The complete primary structure of alpha-lactalbumin isolated from pig (Sus scrofa) milk.
The complete amino-acid sequence of pig alpha-lactalbumin has been determined. It was obtained by microsequencing of the native protein and the peptides derived after tryptic or cyanogen bromide cleavage. The tryptic peptides were separated by a rapid microbore HPLC method. Pig alpha-lactalbumin is 122 amino acids long and differs from the bovine homologue by 26 exchanged residues. Of the two prolines present in bovine alpha-lactalbumin, one has been deleted in the pig structure. All previously sequenced alpha-lactalbumins have shown glutamic acid at position 49, which is known to be the active site in the homologous lysozyme c structure. This residue is replaced by phenylalanine in pig alpha-lactalbumin indicating that the pig protein is the first alpha-lactalbumin with complete loss of all lysozyme functional residues.
Godovac-Zimmermann
J
J
John Curtin School of Medical Research, Australian National University, Canberra.
Conti
A
A
Napolitano
L
L
D000595:Amino Acid Sequence; D000818:Animals; D005075:Biological Evolution; D002851:Chromatography, High Pressure Liquid; D007768:Lactalbumin / Q000737:chemistry* / Q000235:genetics; D008892:Milk / Q000737:chemistry*; D008969:Molecular Sequence Data; D009113:Muramidase / Q000235:genetics; D010449:Peptide Mapping; D013552:Swine
D007768:Lactalbumin; D009113:Muramidase