Usselman M C, Cone R A, Rossignol D P
J Androl. 1985 Sep-Oct;6(5):315-20. doi: 10.1002/j.1939-4640.1985.tb00851.x.
Immobilin, the highly viscoelastic glycoprotein isolated from rat cauda epididymal fluid, exhibits all of the key biochemical characteristics of a mucin: 1) it has a very high molecular weight (will not pass through a 10(6) dalton cut-off filter; 2) it contains 56% carbohydrate, with low or undetectable levels of mannose, xylose and uronic acid; 3) the carbohydrates (primarily galactose, N-acetylglucosamine and N-acetylgalactosamine) are arranged in short, oligosaccharide chains (4-20 monosaccharides per chain); 4) these oligosaccharide chains can be cleaved by NaOH in the presence of NaBH4, suggesting O-glycosidic linkages; and 5) the protein core is pronase-resistant. Immobilin, however, contains no detectable sialic acid, and 67% of the oligosaccharides are uncharged, indicating that immobilin is less acidic than most other mucins.
Immobilin是从大鼠附睾尾部液体中分离出的高度粘弹性糖蛋白，具有粘蛋白的所有关键生化特性：1）它的分子量非常高（不能通过10^6道尔顿截留滤器）；2）它含有56%的碳水化合物，甘露糖、木糖和糖醛酸含量低或检测不到；3）碳水化合物（主要是半乳糖、N-乙酰葡糖胺和N-乙酰半乳糖胺）排列成短的寡糖链（每条链含4-20个单糖）；4）在NaBH4存在下，这些寡糖链可被NaOH裂解，表明存在O-糖苷键；5）蛋白质核心对链霉蛋白酶有抗性。然而，Immobilin不含可检测到的唾液酸，67%的寡糖不带电荷，这表明Immobilin的酸性低于大多数其他粘蛋白。
