Mutant enzyme, use thereof and process for preparing tripeptide by using enzymatic method

Abstract

The present invention relates to the technical field of biochemistry. Disclosed are a mutant enzyme, the use thereof and a process for preparing a tripeptide by using an enzymatic method. The mutant enzyme comprises: glycine and L-histidine ligase GHS, and tripeptide ligase HKS; or a fusion enzyme of the two. Glycine and L-histidine ligase activity is achieved by means of modifying an Lal enzyme, so as to obtain the GHS enzyme; and the ability for synthesizing dipeptide glycine-L-histidine and L-lysine is achieved by means of using a gshB enzyme, so as to obtain the HKS enzyme. On this basis, the GHS enzyme is further fused with the HKS enzyme by means of using a polypeptide chain, and then a bifunctional enzyme GHKS that links glycine, L-histidine and L-lysine in one step can be constructed, so that a tripeptide is conveniently prepared with a high yield. With regard to the large amount of ATP required in an enzymatic reaction, polyphosphate kinase can be used for cyclic regeneration, such that the amount of ATP is greatly reduced.

Dependencies are inferred from the claim text.