To obtain a modified polypeptide compound, effective in preventing and treating calcium metabolic diseases and orally administrable without being influenced with a proteolytic enzyme present in a mucous membrane of an alimentary canal by partially replacing an amino acid sequence of a natural type calcitonin.
This new modified polypeptide compound has an amino acid sequence of the formula (residues Cys which are an amino acid residue at the 1st and 7th positions is bonded to disulfide bonds; Hse.NH2 is homoserinamide) and an ≤18C acyl group bonded to α-amino group of Cys at the N-terminal. The polypeptide is obtained by replacing the prolinamide at the C-terminal of a natural type calcitonin with a homoserinamide and effective in preventing and treating calcium metabolic diseases and can orally be administered. The compound is obtained by synthesizing a peptide chain having an amino acid sequence of calcitonin according to a peptide solid-phase synthetic method, transducing the homoserinamide group into the C-terminal and further transducing an acyl group such as hexanoyl group into the N-terminal.
YOSHINA SHIGEAKI
ISHIDA TSUTOMU
TOMITANI NOBORU
