Comparison of thermal stability of ovotransferrin and lactoferrin

OVT and LF were heated at different temperatures of 50 ~ 90 ℃,and changes of their secondary structures,spatial conformation,and solubility were analyzed by circular dichroism( CD),UV absorbance,surface hydrophobicity,and turbidity / solubility tests,respectively. Protein aggregation was assessed by SDS- PAGE.Results showed that no change was observed for physicochemical properties of OVT and LF at 50 ~ 60 ℃.Significant increase of UV absorbance was observed for both LF and OVT at 70 ℃; further increase was observed for LF but not for OVT at 80 ~90 ℃. Significant increase of surface hydrophobicity index was observed for LF and OVT at 70~90 ℃.The surface hydrophobicity index of LF was higher than that of OVT,while the extents of increase were higher for OVT than LF. Decreased percentages of α- helix and increased percentages of β- sheet and random coil were observed for both LF and OVT at 70~90 ℃,but the extents of change were higher for OVT than LF.The band densities and solubility of OVT and LF were decreased at 70~90 ℃,but the extents of decrease were higher for OVT than LF at the same temperatures. In conclusion,changes were observed of structures and functional characteristic for OVT and LF after heating treatment,while the extents of change were higher for OVT than LF.