Lyxosis

Structural formula
	Fischer projection , open-chain representation
General
Surname	D - (-) - lyxose, L - (+) - lyxose
other names	(2 S , 3 S , 4 R ) tetrahydroxypentanal; (2 R , 3 R , 4 S ) -tetrahydroxypentanal;
Molecular formula	C 5 H 10 O 5
Brief description	White dust
External identifiers / databases
Wikidata	Q85561302
properties
Molar mass	150.13 g mol −1
Physical state	firmly
Melting point	108-112 ° C
solubility	very soluble in water (586 g / l at 25 ° C, L- Lyxose)
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 .

Lyxose is a monosaccharide with five carbon atoms. This sugar belongs to the group of aldopentoses .

Occurrence

Both D- Lyxosis and L- Lyxosis do not occur naturally in free form, they are also only extremely rarely involved in the structure of cell membranes - as is the case with Mycobacterium phlei / Mycobacterium smegmatis , for example . Whenever “Lyxose” is mentioned in this text or in the scientific literature without any additional name ( prefix ), D- Lyxose is meant.

properties

The two cyclic constitutional isomers lyxofuranose and lyxopyranose are obtained through intramolecular hemiacetal formation . Since another center of asymmetry arises during hemiacetal formation , there are two diastereomers, α- and β-lyxofuranose, and α- and β-lyxopyranose. The α- and β-furanose or α- and β-pyranose pairs are also referred to as anomers .

In aqueous solution, the anomeric lyxofuranoses and lyxopyranoses are in equilibrium with one another via the unstable open-chain aldehyde form. The equilibrium is dominated to 71% by α-lyxopyranose, followed by β-lyxopyranose with 29%. The proportion of both Lyxofuranoses together is <1%. The establishment of equilibrium is called mutarotation .

D -Lyxosis - spellings
Wedge formula	Haworth notation
	α- D -lyxofuranose <1%	β- D -lyxofuranose <1%
	α- D -lyxopyranose 71%	β- D -lyxopyranose 29%

Individual evidence

↑ ^a ^b ^c ^d data sheet L- Lyxose at Sigma-Aldrich , accessed on December 21, 2019 ( PDF ).
↑ Data sheet L-Lyxose, 99% from AlfaAesar, accessed on January 11, 2020 ( PDF )(JavaScript required) .
↑ ^a ^b Data sheet D -Lyxose from Sigma-Aldrich , accessed on December 21, 2019 ( PDF ).
↑ KH Khoo, R. Suzuki, A. Dell, HR Morris, MR McNeil, PJ Brennan, GS Besra: Chemistry of the lyxose-containing mycobacteriophage receptors of Mycobacterium phlei / Mycobacterium smegmatis. In: Biochemistry. Volume 35, Number 36, September 1996, pp. 11812-11819, doi : 10.1021 / bi961055 + , PMID 8794763 .
↑ 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).

Web links

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

[Sigma-L-1] ta sheet L- Lyxose at Sigma-Aldrich , accessed on December 21, 2019 ( PDF ).

[Alfa-2] Data sheet L-Lyxose, 99% from AlfaAesar, accessed on January 11, 2020 ( PDF )(JavaScript required) .

[Sigma-D-3] Data sheet D -Lyxose from Sigma-Aldrich , accessed on December 21, 2019 ( PDF ).

[ACS-4] KH Khoo, R. Suzuki, A. Dell, HR Morris, MR McNeil, PJ Brennan, GS Besra: Chemistry of the lyxose-containing mycobacteriophage receptors of Mycobacterium phlei / Mycobacterium smegmatis. In: Biochemistry. Volume 35, Number 36, September 1996, pp. 11812-11819, doi : 10.1021 / bi961055 + , PMID 8794763 .

[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).