2025, 5(2): 65-72.
doi: 10.1515/fzm-2025-0007
Objectives Cold-acclimated organisms accumulate low molecular weight organic solutes such as sugar alcohols and soluble sugars. This study aimed to compare the efficacy of five sugar alcohols and 14 soluble sugars in stabilizing proteins under freezing, freeze-drying, and air-drying stresses. Materials and methods Glucose-6-Phosphate Dehydrogenase (G6PD) was used as the model protein. G6PD solutions with or without sugar alcohols and or sugars were subjected to freezing, freeze-drying, and air-drying stresses. The recovery of G6PD activity was measured to evaluate the protective efficacy of these compounds. Results Without stabilizers, freezing G6PD at -20℃ or -80℃ reduced enzyme activity by around 24%, while freeze-drying or air-drying reduced activity by 90%-95%. Among the five sugar alcohols tested, pinitol, quebrachitol and sorbitol stabilized G6PD, whereas mannitol and myo-inositol destabilized it. Among 14 soluble sugars, trehalose and raffinose showed slightly lower enzyme recovery after repeated freeze-thaw cycles at -20℃. Most soluble sugars (except arabinose and xylose) protected G6PD during freeze-drying, with di-, tri-, and oligosaccharides generally outperforming monosaccharides. During air-drying, lactose was ineffective, while arabinose, galactose, and xylose were detrimental. Conclusion The study highlights the diverse mechanisms of sugar alcohols and sugars in protein stabilization under stress, offering insights for formulating stable protein- and cell-based drugs.
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