An isothermal titration calorimetry study of phytate binding to lysozyme

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• 作者：Samuel J. Darby ; Lauren Platts…
• 关键词：Allostery ; Cooperative binding ; ITC ; Phytase ; Digestion
• 刊名：Journal of Thermal Analysis and Calorimetry
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：127
• 期：2
• 页码：1201-1208
• 全文大小：848KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Physical Chemistry; Analytical Chemistry; Polymer Sciences; Inorganic Chemistry; Measurement Science and Instrumentation;
• 出版者：Springer Netherlands
• ISSN：1588-2926
• 卷排序：127

文摘

Isothermal titration calorimetry (ITC) was used to detect phytate binding to the protein lysozyme. This binding interaction was driven by electrostatic interaction between the positively charged protein and negatively charged phytate. When two phytate molecules bind to the protein, the charge on the protein is neutralised and no further binding occurs. The stoichiometry of binding provided evidence of phytate–lysozyme complex formation that was temperature dependent, being most extensive at lower temperatures. The initial stage of phytate binding to lysozyme was less exothermic than later injections and had a stoichiometry of 0.5 at 313 K, which was interpreted as phytate crosslinking two lysozyme molecules with corresponding water displacement. ITC could make a valuable in vitro assay to understanding binding interactions and complex formation that normally occur in the stomach of monogastric animals and the relevance of drinking water temperature on the extent of phytate–protein interaction. Interpretation of ITC data in terms of cooperativity is also discussed.