Phosphoketolase

The enzyme phosphoketolase(EC 4.1.2.9) catalyzes the chemical reactions

D-xylulose 5-phosphate + phosphate ${\displaystyle \rightleftharpoons }$ acetyl phosphate + D-glyceraldehyde 3-phosphate + H₂O (EC 4.1.2.9) ^[1]

D-fructose 6-phosphate + phosphate ${\displaystyle \rightleftharpoons }$ acetyl phosphate + D-erythrose 4-phosphate + H₂O (EC 4.1.2.22)^[2]

D-sedoheptulose 7-phosphate + phosphate ${\displaystyle \rightleftharpoons }$ acetyl phosphate + D-ribose 5-phosphate + H₂O^[3]

Phosphoketolase
Identifiers
EC no.	4.1.2.9
CAS no.	9031-75-8
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Gene Ontology	AmiGO / QuickGO
Search PMC articles PubMed articles NCBI proteins

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.^[4]

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^[5][6][7] as it enables the construction of synthetic pathways that allow complete carbon conservation without the generation of reducing power.^[8]