Bell K, McKenzie H A, Shaw D C
Mol Cell Biochem. 1981 Mar 13;35(2):103-11. doi: 10.1007/BF02354824.
The occurrence of the dominant 'whey' protein in samples of milk from 1180 sows is examined. It exhibits genetic polymorphism with some unusual features. Although immunologically different from bovine beta-lactoglobulin, it is shown by chemical studies of the isolated protein to be a beta-lactoglobulin. Two homozygous genetic variants, designated porcine beta-lactoglobulin A and C, are isolated and their amino acid compositions and peptide maps compared. It is shown that the C variant has +1 His, -1 Gln, and +1 Asp, -1 Glu, with respect to the A variant. These variants, containing ca. 162 residues per molecule, are considered in relationship to porcine beta-lactoglobulins isolated by other workers. The sequence of the first 50 residues is determined and compared with the sequence of the bovine protein. The sequences of ca. 70% of the remaining residues is proposed on the basis of the composition of tryptic peptides and assumed homology.
对1180头母猪乳汁样本中主要“乳清”蛋白的出现情况进行了检测。它呈现出具有一些不寻常特征的遗传多态性。尽管在免疫学上与牛β-乳球蛋白不同，但对分离出的蛋白质进行化学研究表明它是一种β-乳球蛋白。分离出了两种纯合遗传变体，分别命名为猪β-乳球蛋白A和C，并比较了它们的氨基酸组成和肽图。结果表明，相对于A变体，C变体有+1个组氨酸、-1个谷氨酰胺，以及+1个天冬氨酸、-1个谷氨酸。这些变体每分子约含162个残基，并与其他研究人员分离出的猪β-乳球蛋白进行了关联分析。确定了前50个残基的序列，并与牛蛋白的序列进行了比较。根据胰蛋白酶肽段的组成和假定的同源性，提出了其余约70%残基的序列。
