| [ Summary ] |
All calcitonins are composed of 32 amino acids with a disulfide bridge between positions 1 and 7, and a C-terminal prolinamide residue. From studies of calcitonin derivatives with deleted amino acid residues, des-Len19, Gln20, Thr22, Thr22-salmon calcitonin was shown to exhibit the same activity as natural salmon calcitonin. The substitution of the N-terminal amino acid from a disulfide bond to another peptide and the replacement of the C-terminal amino acid from prolinamide to homoserineamide exhibited the same activity as the natural hormone. [N alpha-Propionyl Di-Ala1, 7, des-Leu19]-salmon calcitonin possesses the same bone resorption inhibition activity and hypocalcemic effect as salmon calcitonin, but does not cause body weight loss when dosed to rats. [Leu12, 16, 19, Tyr22]-human calcitonin exhibited 20 times greater activity than human calcitonin. |