Abstract
The denaturation of γ globulin of rice embryo by heating was investigated. The viscosity of γ globulin from rice embryo increased markedly by heating the solution at 80°C for 30min. By heating at 100°C for 30min, gelation was observed. Accompanying with the increase in the viscosity, the detectable sulfhydryl groups of γ globulin increased markedly. The process apparently exhibited two steps. In comparison with heat denaturation, the effect of urea at room temperature was found to be milder and the conformation change appeared to be reversible.
Calcium ions stimulated heat denaturation and gelation of γ globulin solution. By heat-treatment at 70°C for 30min with calcium ion, the viscosity and sulfhydryl groups of γ globulin rapidly increased. At 80°C with calcium ion, the change of the exposed sulfhydryl groups appeared within 3min, and the protein partially precipitated.
These facts suggest that the heat denaturation was more drastic and irreversible, and the structural change of the protein should involve the unfolding of the peptide chains as well as the destruction of the subunit dissociation.
