Phosphoketolase Explained

The enzyme phosphoketolase catalyzes the chemical reactions

D-xylulose 5-phosphate + phosphate

\rightleftharpoons

acetyl phosphate + D-glyceraldehyde 3-phosphate + H2O [1]

D-fructose 6-phosphate + phosphate

\rightleftharpoons

acetyl phosphate + D-erythrose 4-phosphate + H2O (EC 4.1.2.22)

D-sedoheptulose 7-phosphate + phosphate

\rightleftharpoons

acetyl phosphate + D-ribose 5-phosphate + H2O[2]

Phosphoketolase is considered a promiscuous enzyme because it was demonstrated to use 3 different sugar phosphates as substrates. In a recent genetic study, more than 150 putative phosphoketolase genes exhibiting varying catalytic properties were found in 650 analyzed bacterial genomes.[3]

This enzyme belongs to the family of lyases, specifically the aldehyde-lyases, which cleave carbon-carbon bonds. It participates in 3 metabolic pathways: pentose phosphate pathway, methane metabolism, and carbon fixation. It employs one cofactor, thiamin diphosphate. Phosphoketolase was previously used for biotechnological purposes[4] [5] [6] as it enables the construction of synthetic pathways that allow complete carbon conservation without the generation of reducing power.[7]

References

Notes and References

  1. Glenn. Katie. Smith. Kerry S.. 2015-01-20. Allosteric Regulation of Lactobacillus plantarum Xylulose 5-Phosphate/Fructose 6-Phosphate Phosphoketolase (Xfp). Journal of Bacteriology. 197. 7. 1157–1163. 10.1128/jb.02380-14. 25605308. 0021-9193. 4352667.
  2. Krüsemann. Jan L.. Lindner. Steffen N.. Dempfle. Marian. Widmer. Julian. Arrivault. Stephanie. Debacker. Marine. He. Hai. Kubis. Armin. Chayot. Romain. 2018. Artificial pathway emergence in central metabolism from three recursive phosphoketolase reactions. The FEBS Journal. 285. 23. 4367–4377. 10.1111/febs.14682. 30347514. 1742-4658. free.
  3. Sánchez. Borja. Zúñiga. Manuel. González-Candelas. Fernando. de los Reyes-Gavilán. Clara G.. Margolles. Abelardo. 2010. Bacterial and Eukaryotic Phosphoketolases: Phylogeny, Distribution and Evolution. Journal of Molecular Microbiology and Biotechnology. 18. 1. 37–51. 10.1159/000274310. 20068356 . 1464-1801.
  4. Sonderegger. M.. Schumperli. M.. Sauer. U.. 2004-05-01. Metabolic Engineering of a Phosphoketolase Pathway for Pentose Catabolism in Saccharomyces cerevisiae. Applied and Environmental Microbiology. 70. 5. 2892–2897. 10.1128/aem.70.5.2892-2897.2004. 15128548. 0099-2240. 404438. 2004ApEnM..70.2892S .
  5. Anfelt. Josefine. Kaczmarzyk. Danuta. Shabestary. Kiyan. Renberg. Björn. Rockberg. Johan. Nielsen. Jens. Uhlén. Mathias. Hudson. Elton P.. 2015-10-16. Genetic and nutrient modulation of acetyl-CoA levels in Synechocystis for n-butanol production. Microbial Cell Factories. 14. 1. 167. 10.1186/s12934-015-0355-9. 26474754. 1475-2859. 4609045 . free .
  6. Meadows. Adam L.. Hawkins. Kristy M.. Tsegaye. Yoseph. Antipov. Eugene. Kim. Youngnyun. Raetz. Lauren. Dahl. Robert H.. Tai. Anna. Mahatdejkul-Meadows. Tina. September 2016. Rewriting yeast central carbon metabolism for industrial isoprenoid production. Nature. 537. 7622. 694–697. 10.1038/nature19769. 27654918. 2016Natur.537..694M . 0028-0836.
  7. Bogorad. Igor W.. Lin. Tzu-Shyang. Liao. James C.. 2013-09-29. Synthetic non-oxidative glycolysis enables complete carbon conservation. Nature. 502. 7473. 693–697. 10.1038/nature12575. 24077099. 2013Natur.502..693B . 0028-0836.