Jacobs K A, Phelps D S, Steinbrink R, Fisch J, Kriz R, Mitsock L, Dougherty J P, Taeusch H W, Floros J
J Biol Chem. 1987 Jul 15;262(20):9808-11.
Mammalian surfactant is an incompletely defined mixture of lipids and associated proteins of molecular mass 35,000 Da and approximately 6,000 Da. Surfactant preparations which are highly effective in treating respiratory distress syndrome in premature infants lack the 35-kDa proteins, but contain the 6-kDa proteins. We isolated and partially sequenced one of these low molecular weight proteins from the lung lavage material of an alveolar proteinosis patient. Oligonucleotides deduced from the sequence were used as probes to isolate a human cDNA clone. The clone codes for a 42-kDa protein which contains the sequence of the 6-kDa protein. Messenger RNA coding for the 42-kDa protein was identified in human lung RNA by in vitro translation and immunoprecipitation of the translation products with an antiserum against purified bovine surfactant 6-kDa proteins. Immunoprecipitation of the 42-kDa primary translation product is inhibited by the presence of the bovine 6-kDa protein. These observations suggest a precursor-product relationship of the 42-kDa protein to one of the 6-kDa proteins.
哺乳动物表面活性剂是一种成分尚未完全明确的脂质与相关蛋白质的混合物，这些蛋白质的分子量分别为35,000道尔顿和约6,000道尔顿。在治疗早产儿呼吸窘迫综合征方面非常有效的表面活性剂制剂不含35 kDa的蛋白质，但含有6 kDa的蛋白质。我们从一名肺泡蛋白沉积症患者的肺灌洗材料中分离出一种低分子量蛋白质，并对其进行了部分测序。从该序列推导的寡核苷酸用作探针来分离人cDNA克隆。该克隆编码一种42 kDa的蛋白质，其包含6 kDa蛋白质的序列。通过体外翻译以及用抗纯化牛表面活性剂6 kDa蛋白质的抗血清对翻译产物进行免疫沉淀，在人肺RNA中鉴定出编码42 kDa蛋白质的信使RNA。牛6 kDa蛋白质的存在会抑制42 kDa初级翻译产物的免疫沉淀。这些观察结果表明42 kDa蛋白质与其中一种6 kDa蛋白质之间存在前体-产物关系。
