ABSTRACT
The chromogranins comprise a family of acidic polypeptides, which are the major soluble proteins in the cytoplasmic catecholamine storage granules of adrenal medullary cells and sympathetic nerves [1-11]. It has long been recognized that they have several molecular weights, but some uncertainty still exists as to whether these are independently synthesized molecules or the products of proteolysis of a large "parent" molecule. In particular, Kirshner and Kirshner have demonstrated that one chromogranin moiety with a molecular weight (MW) of 81.2 kilodaltons (kD) represents a dimer of two identical 40.6 kD subunits [12]. Others have described chromogranin molecules ranging in MW from 33 to 100 kD [13]. Nevertheless, the major components in this family of proteins appear to cluster around 65-68 kD [14,15].
