| 摘要 |
PURPOSE: Mutated N-carbamoylase with improved acid-stability is provided, thereby effectively and cheaply producing synthetic D-amino acids without addition of DTT(dithiothreitol). CONSTITUTION: A gene encoding mutated N-carbamoylase has the nucleotide sequence of SEQ ID NO: 4, 12, 13 or 14, wherein the mutated N-carbamoylase is NC23, Gln23Leu, Val40AAla or Gly75Ser, respectively. A recombinant plasmid pNC23 contains the gene of SEQ ID NO: 4. A transformed Escherichia coli NC23(JM109/pTrc99a/NC23)(KCTC 10164BP) is produced by transforming with the recombinant plasmid pNC23. A method for producing the mutated N-carbamoylase comprises culturing the transformed Escherichia coli NC23(JM109/pTrc99a/NC23)(KCTC 10164BP). A method for producing synthetic D-amino acid comprises reacting the mutated N-carbamoylase with N-carbamoyl-D-amino acid, wherein the N-carbamoyl-D-amino acid is N-carbamoyl-D-para-hydroxyphenylglycine, N-carbamoyl-D-valine or N-carbamoyl-D-serine; and the synthetic D-amino acid is D-para-hydroxyphenylglycine, D-valine or D-serine.
|
