Jiangnan University

Hangyu Jiang

Tao Zhang

Bo Jiang

Ming Miao

Wanmeng Mu

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.

Genetically engineered arginine deiminase modified by site-directed mutagenesis

An arginine deiminase mutant with improved enzyme activity and temperature stability and application thereof were provided, belonging to the technical field of genetic engineering and enzyme engineering. The arginine deiminase mutant is proline, namely Gly292 Pro, mutated from glycine near an enzyme active center. A wild-type arginine deiminase arcA coding gene is molecularly modified by a site-directed mutation technique to obtain a mutant enzyme ADIG292P, which has glycine at position 292 of an amino acid sequence of the wild type arginine deiminase mutated to proline. The arginine deiminase, modified by site-directed mutation, of the present invention has 1.5 times of increase in enzyme activity and 5.43 times of increase in half-life period at 40&#xb0; C. compared with the wild-type enzyme, which solves the problems of low catalytic ability and temperature stability during the catalytic synthesis of citrulline using arginine deiminase, and lays a foundation for industrial production of efficient synthesis of citrulline and medication application.

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Wuxi, China

Hangyu Jiang