Both mechanisms exhibit the same distance between the proton donor and the glycosidic oxygen, situating the proton donor close enough to the glycosidic oxygen for hydrogen bonding. It is the distance between the nucleophile and the anomeric carbon where the two mechanisms begin to diverge. Because the inversion mechanism must accommodate enough space for the water molecule, the nucleophile is situated further away from the anomeric carbon. In the retention mechanism, this distance is only 5.5 -7 angstroms but increases to 9-10 angstroms in the inversion mechanism. Furthermore, the inversion mechanism was found to proceed through a single displacement mechanism involving an oxocarbenium ion-like transition state. Due to the retention mechanism's proximity between the two carboxyl groups, it goes through a double displacement mechanism that produces a covalent glycosyl-enzyme intermediate.