Method for efficiently catalyzing and synthesizing L-carnosine in whole cell

Abstract

The invention discloses a method for efficiently catalyzing and synthesizing L-carnosine in a whole cell. The method comprises the following steps of 1) constructing a recombinant vector containing anamino acid fatty acyltransferase gene with a nucleotide sequence shown in SEQ ID NO.1, wherein the amino acid sequence encoded by the gene is shown in SEQ ID NO. 2; 2) transferring a gene with a nucleotide sequence shown in SEQ ID NO.1 to bacterium coli to obtain recombinant bacterium coli; 3) dissolving a substrate beta-alanine methyl ester and L-histidine in a buffer solution, wherein the pH is7.5-9.5; 4) adding the recombinant bacterium coli to the buffer solution for reaction, wherein the reaction temperature is 25-42 DEG C. A recombinant plasmid and recombinant engineered bacteria of the gene directly catalyze and synthesize the L-carnosine in the catalytic system, thereby improving the conversion rate of the L-carnosine, and the problems of the complicated separation and purification of an enzyme and the high cost of an aminopeptidase catalytic process are solved.

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 [J]. 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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