Akiko Nakazawa

A new D-stereospecific amino acid amidase from Ochrobactrum anthropi.

A new D-stereospecific amino acid amidase has been partially purified from Ochrobactrum anthropi SCRC SV3, which had been isolated and selected from soil. The Mr of the enzyme was estimated to be about 38,000, and its isoelectric point was 5.3. The enzyme catalyzes the stereospecific hydrolysis of D-amino acid amide to yield D-amino acid and ammonia. The major substrates included D-phenylalanine amide, D-tyrosine amide, D-tryptophan amide, D-leucine amide, and D-alanine amide.

First stereoselective synthesis of D-amino acid N-alkyl amide catalyzed by D-aminopeptidase

Abstract The first stereoselective synthesis of D-amino acid N-alkyl amides was achieved by the use of D-aminopeptidase from Ochrobactrum anthropi . The enzyme immobilized by urethane prepolymer PU-6 catalyzed aminolysis reaction of racemic amino acid esters in organic solvents.

Synthesis of D-Alanine Oligopeptides Catalyzed by D-Aminopeptidase in Non-Aqueous Media

Synthesis of D-alanine oligopeptides from D-alanine methylester hydrochloride has been demonstrated by use of immobilized D-aminopeptidase from Ochrobactrum anthropi (Achromobacter sp.) in non-aqueous media. D-Alanine dimer and trimer were obtained in 56% and 6% yield, respectively, when 250 mM of the substrate was incubated for 3 hours with urethane-prepolymer immobilized D-aminopeptidase (1.5 U/ml) and 3 equivalents of triethylamine in water-saturated toluene. The kcat of this reaction was calculated to be 19,500 (min−1), which is several ten thousand times greater than that of the known enzymatic syntheses of amino acid oligomers.