Osmotic fragility of chromaffin granules prepared under isoosmotic or hyperosmotic conditions and localization of acetylcholinesterase

• Published in: Biochimica et biophysica acta, Protein structure and molecular enzymology Vol. 839; no. 3; pp. 219 - 227
• Main Authors: Burgun, C, Martinez de Munoz, D, Aunis, D
• Format: Journal Article
• Language: English
• Published: 01.01.1985
• Subjects: acetylcholinesterase; cattle; chromaffin granules
• ISSN: 0167-4838

In chromaffin cells of the adrenal medulla, catecholamines are stored in secretory granules. In the present study, storage granules were prepared using isoosmotic self-generating Percoll gradients or hyperosmotic sucrose gradients, and a comparison of their physical properties in response to osmotic changes was made. Acetylcholinesterase activity was found to be associated with both isoosmotically and hyperosmotically prepared granules. When granules were suspended in hypoosmotic buffers, a soluble acetylcholinesterase form was released into the external medium, while an insoluble acetylcholinesterase form was still found sociated with the membrane fraction. Soluble acetylcholine sterase was found to be released differently than soluble dopamine beta -hydroxylase, indicating that acetylcholinesterase may be associated with a more osmotically resistant granule population.