PURIFICATION OF BETA-LACTOGLOBULIN - ISOLATION OF GENETIC-VARIANTS AND INFLUENCE OF PURIFICATION METHOD ON SECONDARY STRUCTURE

A simple, rapid, and effective method for obtaining large quantities of the pure genetic variants (A or B) of beta-Lactoglobin (beta-Lg) for the study of functional properties is described. The milk proteins from individual cows producing only-beta-Lg A or B are screened using a non-dissociating polyacrylamide gel electrophoresis procedure. Milk is collected from those cows producing the desired variant and beta-Lg is purfied using a trichloroacetic acid precipitation procedure. No further purification or anion exchange chromatography is necessary. The secondary structure, as determined by circular dichroism, is compared for beta-Lg isolated by sodium sulfate precipitation and by trichloroacetic acid precipitation.