Katyal S L, Singh G, Ryan L, Gottron S
Department of Pathology, University of Pittsburgh, School of Medicine, Pennsylvania 15261.
Exp Lung Res. 1988;14(5):655-69. doi: 10.3109/01902148809087835.
Pulmonary surfactant isolated from a number of animal species contains a protein of molecular weight 38,000 and several very hydrophobic proteins soluble in solvents often used to extract lipids. Although found to be intimately associated with surfactant lipids, localization of the very hydrophobic proteins to alveolar epithelial type II cells, the cells involved in the synthesis and secretion of pulmonary surfactant, has not been demonstrated. Hydrophobic proteins were extracted along with lipids from human surfactant, and, after extraction with deoxycholate, were used to raise an antiserum. The antiserum was characterized by the immunoblotting ("Western") technique, using blots of pulmonary surfactant, and of hydrophobic proteins prepared by deoxycholate extraction and by Sephadex LH-20 chromatography. The antiserum shows reactivity to a 6.5- to 18-kDa surfactant-associated hydrophobic protein, which appears to be the major component of deoxycholate extracted proteins, and has Phe as the N-terminal amino acid. In addition, 28-kDa, 40-kDa, 50-kDa, and 70-kDa bands (chemically unreduced) are seen in human pulmonary surfactant. Whether these bands represent precursors of the major surfactant-associated hydrophobic proteins, different proteolytic cleavage products of the precursor protein, distinct proteins, or associated forms of the same protein is not yet clear. When used in the immunoperoxidase staining of human lung sections, the antiserum yielded a staining pattern identical to that obtained by the use of an antiserum to the 35-kDa surfactant protein. The number, size, and location of the stained cells are consistent with their being the alveolar epithelial type II cells.
从多种动物物种中分离出的肺表面活性物质含有一种分子量为38,000的蛋白质以及几种非常疏水的蛋白质，这些蛋白质可溶于常用于提取脂质的溶剂中。尽管发现这些非常疏水的蛋白质与表面活性物质脂质密切相关，但尚未证实它们在肺泡II型上皮细胞（参与肺表面活性物质合成和分泌的细胞）中的定位。疏水蛋白与脂质一起从人表面活性物质中提取出来，在用脱氧胆酸盐提取后，用于制备抗血清。通过免疫印迹（“Western”）技术对抗血清进行表征，使用肺表面活性物质以及通过脱氧胆酸盐提取和葡聚糖凝胶LH - 20色谱法制备的疏水蛋白的印迹。该抗血清对一种6.5至18 kDa的与表面活性物质相关的疏水蛋白具有反应性，该蛋白似乎是脱氧胆酸盐提取蛋白的主要成分，并且以苯丙氨酸作为N端氨基酸。此外，在人肺表面活性物质中可见28 kDa、40 kDa、50 kDa和70 kDa的条带（化学未还原）。这些条带是代表主要与表面活性物质相关的疏水蛋白的前体、前体蛋白的不同蛋白水解裂解产物、不同的蛋白质还是同一蛋白质的相关形式尚不清楚。当用于人肺切片的免疫过氧化物酶染色时，该抗血清产生的染色模式与使用针对35 kDa表面活性物质蛋白的抗血清所获得的染色模式相同。染色细胞的数量、大小和位置与它们是肺泡II型上皮细胞一致。
