Interaction of α
S1-κ-casein complex with Ca
2+, Ba
2+, Mg
2+ and Sr
2+ was investigated. On the addition of 0 to 11mM of these ions, the sedimentation coefficients of α
S1-κ-casein complex increased gradually with the rise of concentration of the ions. On the addition of more than 11mM of Ca
2+ and Ba
2+, a new peak with a higher sedimentation coefficient (large aggregate) appeared, while such a new peak did not appear on the addition of Mg
2+ and Sr
2+. The amounts of Ca
2+ and Ba
2+ bound to α
S1-κ-casein complex were higher than those of bound Mg
2+ and Sr
2+. An apparant partial specific volume of α
S1-κ-casein complex decreased remarkably on the addition of more than 11 mM of Ca
+2, while it decreased only slightly on the addition of the same concentration of Mg
2+ Stable α
S1-κ-casein micelles were formed by Ca
2+ and Ba
2+, but not by Mg
2+ and Sr
2+. From the above results, it is suggested that the formation of the large aggregate of α
S1-κ-casein complex is essential for the formation of the stable casein micelles.
抄録全体を表示