$RuBisCo$ is an enzyme that acts both as a carboxylase and oxygenase. Why do you think $RuBisCo$ carries out more carboxylation in $C_{4}$ plants?

(N/A) The enzyme $RuBisCo$ is absent from the mesophyll cells of $C_{4}$ plants. It is present in the bundle-sheath cells surrounding the vascular bundles.
In $C_{4}$ plants,the Calvin cycle occurs in the bundle-sheath cells.
The primary $CO_{2}$ acceptor in the mesophyll cells is phosphoenol pyruvate $(PEP)$,a three-carbon compound.
It is converted into the four-carbon compound oxaloacetic acid $(OAA)$.
$OAA$ is further converted into malic acid or aspartic acid.
These acids are transported to the bundle-sheath cells,where they undergo decarboxylation,releasing $CO_{2}$.
This high concentration of $CO_{2}$ around $RuBisCo$ ensures that it functions primarily as a carboxylase rather than an oxygenase,thereby minimizing photorespiration.