32 results about "Methionine synthetase" patented technology

L-Methionine is produced by culturing a microorganism which is deficient in repressor of L-methionine biosynthesis system and/or enhanced intracellular homoserine transsuccinylase activity is cultured in a medium so that L-methionine should be produced and accumulated in the medium, and collecting the L-methionine from the medium. The microorganism preferably further exhibits reduced intracellular S-adenosylmethionine synthetase activity, L-threonine auxotrophy, enhanced intracellular cystathionine γ-synthase activity and enhanced intracellular aspartokinase-homoserine dehydrogenase II activity. The present invention enables breeding of L-methionine-producing bacteria, and L-methionine production by fermentation.

The invention discloses a recombinant escherichia coli capable of high-yielding L-methionine and an application thereof. The recombinant escherichia coli is constructed according to a method as follows: adopting a CRISPR-Cas9 gene editing technology for respectively replacing L-methionine synthase gene promoters with trc promoters in escherichia coli genomes, introducing a host strain genome and screening, thereby acquiring the recombinant escherichia coli capable of high-yielding L-methionine. The host strain is E.coli W3110 Delta metJ Delta metI/pTrc99A/metA*/yjeH which is constructed by knocking out metJ and metI in escherichia coli E.coli W3110 and then introducing a pTrc99A/metA*/yjeH plasmid. The maximal titer of L-methionine can reach up to 2.8g/L and DAP of by-products is obviouslyreduced to above 60% (reduced from 1g/L to below 0.4g/L).

The present invention relates to a pregestational gene alarm diagnosis kit and its detection method, including DNA extraction liquor for extracting DNA template of testee, PCR mixed liquor for amplifying specific fragment on the genomic DNA of testee, DNA polymerase, PCR product enzyme excision mixed liquor, restriction endonuclease, positive control template of homozygous mutation and coupling pipe for making PCR reaction. The described alarm gene includes N5, N10-methylene tetrahydrofolate reductase and methionine synthetase reductase gene, their mulant sites are respectively 667-cytosine-thymine and 66 adenine-guanine, and their primer sequences respectively are 5'-TGA AGG AGA AGG TGT CTG CGG GA-3', 5'-AGG ACG GTG CGG TGA GAG TG-3', 5'-GCA AAG GCC ATC GCA GAA GAC AT-3' and 5'-GTG AAG ATC TGC AGA AAA TCC ATG TA-3'. It can be used for pregestational diagnosis of that filial generation produces neural tube deform or not.

The invention belongs to the technical field of enzyme engineering, and relates to a S-adenosyl-L-methionine synzyme mutant and a preparation method using the same. The mutant is mutated into a plurality of amino acid sites in wild S-adenosyl-L-methionine synzyme of which the amino acid sequence is shown as SEQID NO.1, and the mutated amino acid sites comprise C9R and K224R. According to the S-adenosyl-L-methionine synzyme mutant and the preparation method using the same, compared with the wild S-adenosyl-L-methionine synzyme, the mutant has higher specific activity and has higher product yield and lower enzyme activity reduction when catalyzing is performed for preparing the S-adenosyl-L-methionine synzyme.

The invention discloses a raltitrexed related substance C with inhibition activity on dihydrofolate reductase and methionine synthetase, a preparation method and application thereof as an impurity control group.

The invention discloses a methionine synthetase mutant, a mutant gene and an application of the methionine synthetase mutant and the mutant gene in preparation of vitamin B12. Overexpressed genetic engineering strains of a methionine synthetase gene and a mutant gene in Sinorhizobium meliloti have greatly-improved vitamin B12 producing capability, scarcely have influence on biomass during fermentation culture and have relatively high application and popularization values.

The invention discloses a method for producing L-5-methyltetrahydrofolate (L-5-MTHF) by a biological method. The method comprises the following steps of knocking out a methionine synthetase gene (metH) in a catabolism pathway in escherichia coli, and introducing a new metabolic pathway for producing the L-5-MTHF to construct an engineering bacterium BL21-WL strain or BL21 (delta metH)-C1T strain for producing the L-5-MTHF. By optimizing fermentation conditions for producing the L-5-MTHF by the constructed engineering bacteria, the maximum dry cell weight yield of the engineering bacteria can reach 445.94 mu g.g <-1>, is increased by 99.71% compared with that before optimization and reaches 10.0 times of that of an original strain, and the maximum dry cell weight yield of the engineering bacteria can reach 1249.11 mu g after being converted into the yield of each liter of culture and is far greater than the yield (119.84 mu g.L <-1>) of the L-5-MTHF which takes E.coli as host bacteria in the current report. It is indicated that the method and the constructed engineering bacteria have great application value and market prospects.

