ribulose 1,5-bisphosphate carboxylase
Quick Summary
Ribulose 1,5-bisphosphate carboxylase, often abbreviated as RuBisCO, is a crucial enzyme in photosynthesis. It plays a primary role in the Calvin-Benson cycle, a key part of the "dark reactions" where plants convert carbon dioxide into sugars. RuBisCO catalyzes the initial step of carbon fixation, attaching atmospheric carbon dioxide to a five-carbon compound called ribulose 1,5-bisphosphate (RuBP).123
This enzyme is the most abundant protein on Earth, essential for converting inorganic carbon into organic compounds that fuel life. However, RuBisCO also has a catalytic flaw: it can react with oxygen as well as carbon dioxide. This can lead to a process called photorespiration, which reduces photosynthetic efficiency, especially in hot and dry conditions.32
Ask Britannica AI about this topic
Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.
photosynthesisStage 1: Carboxylation…is catalyzed by the enzyme ribulose 1,5-bisphosphate carboxylase (Rubisco), proceeds by the addition of carbon dioxide to the five-carbon compound ribulose 1,5-bisphosphate (RuBP) and the splitting of the resulting six-carbon compound into two molecules of PGA. This reaction occurs three times during each complete turn of the cycle; thus, six…
Read More…is catalyzed by the enzyme ribulose 1,5-bisphosphate carboxylase (Rubisco), proceeds by the addition of carbon dioxide to the five-carbon compound ribulose 1,5-bisphosphate (RuBP) and the splitting of the resulting six-carbon compound into two molecules of PGA. This reaction occurs three times during each complete turn of the cycle; thus, six…
Read More
plantSpecific variations in photosynthesisThe enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes the formation of organic molecules from CO2. As the major enzyme of all photosynthetic cells, Rubisco is the most abundant protein on Earth. There is, however, a major catalytic flaw in the ability of this enzyme to convert CO2 to…
Read MoreThe enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes the formation of organic molecules from CO2. As the major enzyme of all photosynthetic cells, Rubisco is the most abundant protein on Earth. There is, however, a major catalytic flaw in the ability of this enzyme to convert CO2 to…
Read More