Chen B L, Arakawa T, Morris C F, Kenney W C, Wells C M, Pitt C G
Department of Pharmaceutics and Drug Delivery, Amgen Inc., Thousand Oaks, CA 91320.
Pharm Res. 1994 Nov;11(11):1581-7. doi: 10.1023/a:1018905720139.
Recombinant human keratinocyte growth factor (rhKGF) is prone to aggregation at elevated temperatures. Its aggregation pathway is proposed to proceed initially with a conformational change which perhaps results from repulsion between positively charged residues in clusters forming heparin binding sites. Unfolding of the protein leads to formation of large soluble aggregates. These soluble aggregates then form disulfide cross-linked precipitates. Finally these precipitates are converted to scrambled disulfides and/or non-disulfide cross-linked precipitates. Stabilizers such as heparin, sulfated polysaccharides, anionic polymers and citrate can greatly decrease the rate of aggregation of rhKGF at elevated temperatures. These molecules may all act by reducing charge repulsion on the protein thus stabilizing the native conformation. EDTA, on the other hand, is found to inhibit disulfide formation in aggregates and has only a moderate stabilizing effect on rhKGF.
重组人角质形成细胞生长因子（rhKGF）在温度升高时易于聚集。其聚集途径被认为最初是通过构象变化进行的，这可能是由于形成肝素结合位点的簇中带正电荷的残基之间的排斥作用所致。蛋白质的解折叠导致形成大的可溶性聚集体。这些可溶性聚集体随后形成二硫键交联的沉淀物。最后，这些沉淀物转化为混乱的二硫键和/或非二硫键交联的沉淀物。诸如肝素、硫酸化多糖、阴离子聚合物和柠檬酸盐等稳定剂可以大大降低rhKGF在温度升高时的聚集速率。这些分子可能都通过减少蛋白质上的电荷排斥作用来发挥作用，从而稳定天然构象。另一方面，发现EDTA可抑制聚集体中二硫键的形成，并且对rhKGF只有适度的稳定作用。
