NH2-terminal sequence analysis and mass spectrometry of CD26/DPP IV–treated chemokines
| Chemokine . | NH2-terminal sequence* . | Reduction inMr . | ||
|---|---|---|---|---|
| Untreated . | CD26/DPP IV–treated . | Theoretical . | Observed† . | |
| Met-IP-10 | MVPLSRTVRCTC | MVPLSRTVRCTC | 0 | 0 |
| IP-10 | VPLSRTVRCTC | LSRTVRCTC | 196.25 | 196.9 ± 0.4 |
| Mig | TPVVRKGRCSC | VVRKGRCSC | 198.22 | 197.7 ± 0.4 |
| I-TAC | FPMFKRGRCLC | MFKRGRCLC | 244.29 | 243.9 ± 0.3 |
| Chemokine . | NH2-terminal sequence* . | Reduction inMr . | ||
|---|---|---|---|---|
| Untreated . | CD26/DPP IV–treated . | Theoretical . | Observed† . | |
| Met-IP-10 | MVPLSRTVRCTC | MVPLSRTVRCTC | 0 | 0 |
| IP-10 | VPLSRTVRCTC | LSRTVRCTC | 196.25 | 196.9 ± 0.4 |
| Mig | TPVVRKGRCSC | VVRKGRCSC | 198.22 | 197.7 ± 0.4 |
| I-TAC | FPMFKRGRCLC | MFKRGRCLC | 244.29 | 243.9 ± 0.3 |
Single-letter amino acid abbreviations used.
The NH2-terminal sequence of untreated and CD26/DPP IV–treated (18-hour incubation) chemokines was determined by automated Edman degradation.
The average (± SD) difference between theMr of intact and truncated CXCR3 ligands was calculated from mass measurements on 4 different incubations (between 2 and 30 minutes) with CD26/DPP IV (25 U/L).