| 摘要 |
PURPOSE:To efficiently produce L-dopa or L-tyrosine, by introducing beta-tyrosinase gene separated from a microorganism having beta-tyrosinase activity into a prokaryotic cell and using the resultant transformed cell. CONSTITUTION:A recombinant DNA prepared by using a chromosomic DNA extracted from a beta-tyrosinase holding strain, e.g. Erwinia herbicola ATCC 21433, is introduced into an Escherichia coli HB101 strain having no enzymic activity and transformed to give a beta-tyrosinase gene. A fragment obtained by partially cleaving DNA extracted from the transformant with a restriction enzyme is linked to a vector and introduced into the HB101 strain to afford a pSI2073 and 2074 plasmid having a relatively small linked DNA fragment. A DNA fragment obtained by cleaving the former with PstI is linked to a plasmid pUC18 to provide a small-sized plasmid having beta-tyrosinase gene having 1.7kb number of base pairs and cleavage part of EcoRI. The aimed L-dopa or L-tyrosine can be efficiently produced by using the transformant strain holding the above-mentioned plasmid. |
