Data suggest that rubisco (ribulose-1,5-bisphosphate carboxylase) makes up 10% of the
total protein found in spinach leaves. Research elucidating the structure of rubisco
shows that it has four active sites. Why, with four active sites, might there be such a
large concentration of rubisco in plant matter?
Rubisco is a very slow enzyme; what it lacks in speed, it makes up in quantity