Purification and characterization of chromogranin-A from the adrenal gland of human and bovine.

In the present study, we report a simple, highly reproducible procedure for the purification of chromogranin A. A three step column chromatography of supernatant from human and bovine provided a major single band at M(r) 67 and two minor bands at low molecular mass. Identity of the major and minor bands of CgA was confirmed by western blotting using LK2H10, a monoclonal antibody against chromogranin A. Recognition of smaller fragments in the final preparation in both species by antibody to chromogranin A may suggest that these are the proteolytic breakdown product of the main protein. Bovine adrenal gland was found to be many fold richer in chromogranin than human adrenal gland. The simplification of the purification procedure for CgA may now help in elucidating further physiological function of this protein.