<p>Chromogranins and secretogranins are acidic proteins present in the secretory granules of endocrine and neuro-endocrine cells [<cite idref="PUB00005374"/>, <cite idref="PUB00000478"/>]. Granins may be precursors of biologically-active peptides, or they may be helper proteins in the packaging of peptide hormones and neuropeptides - their precise role is unclear.</p><p>Chromogranins A and B are characterised by an N-terminal motif that includes 2 cysteine residues involved in disulphide bond formation.</p> Chromogranin A/B