concept

rubisco

Facts (11)

Sources

The Ecology of Photosynthetic Pathways | Learn Science at Scitable nature.com Nature 11 facts

measurementRubisco accounts for 25–30% of leaf nitrogen in C3 plants, whereas C4 plants contain three to six times less Rubisco.

procedureThe C4 photosynthetic process involves transferring the 4-carbon acid to bundle sheath cells, where it is decarboxylated to release carbon dioxide next to rubisco.

procedureThe CAM photosynthetic pathway proceeds as follows: (1) stomata open at night to allow carbon dioxide to diffuse into the leaf, (2) carbon dioxide is combined with PEP to form malate, (3) malate is stored in large central vacuoles until daytime, (4) during the day, malate is released from the vacuoles and decarboxylated, and (5) rubisco combines the released carbon dioxide with RuBP in the C3 pathway.

claimThe enzyme ribulose bisphosphate carboxylase/oxygenase (rubisco) is the most common soluble protein in the world and can account for 50% of a leaf's nitrogen content.

formulaIn the C3 photosynthetic pathway, the enzyme ribulose bisphosphate carboxylase/oxygenase (rubisco) catalyzes the reaction: RuBP + CO2 → 2PGA.

claimIn C4 plants, mesophyll cells contain PEP carboxylase and few chloroplasts, while bundle sheath cells, which surround the xylem and phloem, contain rubisco and many chloroplasts.

claimThe physical separation of biochemical activities in C4 plants acts as a carbon dioxide concentrating mechanism for rubisco.

claimPhosphoenolpyruvate (PEP) carboxylase has a higher affinity for carbon dioxide than rubisco and lacks oxygenase activity.

claimC4 plants exhibit no photorespiration in intact leaves, even though their rubisco enzyme retains oxygenase activity.

claimPhotorespiration reduces net photosynthesis by 35–50% depending on environmental conditions, primarily through competition between O2 and CO2 for the active site of rubisco and the release of CO2 in the photorespiratory carbon oxidation cycle.

formulaThe enzyme ribulose bisphosphate carboxylase/oxygenase (rubisco) catalyzes an oxygenation reaction: RuBP + O2 → PGA + PG.