And that Serene residue actually plays a catalytic role of catalyzing this reaction. So inside the active side of this enzyme, we have a serine that has been modified. We attached a phosphoryl group onto that Serene. So before this reaction actually begins, that serine contains the phosphoryl group. And so when this reaction takes place, that phosphoryl group is transferred from the Serene residue onto carbon six of this glucose, forming that glucose one six bisphosphate intermediate. Now, in the next step of this process, this phosphoryl group is transferred from carbon one onto so from carbon one of the glucose 116 bisphosphate onto that Serene residue.