Xylulose is a
ketopentose, a
monosaccharide
Monosaccharides (from Greek ''monos'': single, '' sacchar'': sugar), also called simple sugars, are the simplest forms of sugar and the most basic units (monomers) from which all carbohydrates are built.
They are usually colorless, water-solub ...
containing five
carbon atoms, and including a
ketone
In organic chemistry, a ketone is a functional group with the structure R–C(=O)–R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group –C(=O)– (which contains a carbon-oxygen double bo ...
functional group. It has the
chemical formula . In nature, it occurs in both the
L- and
D-
enantiomer
In chemistry, an enantiomer ( /ɪˈnænti.əmər, ɛ-, -oʊ-/ ''ih-NAN-tee-ə-mər''; from Ancient Greek ἐνάντιος ''(enántios)'' 'opposite', and μέρος ''(méros)'' 'part') – also called optical isomer, antipode, or optical ant ...
s. 1-Deoxyxylulose is a precursor to
terpenes via the
DOXP pathway
The non-mevalonate pathway—also appearing as the mevalonate-independent pathway and the 2-''C''-methyl-D-erythritol 4-phosphate/1-deoxy-D-xylulose 5-phosphate (MEP/DOXP) pathway—is an alternative metabolic pathway for the biosynthesis of the i ...
.
Pathology
L-Xylulose accumulates in the
urine in patients with
pentosuria
Pentosuria is a condition where the sugar xylitol, a pentose, presents in the urine in unusually high concentrations. It was characterized as an inborn error of carbohydrate metabolism in 1908. It is associated with a deficiency of L-xylulose re ...
, due to a deficiency in
L-xylulose reductase
Dicarbonyl/L-xylulose reductase, also known as carbonyl reductase II, is an enzyme that in human is encoded by the DCXR gene located on chromosome 17.
Structure
The DCXR gene encodes a membrane protein that is approximately 34 kDa in size an ...
. Since
L-xylulose is a reducing sugar like
D-glucose, pentosuria patients have been wrongly diagnosed in the past to be
diabetic.
References
{{Carbohydrates
Ketopentoses