The geometries of the basic dimers of hyaluronan and chondroitin were compared by quantum chemical calculations. As is known the two systems differ in the relative orientation of one hydroxyl group. The basic unit of hyaluronan in its lowest-energy structure is some 20 kJ mol-1 lower in energy than the lowest-energy chondroitin unit. However, the interconversion between the two systems is prevented by a very high energy barrier. The introduction of aqueous medium somewhat changes the relative stabilities of various structures within the hyaluronan sets and chondroitin sets, respectively, but does not change the energy preference of hyaluronan over chondroitin though somewhat diminishes it.
- Axial versus equatorial
- Hyaluronic acid