title: Primary structure of water buffalo alpha-lactalbumin variants A and B.
abstract: A novel electrophoretic alpha-lactalbumin (alpha-la) variant was detected in the Italian water buffalo breed. The isoelectric point of the variant, labelled A, was lower than the most frequent variant B. It presented an allelic frequency of 0.5% compared with the 97.1% of the BB allele. From Liquid Chromatography-Electrospray Ionization/Mass spectrometry, the molecular mass of the two alpha-la A and B variants were measured as 14,235.1+/-0.8 and 14,236.1+/-0.9 Da, respectively. The two proteins were sequenced and differentiated from one another by a single amino acid substitution, Asn45(B)-->Asp45(A). As this amino acid substitution altered the N-glycosylation sequence consensus Asn45-X-Ser46 it may be deduced that the protein glycosylation level of the alpha-la A would decrease.
authors.affiliation: Dipartimento di Scienza degli Alimenti, Università degli Studi di Napoli Federico II, Portici, Italy. chianese@unina.it
authors.forename: Lina
authors.initials: L
authors.lastname: Chianese
authors.forename: Simonetta
authors.initials: S
authors.lastname: Caira
authors.forename: Sergio
authors.initials: S
authors.lastname: Lilla
authors.forename: Fabiana
authors.initials: F
authors.lastname: Pizzolongo
authors.forename: Pasquale
authors.initials: P
authors.lastname: Ferranti
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pugliano
authors.forename: Francesco
authors.initials: F
authors.lastname: Addeo
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D002020:Buffaloes; D002851:Chromatography, High Pressure Liquid; D005787:Gene Frequency; D014644:Genetic Variation; D006031:Glycosylation; D015151:Immunoblotting; D007525:Isoelectric Focusing; D007768:Lactalbumin / Q000737:chemistry* / Q000235:genetics; D008894:Milk Proteins / Q000737:chemistry; D008969:Molecular Sequence Data; D021241:Spectrometry, Mass, Electrospray Ionization; D000067816:Whey Proteins
chemical_list: D008894:Milk Proteins; D000067816:Whey Proteins; D007768:Lactalbumin