Abstract：In this study，the tertiary，secondary structures and disulfide bond changes of bovine lactoferrin (bLF) under 6 differents physico-chemical treatments were investigated by fluorescence，circular dichroism(CD) and UV-Vis absorption.A red shift from 333 to 354 nm in the fluorescence emission maximum (λmax) was observed in the bLF treated by 6 mol·L-1 GdnHCl，8 mol·L-1 Urea and 50 mmol·L-1 DTT simultaneously，meanwhile a large number of exposed hydrophobic groups were detected.However，there was no marked shift in λmax of bLF treated by heating (100 ℃，5 min)，Ultrosonic(450 W，5 s，6 pulses) or β-ME(1%)， of which fluorescence intensity decreased significantly compared with the untreated bLF. The results indicated that the mechanism of changes in tertiary structure of the former three methods were different from the latter three. The detection by CD showed that the α- helix structure vanished completely in the bLF treated by GdnHCl. However，there was no remarkable change in the secondary structure of the bLF treated by the other five methods.In addition，UV-Vis absorption suggested that disulfide bond was seriously destructed in the bLF treated by DTT and Ultrosonict，but GdnHCl，β-ME and heating induced a little damage merely. This study is instructive and meaningful to the further research on relationship between structure and activity of bLF.
Key words：Bovine lactoferrin;Circular dichroism;Spectroscopic analysis;Structure characteristic;Disulfide bond
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