[Influence of dioxane on the hydration shell of polypeptides].

Our interest in modifying influence of the low-molecular organic compounds on the hydration shell of biopolymers is due to a well-known fact that the former can act as regulators of the enzymatic activity changed the hydration shell of the latter. Dioxane was chosen because of its wide application in non-aqueous biocatalysis. In the present study we investigate the mechanisms of the dioxane influence on water of the first hydration layer of the model polypeptides by FTIR-spectroscopy during simultaneous sorption of water-dioxane vapors into the polypeptide films at low water activity. It was found that modification of the hydration shell of the studied polypeptides was mainly due to the indirect ordering ofpolypeptide secondary structure at penetration of dioxane molecules at these conditions.