Theanine synthetase gene and method for preparing theanine

Abstract

The invention discloses a theanine synthetase gene and a method for preparing theanine. The total length of a synthetase gene cDNA is 2,886 bp, the length of a reading frame is 2,532 bp, and a gene cDNA sequence is as shown in SEQ ID No.1. The theanine synthetase gene can be used for synthesizing and preparing theanine. The method particularly comprises the steps that 1, a target gene, as shown in SEQ ID No.1, of a nucleotide sequence is obtained; 2, pMAL-c5x servers as a vector, the target gene is connected to the vector, a recombinant vector is obtained, and escherichia coli is led into the recombinant vector; 3, the escherichia coli led into the recombinant vector is subjected to induced expression, induced protein is produced, substrates of sodium glutamate and ethylamine hydrochloride are added, cultivation is conducted continuously for 12 h, products in a culture medium are collected and then subjected to centrifugation, supernatant is taken, filtration is conducted with an aqueous phase filter membrane of 0.22 micrometers, and a synthesized theanine solution is obtained. Due to the fact that the synthesizing method is similar to a synthetic reaction taking place in a plant body, the synthesizing method has the advantages of being few in side reaction, simple in product refining step and the like.

Description

technical field [0001] The invention relates to the field of biology, in particular to a theanine synthetase isolated from tea trees and a method for preparing theanine by using the same. Background technique [0002] Theanine (N-ethyl-γ-L-glutamine) is a characteristic non-protein amino acid of tea tree that was first isolated and named from green tea by Japanese scholar Sakato in 1949. Theanine has a caramel aroma and a refreshing taste similar to monosodium glutamate, which can relieve the bitterness, increase the sweetness of the tea soup, and improve the taste. The content of theanine is positively correlated with the quality and grade of tea, and the correlation coefficient is as high as 0.787-0.876, which largely affects the taste quality of green tea. More importantly, a large number of studies have shown that theanine has health care functions and pharmacological effects, such as neuroprotection, relaxation and sedation, excitation and antagonism, sleep improvement...

AI Technical Summary

Problems solved by technology

Among them, the cost of extracting theanine from tea leaves is high; although tissue culture can moderately increase the content of theanine, this method has disadvantages such as cumbersome operation steps, long cultivation period, large space occupation, and high facility cost. It cannot be popularized and applied; the yield of theanine synthesized by chemical method is low, the separation and refining process of the synthesized product is compl

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