RuBP carboxylase is a less efficent enzyme for `CO_(2)` fixation in photosynthesis than PEP carboxylase because:

Options

A. RuBP is less predominant than PEP in a mesophyll cell
B. RuBP is a 4-carbon sugar phosphate while PEP is a phosphorylated 3-carbon organic acid.
C. Km value of RuBP carboxylase for `CO_(2)` is higher than that of PEP carboxylase
D. The molecular weight of RuBP carboxylase is larger than that of PEP carboxylase

Answer

C

Explanation

RuBP carboxylase is a very slow enzyme, fixing only three molecules of its substrate every second and hence a large amount of this enzyme is needed by each plant. Typically, RuBP carboxylase accounts for 50% or so of the total protein in a chloroplast.