Jiménez-Clavero M A, González-Rubio C, Fontán G, López-Trascasa M
Unidad de Immunología, Hospital La Paz, Madrid, Spain.
Immunol Lett. 1994 Oct;42(3):185-90. doi: 10.1016/0165-2478(94)90084-1.
Factor J (FJ) is a new inhibitor of the complement system. This work supports the fact that FJ is a cationic molecule (pI > or = 9.6 in native conditions, or pI = 8.1 in denaturing conditions) with a high sugar content (40%) that is able to interact with different lectins, suggesting a complex glycosylation. SDS impaired FJ migration in polyacrylamide gel electrophoresis. In Triton-acid-urea-polyacrylamide gel electrophoresis FJ migrated as a complex, dispersed molecule. In contrast, FJ after Smith degradation (dFJ) gave a single, smeared band of M(r) = 23.4 kDa in reducing SDS-PAGE. dFJ retained only 60% of the initial inhibitory activity of intact FJ. When digestions with different proteinases were performed, no modification of activity was observed. After beta-glucuronidase digestion, FJ lost 80% of its initial activity. Consequently, glycosylation plays an important role in the inhibitory activity of FJ.
J因子（FJ）是补体系统的一种新型抑制剂。这项研究支持了以下事实：FJ是一种阳离子分子（天然条件下pI≥9.6，变性条件下pI = 8.1），含糖量高（40%），能够与不同的凝集素相互作用，提示存在复杂的糖基化。SDS会影响FJ在聚丙烯酰胺凝胶电泳中的迁移。在Triton-酸-尿素-聚丙烯酰胺凝胶电泳中，FJ以复杂的、分散的分子形式迁移。相比之下，经史密斯降解后的FJ（dFJ）在还原型SDS-PAGE中呈现出一条单一的、拖尾的条带，分子量为23.4 kDa。dFJ仅保留了完整FJ初始抑制活性的60%。当用不同的蛋白酶进行消化时，未观察到活性的改变。经β-葡萄糖醛酸酶消化后，FJ失去了80%的初始活性。因此，糖基化在FJ的抑制活性中起重要作用。
