Table 1 Ki values (nM) of Somatostatin, [D-Trp8]-SRIF, Octreotide and Somatostatin analogs to receptors SSTR1–5.

From: Peptide aromatic interactions modulated by fluorinated residues: Synthesis, structure and biological activity of Somatostatin analogs containing 3-(3′,5′difluorophenyl)-alanine

  SSTR1 SSTR2 SSTR3 SSTR4 SSTR5
Somatostatin (SRIF) 1.88 0.016 0.25 1.55 0.76
Octreotide >300 0.770 13.0 >300 21.0
1 [L-Dfp6,D-Trp8]-SRIF 21.0 0.350 0.38 16.0 5.02
2 [L-Dfp7,D-Trp8]-SRIF 14.0 0.360 1.10 12.0 2.10
3 [D-Trp8,L-Dfp11]-SRIF 14.0 0.066 3.81 11.0 5.00
4 [L-Dfp6,L-Msa7,D-Trp8]-SRIF 38.0 0.170 5.46 150 82.0
5 [L-Msa7,D-Trp8.L-Dfp11]-SRIF 19.0 0.260 23.0 62.0 31.0
6 [L-Dfp6,11,L-Msa7,D-Trp8]-SRIF 55.0 0.310 12.0 63.0 45.0
  1. Shaded cells represent data close to the Somatostatin values. The binding measurements were performed by Eurofins Panlabs Taiwan, Ltd.