Figure 3.
Purified EL-4-adapted 20S have a reduced degradation rate compared with EL-4 20S. Degradation products of Sendai NP317–338 peptide, incubated with purified EL-4 or EL-4-adapted 20S for specified times, were analyzed by reverse-phase HPLC and on-line MS (liquid chromatography-MS). (A) Reverse-phase HPLC chromatograms illustrate the formation of degradation products (boxes 1–5) generated by the EL-4 20S over indicated time intervals. The initial 21 residue peptide (S) and irrelevant peaks (*) are indicated. Mass spectra of each fragment are shown on the left. (B) The fragmentation products generated by the 20S from EL-4 (filled bars) and adapted cells (open bars) were identified by molecular mass in TIC chromatograms (data not shown) and quantified by their UV peak integration area.