A new site-specific monoPEGylated β-lactoglobulin at the N-terminal: Effect of different molecular weights of mPEG on its conformation and antigenicity. (1st May 2021)

• Record Type: Journal Article
• Authors: Luo, Shunjing; Ji, Li; Zhou, Lei; Chen, Tingting; Zhong, Junzhen; Liu, Wei; Liu, Chengmei
• Is Part Of: Food chemistry. Volume 343(2021)
• Publication Date: 2021-05-01
• Subjects: β-lactoglobulin -- Site specific PEGylation -- Antigenicity -- Conformation -- Mechanism; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2020.128402
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Site-specific PEGylation at the N-terminal was firstly used to modify β-Lg. The antigenicity of β-Lg decreased after PEGylation at the N-terminal. The conformation of β-Lg after PEGylation at the N-terminal slightly changed. The steric hindrance effect of PEG was the main reason for the antigenicity decline. Abstract: A new method was investigated to decline the antigenicity of β-Lactoglobulin (β-LG) by site specifically conjugating β-LG at the N-terminus with 5 kDa and 10 kDa monomethoxy polyethylene glycol propyl aldehyde (mPEG-ALD). The optimal reaction conditions were molar ratio of 1:10 (β-LG:mPEG-ALD), reaction time for 16 h, and pH 5.0, and the content of mono-PEGylated β-LG was 51.3%. The results showed that mono-PEGylated β-LG with molecular mass of 23.2 kDa and 28.5 kDa. The peptide fragments of mPEG5kDa -ALD-β-LG produced the same sequence pattern of β-LG except for the absence of one peptides f(1–14), indicating that α-amino group at the N-terminal was selectively modified. Furthermore, the conformation of modified β-LG underwent into slight change. The antigenicity of mPEG5kDa -ALD-β-LG and mPEG10kDa -ALD-β-LG decreased from 144.4 μg/mL to 66.7 and 39.0 μg/mL respectively. It was speculated that the steric hindrance effect of PEG was the main reason for the decline of antigenicity of β-LG.