Reversible changes of canavalin solubility controlled by divalent cation concentration in crude sword bean extract

Abstract

Canavalin is a vicilin-class (7S) storage protein found in sword bean (Canavalia gladiata). Our previous report indicated that canavalin is precipitated by the addition of 20 mM MgCl₂ to crude sword bean extract. Here, we examined the solubility changes induced by the addition of Mg²⁺ and Ca²⁺ at various concentrations. Canavalin tended to be insolubilized at relatively low concentrations of MgCl₂ (< 20 mM) and solubilized at relatively high concentrations (> 20 mM). In addition, canavalin was slightly insolubilized in the presence of NaCl. Overall, the results revealed that solubility changes are reversible and depend on the concentration of divalent cations. Therefore, we suggested a reaction scheme that describes the effects of divalent cations on the solubility of canavalin, which would facilitate the study of its physiological function and the application of canavalin in the food processing industry.

Graphical abstract

The solubility changes of canavalin are reversible and depend on the concentration of divalent cations.

Key words:

• 7S globulin
• divalent cation
• canavalin
• reversible solubility change
• sword bean

Acknowledgments

We would like to thank Editage (www.editage.jp) for English language editing.