抄録
Pyrenebutyrate-conjugated αs1-casein was prepared and the complex formation between αs1-and κ-casein polymers was investigated by fluorescence polarization. The complex formation was also investigated by a microcalorimetric technique. The positive enthalpy and entropy changes and endothermic nature suggested the hydrophobic interaction between αs1-and κ-casein polymers.
The degree of polarization of κ-casein polymer decreased with the addition of 1-anilino-8-naphthalenesulfonate (ANS), while that of αs1-casein polymer and αs1-κ-casein complex was invariant. Moreover the reaction of κ-casein polymer and ANS was exothermic. These facts suggested that the intermolecular hydrophobic regions in κ-casein polymer were disrupted by the adsorption of ANS. The rotational relaxation time of pyrenebutyrate conjugated complex between cyanoethyl-κ-casein and αs1-casein polymer was smaller than that of cyanoethyl-κ-casein alone. From these results, it was postulated that the dissociation of κ-casein polymer by the complex formation with αs1-casein polymer might be caused by the disruption of the intermolecular hydrophobic bonds in κ-casein polymer.
