Table 1.
Purity of peptides determined by LC/MS
| Entry | Name | Sequence | HPLC puritya (%) | Calcd massb (g mol−1) | Obsd massb (g mol−1) |
|---|---|---|---|---|---|
| 1 | [Ile6,His5]-AII | DRVYHIPF | 98 | 1045.5 | 1046 |
| 2 | des-Ile5,His6-AII | DRVYPF | 98 | 795.4 | 796 |
| 3 | des-Asp1,Val3,Ile5,His6-AII | RYPF | 99 | 581.3 | 582 |
| 4 | [Ile4,His3]-des-Asp1,Val3-AII | RYHIPF | 98 | 831.4 | 833 |
| 5 | des-Asp1,Arg2,Val3,Ile5-AII | YHPF | 99 | 562.2 | 563 |
| 6 | des-Asp1,Arg2,Tyr4,His6-AII | VIPF | 99 | 474.3 | 475 |
| 7 | [2-Nal1]- des-Asp1,Arg2,Tyr4,His6-AII | (2-Nal)-IPF | 97 | 572.3 | 574 |
| 8 | [2-Nal2]- des-Asp1,Arg2,Tyr4,His6-AII | V-(2-Nal)-PF | 99 | 558.3 | 559 |
| 9 | [2-Nal3]- des-Asp1,Arg2,Tyr4,His6-AII | VI-(2-Nal)-F | 97 | 574.3 | 575 |
| 10 | [2-Nal4]- des-Asp1,Arg2,Tyr4,His6-AII | VIP-(2-Nal) | 98 | 523.3 | 524 |
a HPLC profiles were obtained under the following conditions: Column Supelcosil C18 (4.6 × 150 mm), 60 Å, 5 μm; Solvent System: A (0.1 % TFA/H2O) and B (0.1 % TFA in 60 % ACN/H2O); Gradient: 5–95 % B in 30 min; Flow: 1.0 mL/min; λ = 220 nm; Injection Volume: 50 μL and sample concentration: 1.0 mg/mL
bThe masses were determined by LC/ESI–MS using a Micromass instrument (model ZMD) coupled to a Waters Alliance (model 2690) system. Mass measurements were performed in a positive mode with the following parameters: mass range between 300 and 2000 m/z; nitrogen gas flow: 4.1 L/h; capillary: 2.3 kV; cone voltage: 32 V; extractor: 8 V; source heater: 100 °C; solvent heater: 400 °C; ion energy: 1.0 V and multiplier: 800 V