Ketosis

Comparison of a ketose (left, example D- fructose) with an aldose (right, example D- glucose). In ketoses, the carbon atom is part of the carbonyl function of a keto group in position 2 , see left.

Ketoses (polyhydroxyketones), derived from the word ketone , are carbohydrates from the group of monosaccharides . They contain an eponymous keto group and thus differ from the aldoses that carry an aldehyde group (see illustration). An important representative of the ketoses is D - fructose . The prefix “Keto-” indicates the affiliation to the ketoses: One speaks, for example, of ketohexoses or ketopentoses .

Ketoses can be isomerized to aldoses by the Lobry-de-Bruyn-Alberda-van-Ekenstein rearrangement .

"Pedigree" of the D -Ketoses. By adding (HC – OH) groups, the basic structure is lengthened so that further sugars can be derived (from trioses with three carbon atoms to hexoses with six carbon atoms. This formal derivation of the pentoses and hexoses from the one COH2 group shorter in each case leads to an additional center of asymmetry .).
( 1 ) dihydroxyacetone ;
( 2 ) D - erythrulose ;
( 3a ) D - ribulose ; ( 3b ) D - xylulose ;
( 4a ) D - psicose ; ( 4b ) D - fructose ; ( 4c ) D - sorbose ; ( 4d ) D - Tagatose

literature

D. Voet, J. Voet: Biochemistry , 4th ed., Wiley, Weinheim 2011. ISBN 978-0-47057095-1 .
Hans-Dieter Belitz , Werner Grosch, Peter Schieberle : Food chemistry . 4th edition, Springer, Berlin 2009. ISBN 978-3-540-69935-4 .

Individual evidence

↑ Adalbert Wollrab: Organic chemistry: an introduction for teacher training and minor students . 4th edition. Springer Spectrum, Berlin [a. a.] 2014, ISBN 978-3-642-45143-0 , p. 788-789 .

[1] Adalbert Wollrab: Organic chemistry: an introduction for teacher training and minor students . 4th edition. Springer Spectrum, Berlin [a. a.] 2014, ISBN 978-3-642-45143-0 , p. 788-789 .