DIFFERENT DEGREES OF PROCESSING OF SECRETOGRANIN-II IN LARGE DENSE CORE VESICLES OF BOVINE ADRENAL-MEDULLA AND SYMPATHETIC AXONS CORRELATE WITH THEIR CONTENT OF SOLUBLE PC1 AND PC2

We investigated the processing of secretogranin II in large dense core vesicles of adrenal medulla and sympathetic nerve. Despite the fact that both types of vesicles have a very similar biochemical composition, the degree of processing of secretogranin II in vesicles from splenic nerve was significantly higher. The endoproteases PC1 and PC2, two likely candidates for secretogranin II cleavage, are found in both types of vesicles, however, relative to secretogranin II the nerve vesicles have a much higher content of these enzymes. This probably explains the fast and more extensive processing of secretogranin II in these vesicles.