And so this is nothing more than an oxidation reduction reaction in which this trio spausia isomerase basically transforms this ketos into an aldos by transferring the eight from carbon one onto this carbon number two. So we see that trio's phosphate, isomerase TPI catalyzes, the conversion of the keto, the DHAP, into the aldos, the gap, via an intramolecular oxidation reduction reaction in which a hydrogen is transferred from carbon one onto carbon two. So this is a keto is because we have the carbon attached onto two carbons here. This is an aldos because we have an H and a carbon atom attached to the carbon of the carbonyl. Now, that's the general idea of what happens, but what exactly happens within the active side of this enzyme? So let's take a look at the following four picture diagrams.