Distribution of enkephalin-containing peptides within bovine chromaffin granules

The distribution of large enkephalin-containing peptides (ECP's) between soluble and membrane components of bovine chromaffin granules was examined by immunoblotting with synenkephalin antiserum which recognizes the NH2-terminus of proenkephalin. Immunoblots showed that the 23.3 and 18.2 kilodalton ECP's were present in both soluble and membrane granule compartments but the 12.6 kilodalton ECP was present only in the soluble fraction. These results suggest that the larger ECP's may be preferentially associated with the granule membrane and may be redistributed to the soluble granule compartment upon proteolytic processing.