Which enzyme is the most abundant protein on Earth and catalyzes both carboxylation and oxygenation of RuBP?
Answer and explanation
Correct answer: D. RuBisCO
- Step 1: RuBisCO makes up up to 50% of soluble leaf protein in C3 chloroplasts. Step 2. It fixes atmospheric CO2 into RuBP during photosynthesis, but also binds O2 to initiate photorespiration. Answer: RuBisCO (Ribulose-1,5-bisphosphate carboxylase-oxygenase). Why not the others: PEP carboxylase lacks oxygenase activity; DNA polymerase replicates genomes; Carbonic anhydrase interconverts CO2 and bicarbonate.
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