Isolation and characterization of a tumor-derived human protein related to chromogranin A and its in vitro conversion to human pancreastatin-48.
A protein with pancreastatin-like immunoreactivity has been isolated and purified from liver metastasis of a patient with insulinoma. NH2-terminal residue analysis, in conjunction with the use of antibodies that are specific for the C-terminal amide peptide of porcine pancreastatin, identified this protein as a 186-amino-acid protein corresponding to human chromogranin A-116-301 (the fragment corresponding to the positions from 116 to 301 of human chromogranin A). Digestion of this protein with trypsin yielded a 48-amino-acid peptide with the retention of full pancreastatin activity. Serum from patient with insulinoma contains a peptide specie(s) that comigrates with the 48-amino-acid pancreastatin, suggesting that this peptide might be a physiologically important circulation form of pancreastatin in humans. A sensitive radioimmunoassay was established using antibody developed against a synthetic 29-amino-acid peptide amide of pancreastatin. Immunocytochemical staining revealed that a major population of human pancreatic islet cells were immunoreactive to the antiserum but with varying intensity of staining. Pancreastatin-like immunoreactivity was not observed in exocrine acinar cells.
Tamamura
H
H
Faculty of Pharmaceutical Sciences, Kyoto University, Japan.
Ohta
M
M
Yoshizawa
K
K
Ono
Y
Y
Funakoshi
A
A
Miyasaka
K
K
Tateishi
K
K
Jimi
A
A
Yajima
H
H
Fujii
N
N
D007516:Adenoma, Islet Cell / Q000378:metabolism*; D000595:Amino Acid Sequence; D000906:Antibodies / Q000032:analysis; D053379:Chromogranin A; D002864:Chromogranins / Q000032:analysis* / Q000138:chemical synthesis; D006801:Humans; D007150:Immunohistochemistry; D007340:Insulinoma / Q000032:analysis / Q000378:metabolism* / Q000556:secondary; D008113:Liver Neoplasms / Q000556:secondary; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000032:analysis*; D010187:Pancreatic Hormones / Q000032:analysis / Q000302:isolation & purification*; D011863:Radioimmunoassay; D014357:Trypsin
D000906:Antibodies; C506150:CHGA protein, human; D053379:Chromogranin A; D002864:Chromogranins; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D010187:Pancreatic Hormones; C050836:pancreastatin; D014357:Trypsin