Lysis procedure GSH [µM] MPER lysis buffer, room temperature 2.8 5% TFA, -18°C 1.7 5% MPA, -18°C 0.9 0.5% picric acid, -18°C 10.3

Table 3: Amount of extracted GSH by each of the lysis procedures. RSD values were below 15% (N=3).