[1]: 2  It is a colourless anion, a double phosphate ester of the ketopentose (ketone-containing sugar with five carbon atoms) called ribulose.

[4][5] Calvin, who had been away from the lab at the time of discovery and was not listed as a co-author, controversially removed the full molecule name from the title of the initial paper, identifying it solely as "ribulose".

[4][6] At the time, the molecule was known as ribulose diphosphate (RDP or RuDP) but the prefix di- was changed to bis- to emphasize the nonadjacency of the two phosphate groups.

The functionality of rubisco activase involves removing RuBP and other inhibitory bonded molecules to re-enable carbamylation on the active site.

[1]: 103  Similarly, photorespiration is limited in CAM photosynthesis due to kinetic delays in enzyme activation, again stemming from the ratio of carbon dioxide to oxygen.