Synthesis of D-phenylalanine oligopeptides catalyzed by alkaline D-peptidase from Bacillus cereus DF4-B

Synthesis of D-phenylalanine oligopeptides from D-phenylalanine methylester has been demonstrated by use of alkaline D-peptidase (ADP) from Bacillus cereus. An expression plasmid pKADP was constructed by placing the PCR-amplified ADP gene (adp) under the tac promoter of pKK223-3. Oligomerization of D-phenylalanine methylester by use of the purified ADP from the transformant Escherichia coli was investigated under several conditions. D-Phenylalanine dimer, (D-Phe),, and trimer, (D-Phe),, were produced in 25.4% and 8.6% yield, respectively, when 50 mM of the substrate was incubated for 8 h with ADP (2.0 U/ml and 0.4 U/ml, respectively) in 100 mM triethylamine-HCl (pH 11.5). Addition of dimethylsulfoxide to the reaction mixture resulted in the production of tetramer, (D-Phe), in 6.7% yield with the decrease of the (D-Phe), and (D-Phe), production. This is the first study on the synthesis of D-phenylalanine oligomers by use of a D-stereospecific endopeptidase. (C) 1999 Elsevier Science B.V. All rights reserved.