Xylulose 5-phosphate

D-Xylulose 5-phosphate (D-xylulose-5-P) is an intermediate in the pentose phosphate pathway. It is a ketose sugar formed from ribulose-5-phosphate by ribulose-5-phosphate epimerase. In the non-oxidative branch of the pentose phosphate pathway, xylulose-5-phosphate acts as a donor of two-carbon ketone groups in transketolase reactions.^[2]

Xylulose 5-phosphate

Names
IUPAC name 5-O-Phosphonato-D-xylulose
Systematic IUPAC name d-threo-Pent-2-ulose 5-phosphate[1]
Identifiers
CAS Number	60802-29-1 N
3D model (JSmol)	Interactive image
ChEBI	CHEBI:57737 Y
ChemSpider	20015725 Y
MeSH	xylulose-5-phosphate
PubChem CID	850
CompTox Dashboard (EPA)	DTXSID601314181
InChI InChI=1S/C5H11O8P/c6-1-3(7)5(9)4(8)2-13-14(10,11)12/h4-6,8-9H,1-2H2,(H2,10,11,12)/p-2/t4-,5-/m1/s1 Y Key: FNZLKVNUWIIPSJ-RFZPGFLSSA-L Y
SMILES [O-]P([O-])(=O)OC[C@@H](O)[C@H](O)C(=O)CO
Properties
Chemical formula	C5H11O8P
Molar mass	230.109 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Xylulose-5-phosphate also plays a crucial role in the regulation of glycolysis through its interaction with the bifunctional enzyme PFK2/FBPase2. Specifically, it activates protein phosphatase, which then dephosphorylates PFK2/FBPase2. This inactivates the FBPase2 activity of the bifunctional enzyme and activates its PFK2 activity.^[3] As a result, the production of fructose 2,6-bisphosphate increases, ultimately leading to an upregulation of glycolysis.^[4]

Although previously thought of mainly as an intermediary in the pentose phosphate pathway, recent research reported that the sugar also has a role in gene expression, mainly by promoting the ChREBP transcription factor in the well-fed state.^[5][6] However, more recent study showed that D-glucose-6-phosphate, rather than D-xylulose-5-phosphate, is essential for the activation of ChREBP in response to glucose.^[7]