Mutated arginine deiminase as well as preparation method and application thereof

The invention discloses a mutated arginine deiminase as well as a preparation method and an application thereof. Amino acids in one or more sites of K137A, F198W, V230A, R257L and A260D of arginine deiminase mutate, and the mutated arginine deiminase is improved in activity significantly, can be used for catalyzing L-arginine to produce L-citrulline and can achieve the conversion rate of more than 95%. The mutated arginine deiminase is prepared by adopting an error-prone PCR (polymerase chain reaction) system.