Isolation of ß-Lactogobulin and -Lactalbumin by Gel Filtration Using Sephacryl S-200 and Purification by Diethylaminoethyl Ion-Exchange Chromatography

¹ Department of Applied Biological Science, Hiroshima University, Higashi-Hiroshima City 724, Japan

ß-Lactoglobulin dimer (408 mg) was easily and gently separated from neutralized acid whey (200 ml) by gel filtration as the fourth peak eluted from Sephacryl S-200. This ß-lactoglobulin was separated into A (63%) and B (37%) variants by DEAE ion-exchange chromatography ants each showed single bands of similar mobility on SDS-PAGE and double bands with like mobilities on SDS-urea-PAGE however, the variants showed different mobilities on native PAGE.

-Lactalbumin (98 mg) was also easily and gently separated by the gel filtration as the fifth peak (134 mg protein). Other proteins recovered in P5 fraction were trace amounts of ß-lactoglobulin monomer and an unidentified albumin (14,000 Da). After purification by Aschaffenburg and Drewry's method, ß-lactoglobulin monomer was absent from -lactalbumin fraction; however, the unidentified albumin remained.

Key Words: ßbeta;-lactoglobulin A • ßbeta;-lactoglobulin B • -lactalbumin • gel filtration

Submitted on July 17, 1989
Accepted on February 13, 1990