Peptide Mapping Studies of the Chromogranins and of Two Chromaffin Granule Proteoglycans

Abstract

The chromogranins, a family of related acidic glycoproteins, and 2 chondroitin sulfate/dermatan sulfate proteoglycans were isolated from the soluble contents of bovine adrenal chromaffin granules by chromatography on DEAE-cellulose. These chromaffin granule matrix glycoconjugates were treated with trypsin, and the resulting peptides were fractionated by high performance liquid chromatography. The 2 proteoglycans, which differ in their concentration of glycosaminoglycans and glycoprotein oligosaccharides, yielded almost identical peptide patterns and would both appear to have the same protein moiety. The peptide profile of the proteoglycans differs from that of the chromogranins, which they closely resemble in terms of amino acid composition. The various chromogranin fractions obtained by gel filtration also had significant differences in the chromatographic patterns of their tryptic peptides.