Structure-Function Relationship Studies on Parathyroid Hormone (PTH) 1–34 Analogs Containing β-Amino Acid Residues in Positions 11, 12, and 13

Parathyroid hormone (PTH) is an 84 amino acid residue peptide, which plays a key physiological role in the regulation of calcium levels in serum. Virtually, all bone-relevant activities of PTH are encoded in the fully active N-terminal 1–34 sequence [1]. On the basis of our previous results on a series of active and inactive analogs of the PTH(1–34) [2], we suggested that the structural elements essential for biological activity are an N-terminal and a C-terminal helical segments connected by hinges or flexible points around positions 12 and 19. To probe this hypothesis, in the present work we synthesized by solid phase methods, and characterized the following bPTH(1–34) analogs containing β-amino acid residues at positions 11, 12 and 13.