Table 1.
Compounda | Linker | Mass Spectrumb | HPLCc, tR (min) | ||
---|---|---|---|---|---|
Ion | Calc. | Obsd. | |||
Ac-MSH(4) | - | (M+1)+ | 686.3482 | 686.6389 | 9.75 |
NB297 | No linker | (M+5)5+ | 650.1385 | 650.1376 | 12.37 |
NB298 | (Gly-Pro)1 | (M+6)6+ | 647.4978 | 647.4982 | 12.97 |
NB299 | (Gly-Pro)2 | (M+6)6+ | 724.5349 | 724.5359 | 12.90 |
NB300 | (Gly-Pro)3 | (M+6)6+ | 801.5720 | 801.5709 | 12.86 |
NB301 | β-Ala | (M+6)6+ | 577.4685 | 577.4683 | 12.90 |
NB302 | (β-Ala)2 | (M+6)6+ | 612.9871 | 612.9861 | 12.83 |
NB341 | No linker | (M+5)5+ | 548.0752 | 548.0752 | 12.94 |
NB342 | β-Ala | (M+5)5+ | 590.6974 | 590.6969 | 12.90 |
NB397 | No linker | (M+2)2+ | 689.3679 | 689.3666 | 11.58 |
NB399 | No linker | (M+4)4+ | 578.8050 | 578.8053 | 12.62 |
NB297 to NB302 were synthesized using peptide (A) and NB341 to NB399 were synthesized using peptide (B). NB397 is the monovalent ligand and NB399 is the bivalent ligand.
Maldi-TOF or ESI-MS.
Peptides were eluted with a linear gradient from 0 to 100% acetonitrile containing 0.1%TFA in 30 min at 1mL/min. The purity of all peptides determinec by HPLC was ≥ 95%.