Wood D C, Salsgiver W J, Kasser T R, Lange G W, Rowold E, Violand B N, Johnson A, Leimgruber R M, Parr G R, Siegel N R
Monsanto Company, Saint Louis, Missouri 63198.
J Biol Chem. 1989 Sep 5;264(25):14741-7.
Bovine somatotropin (bST) has been isolated from pituitary glands and compared in a variety of chemical analyses and bioassays with somatotropin derived from recombinant Escherichia coli. Comparison of pituitary extracts and purified bST by Western blot analysis of two-dimensional gels suggested that the immunoreactive somatotropin species present in the extract were also present in the purified material, with no significant losses or degradation as a result of the purification method. NH2-terminal sequence analysis indicated the presence of equal quantities of Ala-Phe-Pro-Ala-Met-Ser-Leu-Ser- and Phe-Pro-Ala-Met-Ser-Leu-Ser- sequences. The Met-Ser-Leu-Ser-NH2-terminal sequence, a degradation product observed in NIH standard lots, was not detected. Assay of bioactivity in a bovine liver receptor-binding assay and in a female rat growth assay showed pituitary bST and recombinant methionyl-bovine somatotropin to be equipotent. Tryptic maps and sequence analysis of pituitary-derived somatotropin suggest the presence of isoaspartate derivatization at Asp128.
牛生长激素（bST）已从垂体中分离出来，并在各种化学分析和生物测定中与源自重组大肠杆菌的生长激素进行了比较。通过二维凝胶的蛋白质印迹分析对垂体提取物和纯化的bST进行比较表明，提取物中存在的免疫反应性生长激素种类也存在于纯化物质中，纯化方法未导致明显损失或降解。氨基末端序列分析表明存在等量的Ala-Phe-Pro-Ala-Met-Ser-Leu-Ser-和Phe-Pro-Ala-Met-Ser-Leu-Ser-序列。未检测到在NIH标准批次中观察到的降解产物Met-Ser-Leu-Ser-氨基末端序列。在牛肝受体结合测定和雌性大鼠生长测定中的生物活性测定表明，垂体bST和重组甲硫氨酰牛生长激素具有同等效力。垂体来源的生长激素的胰蛋白酶图谱和序列分析表明，在Asp128处存在异天冬氨酸衍生化。
