Sahu S, Lynn W S
Biochem J. 1979 Jan 1;177(1):153-8. doi: 10.1042/bj1770153.
A high-molecular-weight glycoprotein was isolated, purified and partially characterized from the insoluble pulmonary secretions accumulating in lungs of patients suffering from pulmonary alveolar proteinosis. On electrophoresis in 5% polyacrylamide gel in the presence of sodium dodecyl sulphate and 2-mercaptoethanol, the purified protein gave one major band as detected by Coomassie Blue as well as with periodic acid/Schiff staining. An apparent mol.wt. of 250000 was estimated for this glycoprotein. Amino acid analysis showed that it contains hydroxyproline, and relatively high amounts of glycine, glutamic acid, aspartic acid and leucine. It contains approx. 6% hexose, 3% sialic acid and 2% glucosamine. The neutral sugars are galactose, mannose and fucose. An antiserum prepared in rabbits against this high-molecular-weight glycoprotein cross-reacted with two smaller glycoproteins (mol.wts. 62000 and 36000) isolated from the same pulmonary secretions of these patients. A complementary observation was also made when this large alveolar glycoprotein cross-reacted with an antiserum prepared in rabbits against the smaller glycoprotein (mol.wt. 36000). It appears that this high-molecular-weight glycoprotein may be the precursor of the two smaller glycoproteins present in the same diseased pulmonary secretions.
从肺泡蛋白沉积症患者肺部积聚的不溶性肺分泌物中分离、纯化并对一种高分子量糖蛋白进行了部分特性鉴定。在十二烷基硫酸钠和2-巯基乙醇存在的条件下，于5%聚丙烯酰胺凝胶中进行电泳，考马斯亮蓝染色以及高碘酸/席夫染色均显示纯化后的蛋白呈现一条主要条带。估计该糖蛋白的表观分子量为250000。氨基酸分析表明它含有羟脯氨酸，以及相对大量的甘氨酸、谷氨酸、天冬氨酸和亮氨酸。它含有约6%的己糖、3%的唾液酸和2%的氨基葡萄糖。中性糖为半乳糖、甘露糖和岩藻糖。用兔制备的针对这种高分子量糖蛋白的抗血清与从这些患者相同肺分泌物中分离出的两种较小的糖蛋白（分子量分别为62000和36000）发生交叉反应。当这种大的肺泡糖蛋白与用兔制备的针对较小糖蛋白（分子量36000）的抗血清发生交叉反应时，也观察到了互补现象。看来这种高分子量糖蛋白可能是同一患病肺分泌物中两种较小糖蛋白的前体。
