Hepes

L-glutathione (GSH) was obtained from Sigma Aldrich (G4251), L-ergothioneine from Santa Cruz Biotechnology (sc-200814), L-cysteine from Fisher Biotech (BP376-100), L-hercynine from Toronto Research Chemicals (H288900), L-histidine from Sigma Aldrich (H8000), choline chloride from Sigma Aldrich (C1879), glycine-betaine from Sigma Aldrich (B3501), ectoine from Sigma Aldrich (81619), proline-betaine from VWR (TCS0358), L-carnitine from Sigma Aldrich (C0283), and dimethypropiothetin hydrochloride from Sigma Aldrich (80828). These chemicals were used without further purification. Other chemicals include IPTG from GoldBio (2481C100), TCEP from Chem-Impex (00194), dithiothreitol from Chem-Impex (00127), Tris-HCl from MP Biomedicals (816100), HEPES from Chem-Impex (00174), EDTA from VWR Chemicals (BDH9232), NaCl from VWR Chemicals (BDH9286), Imidazole from Chem-Impex (00418), Sypro Orange from Sigma (S5692), and monobromobimane (mBBr) from Sigma (B4380). BHI broth was obtained from BD (37500, lot 1159859) while Luria broth was obtained from Fisher Bioreagent (BP9723). Milli-Q water was used to make all solutions.

The prototype UMP-Glo assay kit was a generous gift from Promega. HEPES (99.9%) was obtained from Chem-Impex International. NaCl (>99%) and glycerol (>99%) were from Research Products International. Triton X-100 and DMSO (99.9%) were from Sigma-Aldrich, MgCl₂.6H₂O (100%) was from Mallinckrodt Chemicals. DDM (>99%) was purchased from Anatrace. 96-well half-area white plates were obtained from Corning. Ni-NTA resin was from Thermo Fisher. All other chemicals and bio-reagents were purchased at the purest grade available.