Abstract:

Alkoxy-L-serines are useful for peptide syntheses. The demand for alkoxy-L-serines in the pharmaceutical industries continues to increase because of their multiple physiological effects. In this research, an improved method for alkoxy-L-serines synthesis is reported. A series of substrates, DL-β-alkoxy-α-amino propionamides, was used for the synthesis of alkoxy-serines catalyzed by Escherichia coli cells with peptidase B(PepB) activity. The results show that PepB has a high resolution activity with DL-β-alkoxy-α-amino propionamides as substrate. Reaction conditions were optimized, i.e., DL-β-methoxy-α-amino propionamide as substrate at pH=9.0, 40 ℃ and 14 h, and the optimal reaction concentration is 400 mmol/L. The results also show that divalent metal cations exhibit different effects on the PepB activity, for example, Zn²⁺ and Cu²⁺ can obviously inhibit the activity of PepB, whereas Co²⁺, Ca²⁺, Mn²⁺ and Mg²⁺ at low concentrations can activate PepB. This research provides access to enantiomerically enriched and valuable alkoxy-L-serines from a simple amino-amide racemate.

Key words: Alkoxy-serine, DL-β-Alkoxy-α-amino propionamide, Enzymatic resolution, Peptidase B