CO2RuBisCO

CO2RuBisCO refers to the enzyme **Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO)** in its role as the primary enzyme responsible for fixing carbon dioxide (CO₂) during photosynthesis. RuBisCO is one of the most abundant proteins on Earth, playing a central role in the Calvin cycle, the biochemical pathway that converts CO₂ into organic compounds like glucose. The name "CO2RuBisCO" emphasizes its function in carbon fixation, distinguishing it from its secondary role in photorespiration, where it reacts with oxygen instead of CO₂.

RuBisCO is a large, complex enzyme found in the chloroplasts of plants, algae, and some bacteria. It catalyzes the carboxylation of ribulose-1,5-bisphosphate (RuBP), a five-carbon sugar, combining it with CO₂ to produce two molecules of 3-phosphoglycerate (3-PGA). This reaction is the first step in the synthesis of carbohydrates, which serve as energy storage and structural components in organisms.

Despite its importance, RuBisCO is not highly efficient. It has a low catalytic turnover rate and can also bind oxygen, leading to photorespiration—a process that consumes energy and releases CO₂, reducing photosynthetic efficiency. This dual reactivity is due to the similar concentrations of CO₂ and O₂ in the atmosphere, making RuBisCO’s specificity for CO₂ a challenge for evolutionary optimization.

Researchers have explored genetic and biochemical approaches to improve RuBisCO’s efficiency, such as engineering variants with higher specificity for CO₂ or developing synthetic alternatives. These efforts aim to enhance photosynthetic productivity, particularly in crops, to address food security and climate change concerns. Understanding and modifying RuBisCO remains a key focus in plant biochemistry and synthetic biology.