Ribose 5-phosphate isomerase, type A (IPR004788)

Short name: Ribose5P_isomerase_typA

Family relationships


Ribose 5-phosphate isomerase, also known as phosphoriboisomerase, catalyses the reversible conversion of D-ribose 5-phosphate to D-ribulose 5-phosphate, the first step in the non-oxidative branch of the pentose phosphate pathway [PMID: 12517338]. This reaction enables ribose to be synthesized from sugars, as well as the recycling of sugars during the degradation of nucleotides. There are two unrelated types of ribose 5-phosphate isomerases: type A (RpiA) is the most common and is found in most organisms, while type B (RpiB) is restricted to specific eukaryotic and prokaryotic species. Escherichia coli produces both RpiA and RpiB (also known as AlsB), although RpiA accounts for 99% of total RPI enzymes [PMID: 12211039].

This entry represents type A (RpiA) enzymes found in eukaryotes (plants, Metazoa and fungi), bacteria and archaea.

GO terms

Biological Process

GO:0009052 pentose-phosphate shunt, non-oxidative branch

Molecular Function

GO:0004751 ribose-5-phosphate isomerase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.