How many molecules of rubp are oxygenated for each molecule of co2 that is released by photorespiration?

Photorespiration is a process where the enzyme RuBisCO generates RuBP. It is also known as oxidative photosynthetic carbon cycle. This is a process where addition of carbon dioxide takes place in the RuBP.
In this process "two" molecules of RuBP are oxygenated for each molecule of CO2 that is released by photosynthesis.
 

Answer) by studying proton collisions hope this : )