Genetically Engineered Arginine Deiminase Modified by Site-Directed Mutagenesis

摘要

A genetically engineered arginine deiminase reconstructed by site-directed mutagenesis belongs to the technical field of genetic engineering technology. Its amino acid sequence is shown as SEQ ID No. 1. In the amino acid sequence of the arginine deiminase reconstructed by site-directed mutagenesis, glycine at position 264 is mutated to proline, compared to an amino acid sequence of native arginine deiminase. Compared with wild type enzyme, the effective pH range effect of the mutated arginine deiminase according to the present invention is broadened to a certain extent, and especially a good enzyme activity is achieved at physiological pH 7.4. With the broadening of the effective pH effect range, the mutant enzyme still has higher stability under the condition of pH 5.5-7.5. Therefore, the problem that the arginine deiminase generally is low in enzymatic activity and short in half-life in vivo under physiological conditions in clinical application for tumor therapy is solved, and a good condition for using the enzyme and an encoding gene thereof for clinical treatment is created.