Isolation and characterization of rat alpha-lactalbumin: a glycoprotein.
alpha-Lactalbumin was purified to homogeneity from rat milk. Rat alpha-lactalbumin, in contrast to other alpha-lactalbumins, is a glycoprotein and exhibits an abnormally high molecular weight when obtained by gel filtration or electrophoresis in sodium dodecyl sulfate. The molecular weight by sedimentation equilibrium is 15 400 +/- 5% and of the reduced and alkylated protein is 16 000 when determined by thin-layer chromatography in 6 M guanidine hydrochloride. At least, three major charge forms, all containing carbohydrate and active in the lactose synthetase reaction were demonstrated. The amino acid composition reveals a high proline content which is reflected in a low alpha-helical content.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002241:Carbohydrates / Q000032:analysis; D005260:Female; D005700:Galactosyltransferases / Q000032:analysis; D006023:Glycoproteins / Q000302:isolation & purification; D007768:Lactalbumin / Q000302:isolation & purification; D008892:Milk / Q000032:analysis / Q000201:enzymology; D008970:Molecular Weight; D011247:Pregnancy; D011487:Protein Conformation; D051381:Rats
D000596:Amino Acids; D002241:Carbohydrates; D006023:Glycoproteins; D007768:Lactalbumin; D005700:Galactosyltransferases