Table 1. In vitro GLP-1R, GIPR, and GCGR activity of peptide analogs.

EC50 values represent the effective peptide concentrations (nM) that stimulate half-maximum activation at the GLP-1R, GIPR, and GCGR. A minimum of three separate experiments was conducted for each analog at each respective receptor. Relative % activity at each receptor = (native ligand EC50/analog EC50) × 100. Underlined residues in peptide 10 represent residues featuring a side-chain lactam bridge. Peptides 11 to 21 feature the same sequence as the proceeding analog with the subsequent modification depicted in parentheses, with the exception of peptide 20, which was designed from parent peptide 18. All sequences are found in fig. S1.

No.AnalogGLP-1RGIPRGCGR
EC50 (nM)SDRelative
GLP-1 %
EC50 (nM)SDRelative
GIP %
EC50 (nM)SDRelative
glucagon %
1GLP-10.0280.0021001513.82578.95002449.288106.4600
2Exendin-40.0040.0016212.9520.8411186.14716.6770
3GLP-1 (Aib2 E16 Cex K40)0.0170.0031581200.336100.00302000.659500.0000
4Liraglutide0.0110.00324978.6577.6200172.92922.5610
5GIP1567.01265.78000.0200.004100417.48010.3700
6GIP (Aib2)3527.099310.81000.0160.0011261459.502123.8000
7GIP (Aib2 Cex K40-C16 acyl)6.3302.69000.0120.0011682.9200.8401
8Glucagon3.1000.49411538.109329.02000.0320.006100
9Glucagon
(Aib2 K10-γEγE-C16 acyl Aib20)
0.4790.068622.6506.10000.0050.001616
10Glucagon
(E16 Q17 A18 K20 E21 I23 A24)-NH2
0.0220.0021266.2581.27800.0300.009104
11Peptide 10 (I17 H18 Q19)-NH20.1400.019205.5301.09900.1500.02221
12Peptide 11
(Q17 A18 A19 Cex)-NH2
0.0200.00213814.5572.24100.0600.00353
13Peptide 12 (Y1)-NH20.1200.008233.0540.66310.0600.00353
14Peptide 13
(V23 N24 L27 A28)-NH2
0.0400.001690.5570.06940.0400.00279
15Peptide 14
(Aib2 I12)-NH2
0.0100.0012760.1760.019110.1900.03917
16Peptide 15 (Aib20 (−)lactam C40)-NH20.0240.0091150.0400.007503.4570.6991
17Peptide 16 (E3 K16)-NH20.0120.0022300.0030.00167358.9478.2840
18Peptide 17 (K40)-NH20.0160.0021770.0100.0022026.9081.5860
19Peptide 18
(K40-C16 acyl)-NH2
0.0050.0015090.0030.0016911.2860.1032
20Peptide 18
(C24)-NH2
0.0240.0041170.0060.00133712.1921.4330
21Peptide 20 (C24-40 kD PEG)-NH20.3230.02890.1940.04310358.50044.7700