title: Cleavage of the Arg-Ile bond in the native polypeptide chain of human pancreatic stone protein.
abstract: The pancreatic stone protein (PSP) isolated from calculi (Mr 14,000) and the 5 protein forms (PSP S1-5) detected in pancreatic juice (Mr 14,000-19,000) derive from the same source differing seemingly in their carbohydrate contents or/and in their polypeptidic chain lengths. This kind of protein would inhibit in vivo CaCO3-crystal growth in pancreatic juice. PSP and PSP S1 N-terminal sequences are identical (NH2Ile-). This report demonstrates that: in PSP S2-5 the amino-terminal is blocked; the C-terminus is alike in every form; the single polypeptide chain of PSP S2-5 is converted into that of PSP S1 or PSP by the specific trypsin cleavage of the Arg-Ile bond.
mesh_terms: D000595:Amino Acid Sequence; D001120:Arginine; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002918:Chymotrypsin / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D007532:Isoleucine; D051847:Lithostathine; D008970:Molecular Weight; D009419:Nerve Tissue Proteins; D010179:Pancreas / Q000378:metabolism*; D010434:Pepsin A / Q000378:metabolism; D010446:Peptide Fragments / Q000032:analysis; D011499:Protein Processing, Post-Translational; D014357:Trypsin / Q000378:metabolism
chemical_list: D002135:Calcium-Binding Proteins; D051847:Lithostathine; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; C497617:REG1A protein, human; D007532:Isoleucine; D001120:Arginine; D002918:Chymotrypsin; D014357:Trypsin; D010434:Pepsin A