represents Proinsulin: This is the inactive precursor or prohormone form synthesized by the pancreas. It contains three continuous chains: the A-peptide, B-peptide, and an extra connecting stretch called the C-peptide.

represents the A-peptide: This is the shorter polypeptide chain (21 amino acids) found in both proinsulin and mature insulin. It contains an intra-chain disulfide bond.

represents the B-peptide: This is the longer polypeptide chain (30 amino acids) that pairs with the A-peptide to form the functional hormone.

represents the Free C-peptide: During the proteolytic processing and maturation of proinsulin, enzymatic cleavage removes this connecting strand. As a result, it detaches completely and is not part of the active, mature insulin molecule.

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