Fig. 5

a ESI–MS spectrum of rFab from bioreactor 1 under non-reduced condition. The MW profile of rFab was observed at 48,813 Da, and the MW profile of oxidized rFab with two oxidations was detected at 48,844 Da with 37% peak intensity percentage (Table 2). b ESI–MS spectrum of rFab from bioreactor 1 under TCEP-reduced condition. The MW at 23,587 Da matched with the light-chain theoretical MW with two disulfide bonds, and the MW at 25,229 Da matched with the heavy chain theoretical MW with two disulfide bonds. c ESI–MS spectrum of rFab from bioreactor 4 under non-reduced condition. The MW profile of rFab was observed at 48,813 Da, and no oxidized rFab was detected from bioreactor 4. d ESI–MS spectrum of rFab from bioreactor 4 under TCEP-reduced condition. The MW at 23,587 Da matched with the light-chain theoretical MW with two disulfide bonds, and the MW at 25,229 Da matched with the heavy chain theoretical MW with two disulfide bonds. e ESI–MS spectrum of rFab from bioreactor 8 under non-reduced condition. The MW profile of rFab was observed at 48,813 Da, and no oxidized rFab was detected from bioreactor 8. f ESI–MS spectrum of rFab from bioreactor 8 under TCEP-reduced condition. The MW at 23,587 Da matched with the light-chain theoretical MW with two disulfide bonds, and the MW at 25,229 Da matched with the heavy chain theoretical MW with two disulfide bonds