On the other hand, the beta subbunits actually are the ones that will play that catalytic role. They have the ability to actually undergo these three reactions. They're the ones that bind the ATP and orthophosphere reactants. They're the ones that catalyze the synthesis of the ATP and they're the ones that release that ATP molecules once a rotation actually takes place as we'll see in more detail in just a moment. In fact, notice that we have three different confirmations. That is, the beta subunits can actually exist in one of three different states and that's because we have three different reactions that have to be carried out by this alpha three, beta three hexamer.