Fig. 2.

LC-MS/MS analysis of VEGF₁₆₅a-TMR digested with multiple proteases. (a) Peptide coverage achieved by digestion with LysC, GluC and Trypsin/LysC proteases. The N terminal cysteine is marked in red. None of the other 16 residues presented in the VEGF₁₆₅a protomer were labeled. Protein identity was confirmed by searching the MS/MS spectra using the Mascot search engine (Matrix Science Inc, Boston, USA) against a human database (SwissProt). The highest scoring hit was the VEGF sequence. (b) LC-MS/MS analysis of the peptide containing the N terminal cysteine (CDNAPMAEGGGQNHHEVVK) derived from VEGF₁₆₅a and VEGF₁₆₅a- that were purified in the same manner and digested with LysC protease. Retention times and mono-isotopic masses are given in Table 1. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)