Insulin is produced in a step-wise process. Preproinsulin is a biologically inactive precursor that consists of an N-terminal signal peptide followed by the proinsulin molecule. Removal of the signal peptide by signal peptidases results in proinsulin alone. Proinsulin contains the A-chain, B-chain and a 31-amino-acid Connecting peptide or C-peptide. The C-peptide is positioned between the A-chain and the B-chain and functions to connect them. The C-peptide is removed once proinsulin is processed into insulin.
Antibodies to the proinsulin C-peptide (also known as insulin C) are frequently used to study the structure, function and metabolism of insulin as well as proinsulin. Insulin C antibodies can also be used for immunocytochemistry and for immunohistochemical studies of paraffin-embedded or frozen tissue sections. The following insulin C antibodies are available:
- Mouse insulin C polyclonal antibody is generated in guinea pig immunized with the KLH-conjugated mouse insulin C-peptide (71-84) [SPGDLQTLALEVAR].
- Human insulin C monoclonal antibody is generated in mouse immunized with the KLH-conjugated human insulin C-peptide (71–86) [GPGAGSLQPLALEGSL].
- Mouse insulin C monoclonal antibody is generated in rat immunized with the KLH-conjugated mouse insulin C-peptide (71–84) [SPGDLQTLALEVAR].