Table 3.
Identification of chlorinated and butylated tyrosines and an oxidized tryptophan in peptides of ROS-treated rabbit hemopexin using LC-MS/MS
These modified amino acids in five peptides were unambiguously detected and identified using MASCOT (see supplemental data). HPX/ROS ratios were 1:10 HOCl (VWoxVYTSEK, FNPVSGEVPPGYClPLDVR, and GGYTLVNGYClPK); 1:2.5 t-BuOOH (YYtBuCFQGNQFLR); and 1:1 t-BuOOH (DYtBuFLSCPGR). Superscripts indicate residues modified by oxidation (ox), t-butylation (t-Bu), or mono-chlorination (Cl).
| HPX species | NCBI gi number | Peptide sequence | COM site | Charge (+) | Mascot ions score |
|---|---|---|---|---|---|
| Rabbit | 130500366 | 118VWoxVYTSEK125 | 119 | 2 | 39.3 |
| Rabbit | 130500366 | 200YYt-BuCFQGNQFLR210 | 201 | 2 | 51.1 |
| Rabbit | 130500366 | 211FNPVSGEVPPGYClPLDVR227 | 222 | 2 | 69.8 |
| Rabbit | 130500366 | 228DYt-BuFLSCPGR236 | 229 | 2 | 25.1 |
| Rabbit | 130500366 | 331GGYTLVNGYClPK341 | 339 | 2 | 47.6 |