Hydrophobic chromatography of galactosyltransferase

Abstract

O-Glycosidic analogs of N-acetylglucosamine are good substrates for galactosyltransferase, and as the O-substituted group becomes more hydrophobic, the apparent Km decreases as much as 2000-fold. l-leucine, leucine-amide, norleucine, valine, ε{lunate}-amino-n-caproic acid and tyrosine-agaroses all retain galactosyltransferase in the presence of 1.25 m ammonium sulfate. The enzyme is eluted quantitatively with a five- to tenfold purification by a decreasing linear gradient of ammonium sulfate. Galactosyltransferase was not specifically bound on any of a series of ω-aminoalkylagaroses tested. A simple and highly efficient procedure for the isolation of galactosyltransferase from bovine skim milk was developed and consisted of a 40-60% ammonium sulfate precipitation of the enzyme from skim milk followed by chromatography on (1) norleucine-Sepharose, (2) UDP-hexanolamine-Sepharose, and (3) α-lactalbumin-Sepharose. © 1976.