A method of synthesizing a modified therapeutic peptide capable of forming a peptidase-stabilized therapeutic peptide conjugate, the peptide having between 3 and 50 amino acids, is k. In a first step of the method, a therapeutic peptide having a carboxy terminal amino acid and amino terminal amino acid is synthesized. In a second step, pairs of cysteine residues present in the therapeutic peptide are sequentially and selectively oxidized to form disulfide bridges in the therapeutic peptide. In a third step, a protecting group is attached to remaining cysteine residues that do not form disulfide bridges in the therapeutic peptide. Finally, the peptide is coupled to a reactive group capable of reacting with amino groups, hydroxyl groups or thiol groups on a blood component to form a covalent bond therewith.