Sugarcane is a monocotyledonous plant. It has developed an additional C4 cycle also.
Carboxylation in sugarcane : (a) Three molecules of RuBP (Ribulose 1-5 biphosphate) reacts with three molecules of carbon dioxide to produce short lived six-carbon intermediates. This process is called carboxylation and involve the enzyme RuBP carboxylase (or Rubisco).
(b) The 6 carbon intermediate are immediately broken down into 6 molecules of 3 phosphoglyceric and (3PGA) a 3 carbon compound. Rubisco is a large protein molecule.
(c) It comprises 16% of the chloroplast protein and is the most important protein on earth