Figure 2.

Analytical and preparative-scale synthesis of β-hydroxy-α-amino acids by ObiH. Reactions were performed using 20 mM aldehyde, 100 mM l-Thr, 50 mM Tris pH 8.5 and 1–2% ObiH wet whole cells, with 4% (v/v) MeOH as co-solvent. Preparative scale reactions were incubated at 37 °C for 18 h before quenching with 1 volume equivalent of MeCN, followed by freeze-thaw and centrifugation to remove cell debris. Purification was achieved using a Biotage purification system via reverse-phase chromatography. Yields are reported as isolated product mass after lyophilization. ¹H NMR hydration analysis was used to correct yield values for excess water. Analytical scale product yields determined by UPLC-PDA-MS following derivatization with Marfey’s reagent.