Characterization of phytase from three ferns with differing arsenic tolerance.
Λέξεις-κλειδιά
Αφηρημένη
Phytase is involved in many physiological activities in plants including phosphorus metabolism and stress response. The effects of arsenic on phytase activities in arsenic-hyperaccumulator Pteris vittata were determined. Two arsenic-sensitive ferns (Pteris ensiformis and Nephrolepis exaltata) were included for comparison purpose. Fern phytase was extracted with Tris-HCl buffer (pH 7.6) followed by ammonium sulfate partial purification to characterize its properties and arsenic stress responses. The phytase showed an optimum pH of 5.0 and temperature of 40 °C except for P. vittata with 40-70 °C. Phytase from P. vittata was the first plant-phytase showing high heat resistance with no loss of activity by heating it at 70 °C, which may have application in feed industry. Phytase activity was inhibited by arsenate but not by arsenite. The fact that P. vittata phytase was the most heat-tolerant (40-70 °C) and had the highest resistance to arsenate among the three ferns suggest that phytase may play a role in arsenic detoxification and arsenic hyperaccumulation in P. vittata.