Give information about $RuBisCO$.

(N/A) $RuBisCO$ is the most abundant enzyme in the world.
- Characteristic: It is characterized by the fact that its active site can bind to both $CO_{2}$ and $O_{2}$ - hence the name (Ribulose bisphosphate carboxylase-oxygenase).
- Speciality: $RuBisCO$ has a much greater affinity for $CO_{2}$ than for $O_{2}$.
- Mechanism: It is the relative concentration of $O_{2}$ and $CO_{2}$ that determines which of the two will bind to the enzyme.
- Impact: In $C_{3}$ plants,some $O_{2}$ does bind to $RuBisCO$ instead of $CO_{2}$,leading to photorespiration,which decreases the efficiency of $CO_{2}$ fixation.