NEW DIHYDROFOLATE REDUCTASE AND MODIFIED DIHYDROFOLATE REDUCTASE GENE

摘要

PURPOSE: To obtain the subject enzyme capable of suppressing inactivation of the enzyme and providing a homogenous immobilized enzyme having high activity by transducing an amino acid sequence containing plural amino acid residues having cysteine residue as the carboxyl terminal into the carboxyl terminal side of an enzymic protein. ;CONSTITUTION: A genetic DNA capable of coding a dihydrofolate reductase is used to replace the sequence part capable of coding the carboxyl terminal side of this enzymic protein with a chemical synthetic DNA. Thereby, a genetic DNA capable of coding a modified enzymic protein in which a short amino acid sequence is transduced so that the carboxyl terminal may be the cysteine residue is prepared. The resultant genetic DNA is then integrated into a vector such as a plasmid for expression to construct an expression vector, which is subsequently transduced into a host such as Escherichia coli and expressed. The obtained modified enzymic protein can be separated and purified from the host microbial cell to afford a new dihydrofolate reductase, having an amino acid sequence expressed by the formula, capable of efficiently producing a homogenous immobilized enzyme having high activity and utilizable for producing various useful substances.;COPYRIGHT: (C)1993,JPO&Japio