Reddy G K, Hudson B G, Bailey A J, Noelken M E
Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City 66160-7421.
Biochem Biophys Res Commun. 1993 Jan 15;190(1):277-82. doi: 10.1006/bbrc.1993.1042.
The subunits of the collagen IV hexameric, noncollagenous NC1 domain obtained from bovine aorta, glomerular basement membrane, alveolar basement membrane and placental basement membrane are predominantly dimers. A large fraction of the dimers had been thought to be linked by nondisulfide bonds because they were resistant to cleavage by 5% (v/v) 2-mercaptoethanol, 2% (w/v) SDS, at 100 degrees C. However, if an unusually high concentration of 2-mercaptoethanol, e.g., 40% (v/v), is used, complete conversion of dimers into monomers is achieved, indicating the lack of intersubunit nondisulfide cross-links. Electrophoresis patterns indicate that some of the intermolecular disulfide bonds of the dimers are more resistant to reduction in aqueous SDS than are some of the intramolecular disulfide bonds.
从牛主动脉、肾小球基底膜、肺泡基底膜和胎盘基底膜获得的IV型胶原六聚体非胶原NC1结构域的亚基主要是二聚体。大部分二聚体被认为是通过非二硫键连接的，因为它们在100℃下对5%（v/v）2-巯基乙醇、2%（w/v）十二烷基硫酸钠（SDS）的裂解具有抗性。然而，如果使用异常高浓度的2-巯基乙醇，例如40%（v/v），则可实现二聚体完全转化为单体，这表明不存在亚基间非二硫交联。电泳图谱表明，二聚体的一些分子间二硫键比一些分子内二硫键在水性SDS中更难被还原。
