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Updated: Aug 29, 2026

Formulations for Freeze-drying of Bacteria and Their Influence on Cell Survival
Published on: August 3, 2013
Protection of protein secondary structure by saccharides of different molecular weights during freeze-drying
Ken-ichi Izutsu1, Nobuo Aoyagi, Shigeo Kojima
1National Institute of Health Sciences, Tokyo, Japan. izutsu@nihs.go.jp
Abstract:
The protective effects of saccharides with various molecular weights (glucose, maltose, maltotriose, maltotetraose, maltopentaose, maltoheptaose, dextran 1060, dextran 4900, and dextran 10200) against lyophilization-induced structural perturbation of model proteins (BSA, ovalbumin) were studied. Fourier transform infrared (FT-IR) analysis of the proteins in initial solutions and freeze-dried solids indicated that maltose conferred the greatest protection against secondary structure change. The structure-stabilizing effect of maltooligosaccharides decreased in increasing the number of saccharide units. Larger molecules of dextran also showed a smaller structure-stabilizing effect. Increasing the effective saccharide molecular size by a borate-saccharide complexation reduced the protein structure-stabilizing effect of all of the saccharides except glucose. The results indicate that the larger saccharide molecules, and/or the complex formation with borate ion, reduce the free and accessible hydroxyl groups to interact with and stabilize the protein structure by a water-substitution mechanism.
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