This tutorial will show you some of the key structures of rubisco, the most abundant enzyme on the planet. Rubisco is responsible for carbon fixation by all photosynthetic organisms.

Notice that this structure file shows Rubisco as a homo-octamer, meaning eight identical subunits clustered together. Crystal structures such as this may or may not reflect the state in nature. I am not sure if Rubisco is an octamer inside chloroplasts.

Zoom in to see several copies of the substrate ribulose 1,5-bisphosphate. If every rubisco subunit binds one ribulose substrate, how many identical copies of rubisco are in this structure?

Let's get rid of all but one rubisco monomer and look more closely at its structure. The yellow amino acid is lysine #201, the 201^st amino acid in rubisco. Lysine 201 will flash purple and yellow a couple times.

Now investigate rubisco when it has been activated by rubisco activase.