Unusual Behaviour of a Mammalian Collagen in Deuterium Oxide

Abstract

GROSS¹ observed that heating a solution of collagen in phosphate buffer to 37° C resulted in the formation of an opaque gel of collagen fibres. That this occurred at 37° C, but not in the cold, suggests that some unfolding of the collagen molecule is required to form fibres or gels, and that newly synthesized collagen molecules, in vivo, are also not as highly ordered as possible, but are somewhat unfolded in order to form connective tissue fibres. To test this idea in vitro we proposed to conduct the Gross heat gelation in deuterium oxide. Harrington and von Hippel² showed that in the case of ichthyocol collagen in deuterium oxide, the helix→coil transition occurs at a temperature 4° C higher than in water. If heat gelation of collagen in deuterium oxide were to require a higher temperature than in water, the hypothesis would be supported. When we attempted to carry out the experiment, unexpected results were obtained, of which a preliminary report is presented here.