Wood W I, Cachianes G, Henzel W J, Winslow G A, Spencer S A, Hellmiss R, Martin J L, Baxter R C
Department of Developmental Biology, Genentech, Inc., South San Francisco, California 94080.
Mol Endocrinol. 1988 Dec;2(12):1176-85. doi: 10.1210/mend-2-12-1176.
N-terminal as well as internal amino acid sequence data were obtained from the GH dependent, insulin-like growth factor (IGF) binding protein, BP-53, purified from human plasma. Based on these sequence data, full-length cDNA clones of BP-53 have been isolated, and the complete deduced sequence of BP-53 determined. This sequence contains a 27 amino acid putative signal sequence followed by a mature protein of 264 amino acids containing 18 cysteine residues clustered near the N- and C-terminus. The deduced protein sequence of BP-53 has 33% amino acid identity including conservation of all 18 cysteine residues with the recently cloned BP-28, a smaller human IGF-binding protein identified in amniotic fluid and also secreted by the cell line HEP G2. Expression of the cloned BP-53 cDNA in mammalian tissue culture cells results in secretion of the protein into the culture medium. This expressed protein is identical to plasma-derived BP-53 in its immunoreactivity, high affinity binding of IGF-I and IGF-II, and mobility on sodium dodecyl sulfate gel electrophoresis.
从人血浆中纯化出的生长激素依赖性胰岛素样生长因子（IGF）结合蛋白BP - 53获得了N端以及内部氨基酸序列数据。基于这些序列数据，分离出了BP - 53的全长cDNA克隆，并确定了BP - 53完整的推导序列。该序列包含一个27个氨基酸的假定信号序列，其后是一个由264个氨基酸组成的成熟蛋白，其中18个半胱氨酸残基聚集在N端和C端附近。BP - 53的推导蛋白序列与最近克隆的BP - 28有33%的氨基酸同一性，包括所有18个半胱氨酸残基的保守性，BP - 28是在羊水和细胞系HEP G2中也分泌的一种较小的人IGF结合蛋白。在哺乳动物组织培养细胞中克隆的BP - 53 cDNA的表达导致该蛋白分泌到培养基中。这种表达的蛋白在免疫反应性、对IGF - I和IGF - II的高亲和力结合以及在十二烷基硫酸钠凝胶电泳上的迁移率方面与血浆来源的BP - 53相同。
