So these two H ions and this oxygen basically combine to form a water molecule, and we form a double bond between this nitrogen and this carbon here. So this is carbon one, carbon two, carbon 3456 and seven. And so we form a bond between the nitrogen and carbon number two on this incoming ketone substrate molecules. So this is what we call a shift base. And a shift base is ultimately a connection between the enzyme molecule and this substrate. So this is an enzyme substrate intermediate molecule.