title: Identification and the primary structure of equine alpha-lactalbumin B and C (Equus caballus, Perissodactyla).
abstract: The presence of two new alpha-lactalbumins has been demonstrated in the colostrum of a single mare (Equus caballus, Persian Arab). They have been designated equine alpha-lactalbumin B and C, and that isolated previously from the milk of Australian horses (English Thoroughbred) as alpha-lactalbumin A. The primary structures of B/C have been determined by automatic Edman degradation of enzymatic cleavage of the oxidized protein. Cyanogen bromide cleavage of S-carbamoyl-methylated protein provided necessary overlapping peptides. Comparison of the sequences of B and C with that of A indicates 3 and 4 amino-acid exchanges, respectively. The phylogenetic difference of equine alpha-lactalbumin B/C from bovine alpha-lactalbumin B is indicated by 39 and 40 amino-acid exchanges, respectively. The structure-function relationship, calcium binding sites and variants of alpha-lactalbumin are discussed.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003126:Colostrum; D005260:Female; D006736:Horses / Q000378:metabolism*; D007768:Lactalbumin / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D007768:Lactalbumin; D002118:Calcium