An enzyme responsible for virtually all photosynthetic CO2 fixation. It is located in the stromal surface of the thylakoid membranes of chloroplasts (q.v.). RuBisCO is probably the most abundant protein in the biosphere, since it makes up about 40% of the protein in green leaves. RuBisCO catalyzes the reaction:
d-ribulose-1,5-bisphosphate + CO2→ 2,3 phospho-d-glycerate.
The enzyme consists of eight large subunits (Mr 56,000 each) and eight small subunits (Mr 14,000 each). See cyanelles, Cyanobacteria, rbc genes.
Subjects: Genetics and Genomics.