Leaf Functional Anatomy in Relation to Photosynthesis1

Rubisco is a large enzyme with a molecular mass of approximately 550 kD. The maximum rate of CO2 fixation (i.e. ribulose-1,5-bisphosphate [RuBP] carboxylation) at CO2 saturation is only 15 to 30 mol CO2 mol−1 Rubisco protein s−1 at 25°C. Affinity to CO2 is also low, and the K m, K c, at 25°C