| Abstract
| - We have previously cloned and characterized the cDNAs of three isoforms of the 8S globulin ofmungbean, expressed the major 8Sα isoform in Escherichia coli, and purified and successfullycrystallized it (Bernardo, A. E. N.; Garcia, R. N.; Adachi, M.; Angeles, J. G. C.; Kaga, A; Ishimoto,M.; Utsumi, S.; Tecson-Mendoza, E. M. J. Agric. Food Chem. 2004, 52, 2552−2560). Herein, wereport the physicochemical and emulsifying properties of the native 8S and recombinant 8Sα globulinor vicilin. The circular dichroism spectra analysis of the native 8S and recombinant 8Sα globulinsrevealed that the recombinant 8Sα formed a secondary structure close to that of the native 8S. Further,gel filtration analysis showed that 8Sα was able to assemble into trimers. The native 8S andrecombinant 8Sα globulins were soluble at pH 3.4 and at pH 7.4−9.0 at low ionic strength, μ = 0.08.Interestingly, the native 8S was more soluble at pH 7.0 and pH 7.4 than the recombinant 8Sα at μ= 0.08. Both forms were very soluble at pH 3.4−9.0 at high ionic strength, μ = 0.50. The native formexhibited a higher Tm (69.2, 79.5, and 83.8 °C) than the recombinant form (65.6, 71.6, 77.5 °C) at μ= 0.1, 0.2, and 0.5, respectively. The recombinant form was found to have greater surfacehydrophobicity than the native form. There was little difference in the emulsifying ability between thenative 8S and 8Sα at pH 3.4 and pH 7.6. The results indicate that the presence of N-linked glycansis not essential in the assembly and stable conformation of the mungbean vicilin. However, the N-linkedglycans might have contributed to the higher solubility at low ionic strength, greater thermal stability,and decreased surface hydrophobicity of the native vicilin as compared to the recombinant 8Sα. Onthe other hand, the N-linked glycans showed little effect on the emulsifying ability of the protein. Keywords: Functional properties; 8S globulins; mungbean; N-linked glycans; recombinant; physicochemical properties; vicilin; Vigna radiata
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