Auto flex max maldi tof

SCP1 WT (50 μM) and SCP1 C181A mutant in activity buffer at pH 7.6 (with 5 μM or 500 μM BME) were treated with 500 μM of GR-28 (final 1% DMSO), and control samples were treated with 1% DMSO. The samples were incubated overnight at RT. The pNPP activity was tested the next day by taking a sample from each tube. The samples were then desalted using Ziptip C18 resins (Sigma-Aldrich) following standard protocols. Mass spectrometric analysis of SCP1 treated with GR-28 or DMSO was performed using an Auto-flex Max MALDI-TOF (Bruker Corporation, Billerica, MA) with a 1:1 DHB matrix (ThermoFisher, Waltham, MA).

The PNH was prepared based on a previously reported method with a modification.^[17] In brief, 30% aa, 10% gelatin, 1% aa–PEG–NHS, 0.1% BIS, and 1% HMPP (w/w) were dissolved in distilled water under magnetic stirring at 37 °C for 2 h. The pregel solution was then exposed to the UV light for 30 min to form the wet adhesive PNH, which was further totally dried in the hood for 24 h to obtain the dry PNH.^[1] HNMR (Bruker 600 MHz) and mass spectrum (Bruker autoflex maX MALDI‐TOF) was carried out to measure the molecular weight of aa–PEG–NHS. FTIR spectrometer (Thermo Fisher, IN10) was used to obtain spectra to determine the chemical functional groups of PNH. GPC (Agilent PL‐GPC50) and TG (NETZSCH STA 449 F5) were performed to determine the molecular weight and thermal stability of the PNH.