Whole-cell one-step method for synthesizing L-carnosine

Abstract

The present invention discloses a whole-cell one-step method for synthesizing L-carnosine. The whole-cell one-step method comprises the following steps: 1) a recombinant vector is constructed, the recombinant vector contains an amino acid fatty acyltransferase gene having a nucleotide sequence shown in SEQ ID NO.1, and an amino acid sequence encoded by the gene is shown in SEQ ID NO.2; 2) the genehaving the nucleotide sequence shown in the SEQ ID NO.1 is transferred into Escherichia coli to obtain recombinant Escherichia coli; 3) substrates of beta-alanine methyl ester and L-histidine are dissolved in a buffer solution, and pH is 7.5-9.5; and 4) the recombinant Escherichia coli is added to the buffer solution for reaction at a reaction temperature of 25-42 DEG C. Recombinant plasmids andrecombinant engineering bacteria of the gene are utilized to directly catalyze synthesis of the L-carnosine in a catalytic system, and the method improves conversion rate of the L-carnosine, and at the same time solves problems of complicated separation and purification of enzymes and high cost of an aminopeptidase catalytic process.

Description

technical field [0001] The invention relates to a method for synthesizing carnosine, in particular to a method for efficiently synthesizing L-carnosine by directly using recombinant Escherichia coli as a whole-cell catalyst, and belongs to the technical field of biological production. Background technique [0002] L-carnosine (β-alanyl-L-histidine) and its analogues (such as homocarnosine and anserine) are natural active dipeptides widely present in the brain, muscle and other important tissues of mammals. Since the discovery of this active peptide for more than 100 years, a large number of studies have found or proved that L-carnosine has significant anti-oxidation, elimination of intracellular free radicals, anti-aging and other activities, and it is clinically used for hypertension, heart disease, etc. adjuvant therapy for disease, senile cataract, ulcer, anti-tumor, and promotion of wound healing. Due to its strong antioxidant activity, low toxic and side effects and va...

AI Technical Summary

Problems solved by technology

However, there is a certain degree of inhibition in the activity of organic relative enzymes, and the solubility of amino acid substrates in organic phases is also low. Various reasons have resulted in very low yields based on aminopeptidase synthesis of L-carnosine (the best result is 3.7g / L, Microbial Biotechnology, 2010, 3(1):74-83.)

In addition, aminopeptidase will form tripeptides, resulting in complex reaction products, difficult extraction and purification, and low yield of L-carnosine (Heck T, V S Makam, J Lutz, et al. Kinetic Analysis of L-Carnosine Formation by β- Aminopeptidases. Advanced Synthesis & Catalysis, 2010, 352(2-3): 407-415.)

Moreover, the cost of preparation and separation by biological enzyme method is high, it is difficult to recycle and reuse, and it is not conducive to large-scale application

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