The invention provides a combination product for detecting enzyme activity of thiopurine S-methyltransferase. The combination product contains S-adenosyl-L-methionine or an enzymatic reaction system producing the S-adenosyl-L-methionine, a methyl receptor and S-adenosyl-L-homocysteine hydrolase, wherein the enzymatic reaction system producing the S-adenosyl-L-methionine comprises adenosine triphosphate, methionine and S-adenosyl methionine synthetase. Preferably, the combination product is in the form of kit, wherein each ingredient contained in the combination product is in a separately self-existent reagent state. The combination product can be used on semi-automatic or fully-automatic analyzing detection equipment, the detection sensitivity is high, the specificity is high, and the operation is simple and convenient, so that the combination product can be practically popularized.

The invention discloses a Raltitrexed-related substance F with raltitrexed with dihydrofolate reductase and methionine synthetase inhibitory activity, a preparation method thereof, and an applicationof the Raltitrexed-related substance F as an impurity reference substance.

The invention provides a recombined strain capable of simultaneously compressing glutathione synthetase system and adenosyl methionine synthetase and a method for simultaneously producing glutathione and S-adenosyl methionine at high yield. The recombined strain comprises: fragment capable of exogenously expressing gama-glutamyl cysteine synthetase or glutathione synthetase and fragment capable of exogenously expressing adenosyl methionine synthetase and the strain is capable of expressing glutathione synthetase system and/or adenosyl methionine synthetase, thereby fermenting glutathione and adenosyl methionine. The recombined strain is capable of simultaneously producing glutathione and adenosyl methionine by fermentation at high yield and independently producing glutathione or adenosyl methionine by fermentation.

The invention relates to a genetically engineered bacterium for producing N-acetyl-5-methoxytryptamine as well as a construction method and application of the genetically engineered bacterium. The genetically engineered bacterium for producing the N-acetyl-5-methoxytryptamine comprises a caffeic acid O-methyltransferase gene and a methionine adenosine transferase gene or/and a methionine synthetase gene, and can be used for producing a large amount of caffeic acid O-methyltransferase with biological activity and methionine adenosine transferase or/and methionine synthetase in cells. According to the method, through overexpression of the caffeic acid-O methyltransferase (COMT) gene and the methionine adenosine transferase gene or/and the methionine synthetase gene, an N-acetyl-5-methoxytryptamine biosynthesis pathway is reconstructed, and the synthesis yield of N-acetyl-5-methoxytryptamine is obviously increased.

The invention belongs to the technical field of biology, and relates to a high-selectivity probe of non-cobalt-dependent methionine synthase in higher plants and application thereof. The highly selective probe contains sulfonyl fluoride groups and is capable of specifically and covalently labeling proteins at lysine residues. The probe can be used for detecting the activity and expression quantityof non-cobalt-dependent methionine synthase in higher plants and positioning tissues and subcells. The probe provided by the invention provides a targeted protein research tool, so that deeper research on protein expression changes and protein network maps of different plant types, different strains or different development stages can be realized.

The invention discloses a method for preparing S-adenosylmethionine by an enzyme method capable of eliminating key impurities. The method comprises the following steps: step 1, constructing gene-deleted escherichia coli: knocking out a speD gene in escherichia coli BL21 (DE3) to obtain gene-deleted escherichia coli which does not generate S-adenosylmethionine decarboxylase; and 2, transforming the escherichia coli by using a recombinant plasmid containing a target gene: expressing the S-adenosylmethionine synthetase gene metK by using a gene deletion bacterium, culturing and inducing by using an inducer, and directly applying a crude enzyme liquid extracted after expression to enzyme reaction to produce S-adenosylmethionine. The method has the effect of greatly reducing the subsequent SAM purification cost.