Figure 4

OaAEP4 is tolerant to acetone, N-N-dimethylformamide and methanol. Recombinant OaAEP4 (0.104 µM) was incubated with the R1 peptide (KL–NGL variant) (280 µM) at pH 5 for 60 min in the presence of increasing concentrations of organic solvents. The assays were conducted in activity buffer (50 mM sodium acetate buffer, pH 5.0, 0.5 mM NaCl, 1 mM EDTA, 0.5 mM TCEP) at room temperature. The products were assessed by MALDI-MS. The proportion of cyclic product was determined relative to all peaks attributed to the processed or unprocessed target peptide. Reactions were stopped by heating at 70 °C for 5 min. The average of two technical replicates is shown and error bars report the range.