Analysis of the thermal stability of type II collagen in various solvents used for reversed-phase high performance chromatography.

The thermal stability of type II collagen in various solvents is shown to depend on the ability of the solvent to form hydrogen bonds. Mixtures of water with 1-propanol, 2-propanol, 1,2-propanediol, tetrahydrofuran and acetonitrile effect the stability of the triple helix differently. The temperature of the triple helix coil transition of type II collagen in 50(v/v)% solvent mixture in 0.1% trifluoroacetic acid ranges from 34 degrees C for 1,2-propanediol to 22.5 degrees C for acetonitrile, compared to 38 degrees C in 0.1% trifluoroacetic acid and 41.5 degrees C at neutral pH. There is no correlation between the dielectric constants of the solvents and the decrease in thermal stability, indicating that electrostatic interactions play only a minor role in the stability of the triple helix. Acetonitrile and tetrahydrofuran destabilize the triple helix more than the solvents containing hydroxyl groups. For reversed-phase high performance chromatography 2-propanol is the solvent of choice, but temperature control is very important, because the interaction of the triple helix with the column matrix leads to an additional destabilization of the triple helix beyond the destabilization effect of the solvent. In acetonitrile, a solvent commonly used for reversed-phase high performance chromatography, the triple helix is completely denatured when eluted from a C18 column at room temperature.