Figure 4.

Oxidative modification of identified proteins in planta upon H₂O₂ treatment. Transgenic plants expressing the protein of interest fused with the FLAG tag were vacuum infiltrated with either water (mock) or 5 mM H₂O₂. For analysis of AtCIAPIN1, eEF1α, and AtPTP1, free thiols in the total protein were labeled with BIAM during protein extraction. For analysis of AtNAP1;1 and AtPDIL1-1, free thiols in the samples were first alkylated by IAM. Samples were then treated with DTT and newly generated free thiols were labeled by BIAM. After that, FLAG-tagged protein from each sample was affinity purified, separated by SDS-PAGE, and detected by HRP-Conjugated Streptavidin (to determine the amount of BIAM attached to the FLAG-tagged protein) or by the anti-FLAG M2 antibody (to determine the amount of the total recombinant protein).