Fig. 5.

ZBM-H inhibited oxidation of GRP78 caused by HOCl to enhance its activity. a Mass spectrometry analysis showed that ZBM-H inhibited GRP78 oxidation modification at lysine 352 and 353. b Example of MS/MS spectra of the lysine-oxidized peptide VLEDSDLK[Oxi]K[Oxi]. The tryptic digest of purified GRP78 from cells treated with ZBM-H or DMSO was analyzed with the use of LC–MS/MS. c, d Western blot analysis of phosphorylation of AMPKα (Thr172) in A549 cells transfected with his₆-GRP78-wt (wild type), his₆-GRP78-mut2 (K353A) mutant and his₆-GRP78-mut1 (K352A) mutant plasmids and treated with ZBM-H. e–g ATPase activity of GRP78-wt, GRP78-mut1 and GRP78-mut2 incubated with ZBM-H at indicated concentrations. Data are presented as the mean ± SEM, NS p > 0.05, *p < 0.05, **p < 0.01, n = 3