Ribose-5-phosphate isomerase（RPIA) is a member of the ribose 5-phosphate isomerase family. RPIA is an enzyme which catalyzes the conversion between ribose-5-phosphate（R5P) and ribulose-5-phosphate（Ru5P). RPI occurs as 2 separate proteins forms， termed RPIA and RPIB. RPIA has a vital role in the metabolism of plants and animals， as it is involved in the Calvin cycle which takes place in plants， and the pentose phosphate pathway which occurs in plants as well as animals.
