Spectrospin 300 mhz spectrometer

Intracellular phospho-STAT5 (pSTAT5) was measured using a BD LSR Fortessa Flow cytometer (BD Biosciences, San Diego, CA, USA). NMR spectra were recorded on a Bruker SPECTROSPIN 300 MHz spectrometer (Bruker Corporation, Billerica, MA, USA). For the pSTAT5 assay measuring TSLP inhibitory activity, recombinant human TSLP was purchased from R&D Systems (Minneapolis, MN, USA) and BD Cytofix/Cytoperm and Alexa Fluor 647 mouse anti-STAT5 (pY694) were purchased from BD Biosciences (San Diego, CA, USA). For the ELISA assay to assess hTSLP–hTSLPR interaction, Ni-NTA HisSorb plates were purchased from Qiagen (Hilden, Germany), and monoclonal anti-FLAG antibody conjugated to HRP and o-phenylenediamine dihydrochloride were purchased from Sigma-Aldrich Co. (St. Louis, MO, USA). Iscove’s modified Dulbecco’s medium (IMDM) and fetal bovine serum (FBS) were purchased from Hyclone Laboratories Inc. (Logan, UT, USA). Penicillin-streptomycin was purchased from Gibco Industries Inc. (Auckland, NZ, USA).

Medium pressure liquid chromatography (MPLC) was conducted using a Biotage Isolera (Biotage AB, Uppsala, Sweden). One system equipped with a high performance flash chromatography (HPFC) pump, a variable dual-wavelength detector, and a collector. NMR spectra were acquired using a Bruker SPECTROSPIN 300 MHz spectrometer (Bruker Corporation, Billerica, MA, USA). Methanol-d₄, an NMR solvent, was purchased from Cambridge Isotope Laboratories, Inc. Acetonitrile (ACN), water, and methanol (MeOH) of chromatographic grade were purchased from ThermoFisher Scientific Korea Ltd. (Seoul, Republic of Korea). L-tyrosine, mushroom tyrosinase, kojic acid, and formic acid were purchased from Sigma–Aldrich Co (St. Louis, MO, USA).