Crystallization of Goat p - Lactoglobulin

as 'goat lactoglobulin' gave a single peak on electrophoresis at pH 8.0 in barbiturate buffer, but three boundaries separated at pH 7-0 and at least two at pH 4-2-6-0 after 2 hr. at 4-5 v/cm., I= 01. The two main components had their isoelectric points at pH 5-2 and 5-9 respectively in sodium acetate buffer, I= 0-1. 'Goat lactoglobulin' thus behaved in much the same way as crystalline bovine ,B-lactoglobulin, which also gives a single peak on electrophoresis at pH 8 but forms two or more boundaries at pH's 4-8 and 6-2 (Li, 1946). According to Polis, Schmukler, Custer & McMeekin (1950), crystalline bovine P-lactoglobulin shows multiple peaks at pH values acid to its isoelectric point but below pH 3-0 becomes once more a single peak. In the present study goat lactoglobulin was crystallized from ammonium sulphate, and its electrophoretic behaviour was investigated at pH values ranging from pH 4-1 to 8-0. The threeand four-times recrystallized material appeared to be homogeneous on electrophoresis at pH 4-1 and 5-6-8-6, forming single symmetrical boundaries in runs lasting up to seven hours at about 5 v/cm. However, fairly concentrated solutions (above 1 %), analysed at pH 4-6 and 5-1 in sodium acetate buffer, I = 0-1, produced markedly asymmetrical boundaries in the descending limb. The isoelectric point, sedimentation constant and molecular weight ofthe crystalline goat f-lactoglobulin were determined and some of its properties compared with those of crystalline bovine P-lactoglobulin.