -arabinopyranose	β- D -arabinopyranose

Each ring shape and each stereoisomer has its own CAS number:

	open- chain	Furanosis		Pyranosis
	open- chain	α	β	α	β
D -arabinosis	10323-20-3	37388-49-1	25545-03-3	608-45-7	6748-95-4
L -arabinosis	5328-37-0	38029-69-5	20074-49-1	7296-55-1	7296-56-2

properties

In aqueous solution, the anomeric arabinofuranoses and arabinopyranoses are in equilibrium with one another via the unstable open-chain aldehyde form. The equilibrium is dominated to 61% by α-arabinopyranose, followed by β-arabinopyranose with 35%. The two arabinofuranoses only play a minor role with 2% each. The establishment of equilibrium is called mutarotation .

Arabinose can not be fermented by ordinary yeast . In 2005, researchers at the Goethe University in Frankfurt am Main succeeded in modifying yeast cultures so that they can also ferment arabinose and xylose to produce ethanol .

Occurrence

The L -form occurs more frequently in food, mostly as a component in polysaccharide chains in the plant kingdom. Like other sugars, it has a sweet taste. The D form was as part of a polysaccharide in tuberculosis - bacilli detected.

Dismantling

The breakdown of L -arabinose in E. coli is controlled by the ara operon . Is L -arabinose present in the cell, which is transcription of a promoter activated and the synthesized mRNA derived from the gene araA apparent, may, after translation in the L -arabinose isomerase to be converted. The L -arabinose isomerase converts L -arabinose into L - ribulose .

Web links

Commons : Arabinose - collection of images, videos and audio files

Individual evidence

↑ Data sheet arabinose (PDF) from Carl Roth , accessed on March 23, 2007.
↑ Data sheet D-arabinose at Sciencelab ( Memento from March 4, 2016 in the Internet Archive ).
↑ ^a ^b ^c Entry on arabinose. In: Römpp Online . Georg Thieme Verlag, accessed on February 20, 2019.
↑ ^a ^b Data sheet D - (-) - Arabinose from AlfaAesar, accessed on February 20, 2019 ( PDF )(JavaScript required) .
↑ Eberhard Breitmeier, Günther Jung: Organic chemistry . Basics, substance classes, reactions, concepts, molecular structure. 5th edition. Georg Thieme Verlag, Stuttgart 2005, ISBN 3-13-541505-8 , p. 851 ( limited preview in Google Book search).
↑ Scientists develop a new type of yeast through "controlled evolution" Genetic engineering yeast turns plant waste into biofuel. scinexx | The knowledge magazine, accessed on January 24, 2020 .
↑ L-arabinose | GoldBio. Retrieved March 5, 2020 .
↑ James W. Patrick, Nancy Lee: Purification and Properties of an I-Arabinose Isomerase from Escherichia coli . In: Journal of Biological Chemistry . tape 243 , no. 16 , 25 August 1968, ISSN 0021-9258 , p. 4312-4318 , PMID 4878429 ( jbc.org [accessed March 5, 2020]).

[Roth-1] Data sheet arabinose (PDF) from Carl Roth , accessed on March 23, 2007.

[2] Data sheet D-arabinose at Sciencelab ( Memento from March 4, 2016 in the Internet Archive ).

[Römpp-3] Entry on arabinose. In: Römpp Online . Georg Thieme Verlag, accessed on February 20, 2019.

[Alfa-4] Data sheet D - (-) - Arabinose from AlfaAesar, accessed on February 20, 2019 ( PDF )(JavaScript required) .

[Breitmeier-5] Eberhard Breitmeier, Günther Jung: Organic chemistry . Basics, substance classes, reactions, concepts, molecular structure. 5th edition. Georg Thieme Verlag, Stuttgart 2005, ISBN 3-13-541505-8 , p. 851 ( limited preview in Google Book search).

[6] Scientists develop a new type of yeast through "controlled evolution" Genetic engineering yeast turns plant waste into biofuel. scinexx | The knowledge magazine, accessed on January 24, 2020 .

[7] L-arabinose | GoldBio. Retrieved March 5, 2020 .

[8] James W. Patrick, Nancy Lee: Purification and Properties of an I-Arabinose Isomerase from Escherichia coli . In: Journal of Biological Chemistry . tape 243 , no. 16 , 25 August 1968, ISSN 0021-9258 , p. 4312-4318 , PMID 4878429 ( jbc.org [accessed March 5, 2020]).