Ramshaw J A, Bateman J F, Cole W G
Anal Biochem. 1984 Sep;141(2):361-5. doi: 10.1016/0003-2697(84)90056-3.
Types I, II, and III collagens are readily precipitated at neutral pH by polyethylene glycols (PEG). As the molecular weight fraction of the polyethylene glycols increases, they become more effective as precipitants on a weight basis. The amount of PEG required for precipitation depends on the pH, the ionic strength, and the nature of the buffer or salts present. In tissue culture media, low concentrations of collagens and procollagens may be quantitatively precipitated and readily collected by low-speed centrifugation. Polyethylene glycol precipitation can be used to obtain collagens and procollagens from tissue culture media at either analytical or preparative scale, and since the polyethylene glycols do not bind to collagens, the precipitates may be further analyzed directly by chromatographic or electrophoretic methods.
I型、II型和III型胶原蛋白在中性pH条件下很容易被聚乙二醇（PEG）沉淀。随着聚乙二醇分子量分数的增加，按重量计算，它们作为沉淀剂的效果会更好。沉淀所需的PEG量取决于pH值、离子强度以及存在的缓冲液或盐的性质。在组织培养基中，低浓度的胶原蛋白和前胶原蛋白可以通过低速离心进行定量沉淀并轻松收集。聚乙二醇沉淀法可用于从组织培养基中以分析或制备规模获得胶原蛋白和前胶原蛋白，并且由于聚乙二醇不与胶原蛋白结合，沉淀物可直接通过色谱或电泳方法进一步分析。
