Foulds L M, de Kretser D M, Farnworth P, Buttress D, Jenkin G, Groome N P, McFarlane J R
Institute of Reproduction and Development, Monash University, Clayton, Victoria 3168, Australia.
Biol Reprod. 1998 Aug;59(2):233-40. doi: 10.1095/biolreprod59.2.233.
In a preliminary study, allantoic fluid collected from pregnant sheep across gestational ages of 20-124 days contained significantly higher levels of activin bioactivity (189 +/- 74 ng/ml, mean +/- SE) than did amniotic fluid (3.2 +/- 0.6 ng/ml). Using a combination of chromatography steps, we isolated from 5 L of allantoic fluid approximately 612 microg of immunoactive activin, which eluted over 10 fractions from a C8 reversed-phase column. When these fractions were assayed in a rat pituitary cell culture bioassay, in a specific RIA, and in an activin A two-site ELISA, the RIA activity was skewed to the less hydrophobic side of the activin profile, while the bioactivity was skewed to the more hydrophobic forms. The activity measured in the two-site ELISA more closely matched the mass of activin as determined by laser densitometry. Amino-terminal sequencing of fractions containing either peak immunoactivity or bioactivity showed each to be identical to activin A. This was confirmed by internal sequences from a fraction that eluted in the area of overlapping immunoactivity and bioactivity. A peptide containing at least 18 amino acids at its amino terminus, which were identical to the conserved region of the acute-phase protein serum amyloid A, was identified in the most immunoactive activin fractions.
在一项初步研究中，从妊娠20至124天的孕羊收集的尿囊液中，激活素生物活性水平（189±74 ng/ml，平均值±标准误）显著高于羊水（3.2±0.6 ng/ml）。通过一系列色谱步骤，我们从5升尿囊液中分离出约612微克免疫活性激活素，这些激活素从C8反相柱上洗脱下来，共分为10个组分。当用大鼠垂体细胞培养生物测定法、特异性放射免疫测定法（RIA）和激活素A双位点酶联免疫吸附测定法（ELISA）对这些组分进行检测时，RIA活性偏向激活素图谱中疏水性较低的一侧，而生物活性则偏向疏水性更强的形式。双位点ELISA测定的活性与激光密度测定法确定的激活素质量更接近。对含有免疫活性或生物活性峰值的组分进行氨基末端测序，结果表明每个组分均与激活素A相同。从免疫活性和生物活性重叠区域洗脱的一个组分的内部序列也证实了这一点。在免疫活性最强的激活素组分中，鉴定出一种在氨基末端含有至少18个氨基酸的肽，这些氨基酸与急性期蛋白血清淀粉样蛋白A的保守区域相同。
