Fig. 2. The biochemical properties of the constrained peptides. (A) Dealkylation of model peptide 1-Ia (1 mM) in the presence of PyS (10 mM) in PBS (pH = 7.4) at 37 °C for 48 hours. HPLC traces of the time-dependent conversion between peptide 1-Ia and its conjugated product 1-Ia-R. (B) The kinetics of peptide dealkylation reactions with different reductants under the same reaction conditions as indicated in (A). (C) Cellular uptake of the cyclic and linear peptides in A2780 cells treated with 10 μM FAM-labeled peptides for 4 hours. All cells were incubated with 0.05% trypan blue for 3 minutes before further analysis.