Heat-Stable Phytases in Transgenic Wheat (Triticum aestivum L.): Deposition Pattern, Thermostability, and Phytate Hydrolysis
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- 作者：Henrik Brinch-Pedersen ; Frank Hatzack ; Eva Stö ; ger ; Elsa Arcalis ; Katrine Pontopidan ; and Preben B. Holm
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2006
- 出版时间：June 28, 2006
- 年：2006
- 卷：54
- 期：13
- 页码：4624 - 4632
- 全文大小：541K
- 年卷期：v.54,no.13(June 28, 2006)
- ISSN：1520-5118
文摘
The present paper addresses the question of thermotolerance of in planta synthesized heterologousenzymes using phytase as a model. Two individual transgenic wheat materials expressing anAspergillus fumigatus phytase with a low denaturation temperature (62.5 
C) but a high refoldingcapacity, and a rationally designed consensus phytase engineered to a high denaturation temperature(89.3 C), were evaluated. High levels of endosperm specific expression were ensured by the wheathigh molecular weight glutenin 1DX5 promoter. Immunodetection at the light and electron microscopicallevel shows unequivocally that the heterologous phytase is deposited in the vacuole, albeit that thetransformation constructs were designed for secretion to the apoplast. Evaluation of heat stabilityproperties and kinetic properties unraveled that, under these deposition conditions, heat stability basedon high unfolding temperature is superior to high refolding capacity and represents a realistic strategyfor improving phosphate and mineral bioavailability in cereal-based feed and food.Keywords: Phytase; phytate; heat stability; micronutrients; phosphate
C) but a high refoldingcapacity, and a rationally designed consensus phytase engineered to a high denaturation temperature(89.3 C), were evaluated. High levels of endosperm specific expression were ensured by the wheathigh molecular weight glutenin 1DX5 promoter. Immunodetection at the light and electron microscopicallevel shows unequivocally that the heterologous phytase is deposited in the vacuole, albeit that thetransformation constructs were designed for secretion to the apoplast. Evaluation of heat stabilityproperties and kinetic properties unraveled that, under these deposition conditions, heat stability basedon high unfolding temperature is superior to high refolding capacity and represents a realistic strategyfor improving phosphate and mineral bioavailability in cereal-based feed and food.Keywords: Phytase; phytate; heat stability; micronutrients; phosphate