Lehrman S R, Lahm H W, Miedel M C, Hulmes J D, Li C H
Department of Protein Biochemistry, Roche Research Center, Hoffmann-La Roche Inc., Nutley, NJ.
Int J Pept Protein Res. 1988 Jun;31(6):544-54. doi: 10.1111/j.1399-3011.1988.tb00913.x.
Equine prolactin was determined to be a single chain protein of 199 amino acid containing two tryptophan and six cysteine residues, as found in other mammalian prolactins. The primary sequence of equine prolactin was obtained by automated Edman analyses of S-carboxymethylated protein and proteolytic fragments of modified protein. Of the known prolactin sequences, equine prolactin shows closest homology with porcine (93%) and fin whale (87-91%) prolactins. Genetic mutations have produced changes in 17 of 199 residues of equine prolactin relative to its putative ancestral precursor. Since equine growth hormone has undergone alterations in 4 of 191 residues relative to this putative precursor protein, these results support the theory that prolactins are evolving at a faster rate than growth hormones. Consistent with the previously determined circular dichroic spectrum of equine prolactin, 60% of the protein is predicted to form alpha helices.
马催乳素被确定为一种由199个氨基酸组成的单链蛋白质，含有两个色氨酸和六个半胱氨酸残基，这与其他哺乳动物的催乳素情况相同。马催乳素的一级序列是通过对S-羧甲基化蛋白和修饰蛋白的蛋白水解片段进行自动埃德曼分析获得的。在已知的催乳素序列中，马催乳素与猪催乳素（93%）和长须鲸催乳素（87 - 91%）显示出最密切的同源性。相对于其假定的祖先前体，基因突变导致马催乳素199个残基中的17个发生了变化。由于相对于这种假定的前体蛋白，马生长激素在191个残基中的4个发生了改变，这些结果支持了催乳素比生长激素进化速度更快的理论。与先前测定的马催乳素圆二色光谱一致，预计该蛋白质的60%会形成α螺旋。
