Phosphoketolase

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In enzymology, a phosphoketolase (EC 4.1.2.9) is an enzyme that catalyzes the chemical reaction

D-xylulose 5-phosphate + phosphate $\rightleftharpoons$ acetyl phosphate + D-glyceraldehyde 3-phosphate + H₂O

Thus, the two substrates of this enzyme are D-xylulose 5-phosphate and phosphate, whereas its 3 products are acetyl phosphate, D-glyceraldehyde 3-phosphate, and H₂O.

This enzyme belongs to the family of lyases, specifically the aldehyde-lyases, which cleave carbon-carbon bonds. The systematic name of this enzyme class is D-xylulose-5-phosphate D-glyceraldehyde-3-phosphate-lyase (adding phosphate; acetyl-phosphate-forming). Other names in common use include D-xylulose-5-phosphate D-glyceraldehyde-3-phosphate-lyase, and (phosphate-acetylating). This enzyme participates in 3 metabolic pathways: pentose phosphate pathway, methane metabolism, and carbon fixation. It employs one cofactor, thiamin diphosphate.

[edit] References

IUBMB entry for 4.1.2.9
BRENDA references for 4.1.2.9 (Recommended.)
PubMed references for 4.1.2.9
PubMed Central references for 4.1.2.9
Google Scholar references for 4.1.2.9
HEATH EC, HURWITZ J, HORECKER BL, GINSBURG A (1958). "Pentose fermentation by Lactobacillus plantarum. I. The cleavage of xylulose 5-phosphate by phosphoketolase". J. Biol. Chem. 231: 1009–29. PMID 13539033.
Schramm M, Klybas V and Racker E (1958). "Phospholytic cleavage of fructose-6-phosphate by fructose-6-phosphate phosphoketolase from Acetobacter xylinum". J. Biol. Chem. 233: 1283–1288.