Purification and IgE-binding properties of soybean β-conglycinin subunits

• Published in: Process biochemistry (1991) 2012-12, Vol.47 (12), p.2531-2537
• Main Authors: Zheng, Shugui, Tian, He, Ma, Na, Qin, Guixin, Sun, Zewei, Yu, Chunyan
• Format: Article
• Language: English
• Subjects: affinity chromatography; allergenicity; Basophil histamine release test; basophils; beta-conglycinin; dose response; food allergies; histamine; IgE immunoblotting; immunoblotting; immunoglobulin E; ion exchange; patients; Purification; soybeans; β-Conglycinin subunits
• ISSN: 1359-5113; 1873-3298
• DOI: 10.1016/j.procbio.2012.07.003

► We developed a new method to purify β-conglycinin subunits. ► We examined allergenic activity of purified subunits. ► Efficient purification of highly purified β-conglycinin subunits was achieved by our method. ► Purified β-conglycinin subunits retained allergenic activity. ► Purified β-conglycinin subunits are promising diagnosis tools for soybean-related allergy. The purpose of this study was to purify soybean β-conglycinin subunits and analyze their IgE-binding properties with IgE immunoblotting and their response in a basophil histamine release test. The method presented in this paper offers an effective procedure to purify β-conglycinin subunits with higher yield and purity compared with previous methods by using a combination of ion exchange and metal chelate affinity chromatography. Beginning with a column load of 600mg β-conglycinin, the new method yielded 100.4mg of protein containing 96.7% α subunit, 97.0mg of protein containing 91.6% α′ subunit and 89.4mg of protein containing 96.1% β subunit. All of the purified subunits of β-conglycinin reacted with IgE from sera of soybean-allergic patients and induced dose-dependent histamine release from basophils from these patients, suggesting that purified α, α′, and β subunits of β-conglycinin retained allergenic activity and could be used for in vitro and in vivo diagnosis of soybean-induced food allergy.