beta-Granins: 21 kDa co-secreted peptides of the insulin granule closely related to adrenal medullary chromogranin A.
Three closely related forms of a 21 kDa protein which is co-secreted with insulin have been purified and analysed. These differed in behaviour on ion-exchange chromatography but were indistinguishable by their susceptibility to staphylococcal V8 proteinase digestion, amino acid composition or N-terminal amino acid sequence. Their amino acid composition and N-terminal sequences were remarkably similar to adrenal medullary chromogranin A, a much larger protein (72 kDa). Antibodies to chromogranin A also reacted strongly with the 21 kDa protein in isolated insulin granules. It is concluded that the 21 kDa proteins either represent a repeated domain within the chromogranin molecule or a closely related gene product. The name beta-granin is proposed for these proteins.
D000313:Adrenal Medulla / Q000378:metabolism*; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002852:Chromatography, Ion Exchange; D053379:Chromogranin A; D002864:Chromogranins / Q000032:analysis* / Q000302:isolation & purification*; D007120:Immunochemistry; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D008970:Molecular Weight; D009419:Nerve Tissue Proteins / Q000032:analysis* / Q000302:isolation & purification*; D051381:Rats
D000596:Amino Acids; D053379:Chromogranin A; D002864:Chromogranins; D007328:Insulin; D009419:Nerve Tissue Proteins; C046560:beta-granins; C506153:chromogranin A, rat