Creutz Carl E
Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA.
Curr Protoc Cell Biol. 2010 Sep;Chapter 3:Unit 3.39.1-10. doi: 10.1002/0471143030.cb0339s48.
Adrenal medullary chromaffin granules (dense core secretory vesicles) have been a valuable model system for the study of the proteins and membrane components involved in the process of exocytosis. Because of the abundance of chromaffin granules in a readily available tissue source, bovine adrenal medullae, and their unique sedimentation properties, it is possible to obtain large quantities of highly purified granules and granule membranes in a short period of time. Two protocols are presented here for the isolation of chromaffin granules: a basic protocol based on differential centrifugation in an iso-osmotic medium that yields intact chromaffin granules, and an alternate protocol based on sedimentation through a density step gradient that provides a greater yield of more highly purified chromaffin granules. Since in the latter case the granules cannot be returned to a medium of physiological osmolarity without lysis after purification on the step gradient, the alternate protocol is more useful to obtain the granule membranes or contents for further study.
肾上腺髓质嗜铬颗粒（致密核心分泌囊泡）一直是研究胞吐作用过程中涉及的蛋白质和膜成分的重要模型系统。由于在易于获取的组织来源——牛肾上腺髓质中嗜铬颗粒丰富，且具有独特的沉降特性，因此有可能在短时间内获得大量高度纯化的颗粒和颗粒膜。本文介绍了两种分离嗜铬颗粒的方法：一种基于在等渗介质中进行差速离心的基本方法，可得到完整的嗜铬颗粒；另一种基于通过密度梯度沉降的替代方法，能获得更高产量、纯度更高的嗜铬颗粒。由于在后一种情况下，颗粒在梯度纯化后若不裂解就无法回到生理渗透压的介质中，所以替代方法对于获取颗粒膜或内容物以进行进一步研究更为有用。
