Isolation and characterization of a Golgi-rich fraction from the adrenal medulla.

1. A Golgi-rich fraction from bovine adrenal medulla was isolated by centrifugation through discontinuous sucrose density gradients. 2. The specific activity of UDPgalactose-N-acetylglucosamine galactosyl transferase was increased in this fraction. Therefore, this enzyme is a useful marker for Golgi in bovine adrenal medulla. 3. Golgi membranes were reasonably free from mitochondria, lysosomes, endoplasmic reticulum and chromaffin granules as shown by the relatively low activities of marker enzymes. 4. The negative staining techniques of electron microscopy revealed the presence of a system of tubules, vesicles and plate-like center regions which are similar to those structures previously described of the Golgi fraction isolated from the liver. 5. The specific activity of 5'-nucleotidase in the Golgi-rich fraction was 3.5 times greater than that in adrenal homogenates. However, the subcellular distribution patterns of galactosyl transferase and 5'-nucleotidase were similar. The possibility that 5'-nucleotidase might be a conspicious component of the Golgi apparatus is discussed.