Now, notice this is the same molecule as we have in this particular case. Now, I've labeled this hydrogen as the blue hydrogen. And the reason is because in this reaction, the net changes, the movement, the transfer of the age from carbon one onto the carbon two. 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.