title: Purification and conformational changes of bovine PEGylated β-lactoglobulin related to antigenicity.
abstract: β-Lactoglobulin (β-LG) was conjugated with monomethoxy polyethylene glycol-succinimidyl carbonates (mPEG-SC, 20 kDa) to investigate the relationship between the antigenicity and conformational changes of β-LG. The effect of molar ratio of protein to mPEG-SC (1:3-1:6), pH (6-8) and time (4-24h) on the antigenicity of β-LG was investigated. The lowest antigenicity of β-LG was observed at the molar ratio of 1:3, pH 7.0, and reaction time for 8h, which was 70% lower than that of control β-LG. At the optimal modification conditions, it was indicated that two fractions obtained after purification showed the tense and single band on the SDS-PAGE at the position of approximate 78 kDa and 58 kDa, which corresponded to the tri- and di-PEGylated conjugate, respectively. As conjugated number of mPEG-SC with β-LG increased, the quenching of fluorescence and the content of β-strands were increased gradually, which may contribute to the decrease of antigenicity from two aspects.
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
authors.forename: Junzhen
authors.initials: J
authors.lastname: Zhong
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Cai
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
authors.forename: Chengmei
authors.initials: C
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China. Electronic address: liuwei@ncu.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
authors.forename: Yujia
authors.initials: Y
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
authors.forename: Shunjing
authors.initials: S
authors.lastname: Luo
mesh_terms: D000818:Animals; D002417:Cattle; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods*; D007782:Lactoglobulins / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*
chemical_list: D007782:Lactoglobulins; D011092:Polyethylene Glycols
keywords: Antigenicity; Conformation; Polyethylene glycol (PEG); β-Lactoglobulin