Studies on κ-Casein of Bovine Milk I : Purity of κ-casein prepared by several different methods (Agricultural Chemistry)

五種類のκ-カゼイン調製法を比較検討した結果, 収量の点では各方法とも酸カゼイン43gより2ないし3gで有意の差は認められなかった。一方, セファデックスゲルろ過とデンプンゲル電気泳動によって純度を比較したところMckejieらのカルシューム・エタノール法とYaguchiらのセファデックス法が好結果を与えた。しかし, 純度の点で問題のあったSwaisgoodらのTCA法, Zittleのの尿素硫酸法でも, 各々セファデックス処理を加えること, 酢酸アンモンによる沈殿形成時の温度条件を厳守することにより高純度のκ-カゼインを調製しうることを認めた。A comparison of five procedures for preparing κ-casein from the acid casein of bovine milk was made based on the criterion of purity using Sephadex gel filtration and starch gel electrophoresis. There were no significant differences in yields among the five procedures, by which two to three grams of κ-casein were obtained from 43 grams of acid casein. But the κ-casein prepared using the calcium ethanol method described by Mckenjie and Wake or by the Sephadex method described by Yaguchi et al. was very pure. It was also shown that it is possible to prepare reasonably pure κ-casein using the trichloroacetic acid method, described by Swaisgood and Brunner, combined with Sephadex treatment, and using the urea sulfuric acid method described by Zittle and Custer when temperature was strictly controlled in the precipitation step of κ-casein by ammonium acetate