title: The unusual amino acid triplet Asn-Ile-Cys is a glycosylation consensus site in human alpha-lactalbumin.
abstract: Human alpha-lactalbumin has not been described as a glycoprotein, despite the fact that several alpha-lactalbumins of both ruminant and nonruminant species are known to be glycosylated. In all these species the glycosylation site is the 45Asn in the usual triplet 45Asn-Gly/Gln-47Ser. We have found that human alpha-lactalbumin is glycosylated and the glycosylation site has been determined by protein sequencing and mass spectrometry. We report an unusual glycosylation site at 71Asn in the triplet 71Asn-Ile-73Cys, which is conserved in all known alpha-lactalbumins except red-necked wallaby. That a relatively small proportion of the protein is glycosylated (about 1%) may reflect the importance of this region of the protein sequence to the molten globule state of alpha-lactalbumin.
authors.affiliation: Centro Studio Alimentazione Animali, CNR, Torino, Italy.
authors.forename: M G
authors.initials: MG
authors.lastname: Giuffrida
authors.forename: M
authors.initials: M
authors.lastname: Cavaletto
authors.forename: C
authors.initials: C
authors.lastname: Giunta
authors.forename: B
authors.initials: B
authors.lastname: Neuteboom
authors.forename: A
authors.initials: A
authors.lastname: Cantisani
authors.forename: L
authors.initials: L
authors.lastname: Napolitano
authors.forename: V
authors.initials: V
authors.lastname: Calderone
authors.forename: J
authors.initials: J
authors.lastname: Godovac-Zimmermann
authors.forename: A
authors.initials: A
authors.lastname: Conti
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites / Q000502:physiology; D017124:Conserved Sequence; D005260:Female; D006031:Glycosylation; D006801:Humans; D007768:Lactalbumin / Q000737:chemistry*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009842:Oligopeptides; D017421:Sequence Analysis
chemical_list: D009842:Oligopeptides; D007768:Lactalbumin