Fig. 3: Sulphostin shows promising selectivity within FP target proteins.
From: Sulphostin-inspired N-phosphonopiperidones as selective covalent DPP8 and DPP9 inhibitors
a Overview of a competitive ABPP workflow. A cell lysate is pre-incubated with an inhibitor, composed of a leaving group (LG) and a reactive group (RG), followed by a labeling reaction with a probe that covalently binds target proteins via its RG, which can be either an ABP such as FP or an alkyne-tagged ligand. After click attachment of a biotin moiety, labeled proteins are enriched via solid support, tryptic digested on-bead, and subsequently identified via LC-MS/MS analysis. b Cell lysates were treated with 50 µM Sulphostin or DMSO vehicle control prior to treatment with the ABP FP. ABPP of SHs without (FC plotted on x-axis) or after pre-treatment with 50 µM Sulphostin (competition experiment, FC plotted on y-axis) with 2 µM ≡FP after click chemistry (n = 4 biologically independent samples). Dashed lines indicate the FC ≥ 2 ( ≡FP/DMSO) or FC ≤ -2 (Sulphostin/≡FP) threshold. Black symbols indicate identified protein groups, red symbols highlight serine hydrolases (SHs). To identify statistically significant hits from the analysis (marked as a triangle or square), p-value ≤ 0.01 (two-sided Student’s t-test, permutation-based FDR with 250 randomizations and FDR = 0.05) was applied. Source data are provided as a Source Data file.
