The Method of Aschaffenburg and Drewry for the Crystallization of β-Lactoglobulin and α-Lactalbumin. 1. Electrophoresis of Fractions and the Calcium2+/Ethylenebis (Oxyethylenenitrilo) Tetraacetic Acid Shift of α-Lactalbumin

β -Lactoglobulin and α -Lactalbumin were isolated and crystallized by the classical method of Aschaffenburg and Drewry, and the purity of the crystals was assessed by native PAGE and SDS-PAGE. Although β -lactoglobulin was free of contaminants, α -lactalbumin was still contaminated after five recrystallization steps. Yields of crystals in this study were lower than reported by Aschaffenburg and Drewry. Further, it was observed that α -lactalbumin undergoes a Ca 2+ /Ca 2+ -free, dependent electrophoretic shift characteristic of many calcium-binding proteins.