LAUSR

BACKGROUND To clarify the role of extension region on the structure-functional relationship of α-subunit of β-conglycinin, α-subunit and its segment of the core region (αc-subunit) were expressed via E. coli system. Their physicochemical properties were compared at acid, neutral, or alkaline circumstances (pH = 4.0, 7.0, and 8.0), and high or low ionic strength (μ = 0.05 and 0.5), respectively. RESULTS Results showed that the extension region contributed to increasing thermal stability, especially at low ionic strength in acidic and neutral conditions. Extension region stabilized α-subunit with high solubility, low turbidity, and small particle size in neutral and alkaline conditions, while these impacts were suppressed at high ionic strength and acidic conditions. Surface hydrophobicity of α-subunit decreased in acidic and alkaline conditions without being interfered with by ionic strength. CONCLUSION It can be concluded that the extension region played a different role in different pH and ionic strength conditions. These factors should be specified carefully and speculated individually to explore more detailed and profound nature of β-conglycinin at the sub-molecular level. The results could benefit a better understanding of the relationship between domain structure and functions of soybean protein. This article is protected by copyright. All rights reserved.