Protein phosphorylation is an important post-translational modification that regulates milk protein structure and function.The objective of this study was to analyze the presence of phosphorylated casein.Bovine milk p...Protein phosphorylation is an important post-translational modification that regulates milk protein structure and function.The objective of this study was to analyze the presence of phosphorylated casein.Bovine milk proteins were first separated by SDS polyacrylamide gel electrophoresis.After in gels digestion and extraction,phosphorylated peptides were enriched by titanium dioxide and identified by ultra performance liquid chromatography coupled with nano electrospray ionization tandem mass spectrometry.This method ensured the identification of 20 phosphorylated peptides,including 7 phosphorylated forms of α_s1-casein,8 α_s2-casein,and 5 β-casein.Eight phosphorylated sites derived from 3 α_s1-caseins,3 α_s2-caseins,and 2 β-caseins were also identified,and localized on residues Ser^61,Ser^63 and Ser^130 in α_s1-casein;Thr^145,Ser^146 and Ser^158 in α_s2-casein;and Ser^50 and Thr^56 in β-casein.These findings provide valuable information for investigating casein phosphorylation of the bovine milk.展开更多
基金supported by an earmark fund for the National Key Basic Research Program of China(2011CB100805)
文摘Protein phosphorylation is an important post-translational modification that regulates milk protein structure and function.The objective of this study was to analyze the presence of phosphorylated casein.Bovine milk proteins were first separated by SDS polyacrylamide gel electrophoresis.After in gels digestion and extraction,phosphorylated peptides were enriched by titanium dioxide and identified by ultra performance liquid chromatography coupled with nano electrospray ionization tandem mass spectrometry.This method ensured the identification of 20 phosphorylated peptides,including 7 phosphorylated forms of α_s1-casein,8 α_s2-casein,and 5 β-casein.Eight phosphorylated sites derived from 3 α_s1-caseins,3 α_s2-caseins,and 2 β-caseins were also identified,and localized on residues Ser^61,Ser^63 and Ser^130 in α_s1-casein;Thr^145,Ser^146 and Ser^158 in α_s2-casein;and Ser^50 and Thr^56 in β-casein.These findings provide valuable information for investigating casein phosphorylation of the bovine milk.
