Ribulose bisphosphate

Ribulose 1,5-bisphosphate

Names
IUPAC name 1,5-Di-O-phosphono-D-ribulose
Other names Ribulose 1,5-diphosphate
Identifiers
CAS Number	14689-84-0 N
3D model (JSmol)	Interactive image
ChEBI	CHEBI:16710 Y
ChemSpider	110238 Y
InChI InChI=1S/C5H12O11P2/c6-3(1-15-17(9,10)11)5(8)4(7)2-16-18(12,13)14/h3,5-6,8H,1-2H2,(H2,9,10,11)(H2,12,13,14)/t3-,5-/m1/s1 Y Key: YAHZABJORDUQGO-NQXXGFSBSA-N Y
SMILES O=P(O)(OCC(=O)[C@H](O)[C@H](O)COP(=O)(O)O)O
Properties
Chemical formula	C5H12O11P2
Molar mass	310.09 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Ribulose 1,5-bisphosphate (RuBP) is an organic substance that is involved in photosynthesis. It is a colourless anion, a double phosphate ester of the ketopentose (ketone-containing sugar with five carbon atoms) called ribulose. Salts of RuBP can be isolated, but its crucial biological function happens in solution. To simplify the presentation, the image in the above table depicts the acid form of this anion.

The enzyme ribulose bisphosphate carboxylase oxygenase (RuBisCO) catalyzes the reaction between RuBP and carbon dioxide. The product is the highly unstable six-carbon intermediate known as 3-keto-2-carboxyarabinitol 1,5-bisphosphate. This six-carbon intermediate decays virtually instantaneously into two molecules of 3-phosphoglycerate (3-PGA) (see figure). RuBisCO also catalyzes RuBP with oxygen (O
₂) in a process called photorespiration, a process that is more prevalent at high temperatures. During photorespiration RuBP combines with O
₂ to become 3-PGA + phosphoglycolic acid. In the Calvin cycle, RuBP is a product of the phosphorylation of ribulose-5-phosphate by ATP.