Rubisco enzyme : It catalyses carboxylation and oxygenation reactions. It is found in the chloroplast (cell organelle).
Chloroplasts in mesophyll cells are granal but chloroplast of bundle sheath cells are arganal. Granal chloroplasts have thylakoids stalked to form grana (as in C3 plants). Agranal chloroplasts are without grana but the thylakoids are found only as stroma lamellae