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首页> 外文期刊>Biotechnology Progress >Polyethylene Glycol-Based Low Generation Dendrimers Functionalized with β-Cyclodextrin as Cryo- and Dehydro-Protectant of Catalase Formulations
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Polyethylene Glycol-Based Low Generation Dendrimers Functionalized with β-Cyclodextrin as Cryo- and Dehydro-Protectant of Catalase Formulations

机译：β-环糊精作为过氧化氢酶制剂的低温和脱水保护剂功能化的基于乙二醇的低代树状聚合物

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摘要

Polyethylene glycol (PEG)-based low generation dendrimers are analyzed as single excipient or combined with trehalose in relation to their structure and efficiency as enzyme stabilizers during freeze-thawing, freeze-drying, and thermal treatment. A novel functional dendrimer (DG_o-CD) based on the known PEG's ability as cryo-protector and β-CD as supramolecular stabilizing agent is presented. During freeze-thawing, PEG and β-CD failed to prevent catalase denaturation, while dendrimers, and especially DG_o-CD, offered the better protection to the enzyme. During freeze-drying, trehalose was the best protective additive but DG"-CD provided also an adequate catalase stability showing a synergistic behavior in comparison to the activities recovered employing PEG or β-CD as unique additives. Although all the studied dendrimers improved the enzyme remaining activity during thermal treatment of freeze-dried formulations, the presence of amorphous trehalose was critical to enhance enzyme stability. The crystallinity of the protective matrix, either of PEG derivatives or of trehalose, negatively affected catalase stability in the freeze-dried systems. When humidified at 52% of relative humidity, the dendrimers delayed trehalose crystallization in the combined matrices, allowing extending the protection at those conditions in which normally trehalose fails. The results show how a relatively simple covalent combination of a polymer such as PEG with β-CD could significantly affect the properties of the individual components. Also, the results provide further insights about the role played by polymer-enzyme supramolecular interactions (host-guest crosslink, hydrogen bonding, and hydrophobic interactions) on enzyme stability in dehydrated models, being the effect on the stabilization also influenced by the physical state of the matrix.
机译：基于聚乙二醇（PEG）的低代树状聚合物被分析为单一赋形剂或与海藻糖结合使用，它们在冷冻解冻，冷冻干燥和热处理过程中作为酶稳定剂的结构和效率均得到改善。基于已知的PEG作为冷冻保护剂和β-CD作为超分子稳定剂的能力，提出了一种新颖的功能性树状聚合物（DG_o-CD）。在冻融过程中，PEG和β-CD不能阻止过氧化氢酶变性，而树枝状聚合物，尤其是DG_o-CD则为酶提供了更好的保护。在冷冻干燥过程中，海藻糖是最好的保护性添加剂，但是与使用PEG或β-CD作为独特添加剂回收的活性相比，DG“ -CD还提供了足够的过氧化氢酶稳定性，表现出协同行为。尽管所有研究的树枝状聚合物均改善了酶在冷冻干燥制剂的热处理过程中，如果要保持其剩余活性，无定形海藻糖的存在对于增强酶的稳定性至关重要;无论是PEG衍生物还是海藻糖，保护性基质的结晶度都会对过氧化氢酶在冷冻干燥系统中的稳定性产生负面影响。在相对湿度为52％的条件下，树枝状聚合物在组合基质中延迟了海藻糖的结晶，从而在通常海藻糖失效的条件下扩展了保护作用，结果表明，聚合物（例如PEG）与β-CD的相对简单的共价组合可能会严重影响各个组件的属性。此外，结果证明进一步了解在脱水模型中聚合物-酶超分子相互作用（主体-客体交联，氢键和疏水性相互作用）对酶稳定性的作用，即对稳定性的影响还受基质物理状态的影响。

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