Phenylalanine ammonialyase mutant derived from anabaena variabilis as well as preparation method and application of phenylalanine ammonialyase mutant

The invention provides a phenylalanine ammonialyase mutant derived from anabaena variabilis as well as a preparation method and application of the phenylalanine ammonialyase mutant, and belongs to the technical field of biological medicines. The mutant is obtained by carrying out at least one of the following point mutations on an L4 site in phenylalanine ammonialyase (AvPAL) derived from anabaena variabilis, the L4 site is mutated into any one of the following amino acids: glutamine, threonine, serine, asparagine, aspartic acid, valine, methionine and lysine. Experimental results show that compared with wild-type phenylalanine ammonia lyase, the prepared mutant has higher enzyme catalytic activity, meanwhile, the soluble expression is greatly improved, and a new means is provided for preparing drugs for treating phenylketonuria. 本发明提供了一种多变鱼腥藻来源的苯丙氨酸解氨酶突变体及其制备方法和应用，属于生物医药技术领域。所述突变体是对来源于多变鱼腥藻的苯丙氨酸解氨酶(AvPAL)中L4位点进行以下至少一种点突变获得；所述L4位点突变为以下任意一种氨基酸：谷氨酰胺、苏氨酸、丝氨酸、天冬酰胺、天冬氨酸、缬氨酸、蛋氨酸和赖氨酸。实验结果表明，与野生型苯丙氨酸解氨酶相比，制备的突变体获得了更高