Question

Can ribulose biphosphate (RuBP) combine with both carbon dioxide and oxygen gas?

Answer 1

RuBP stands for ribulose bisphosphate, it's a 5 carbon compound involved in the Calvin cycle, which is part of the light-independent reactions of photosynthesis. Atmospheric CO2 is combined with RuBP to form a 6 carbon compound, with the help of an enzyme (biological catalyst) called RuBisCo.The enzyme, Rubisco, not only initiates carbon fixation in the Calvin cycle; it also combines with oxygen to initiate photo-respiration. As its name suggests (rubisco) the enzyme is both a carboxylase and an oxygenase. The active site of rubisco cannot distinguish the two similar substrates: O=C=O and O=O.