7 results about "Cyanogen bromide" patented technology

The invention discloses a preparation method of methoxy imidazo [1, 5-a] pyridine, which comprises the following steps: firstly, taking a compound P1, specifically 1-methylamino-3-methoxypyridine, as an initial raw material, and carrying out carbamylation reaction in a formylation reagent to prepare a compound P2, specifically N-[(5-methoxypyridine-2-yl) methyl]; further carrying out intramolecular ring closing reaction on the compound P2 to obtain a compound P3 which is specifically 7-methoxy imidazo [1, 5-a] pyridine; then, a selective bromination experiment at the C3 position is carried out by taking a compound P3 as a parent skeleton and cyanogen bromide (CNBr) as a bromination reagent, and finally, specific bromination of the C3 site of the imidazo [1, 5-a] pyridine with the selectivity of 100% is realized. A solid theoretical basis is laid for efficient specific modification of the low-reaction-activity C3 site, and an efficient synthesis path is provided for rapid construction of the imidazopyridine derivative, so that the imidazopyridine derivative has a wide application prospect.

The application discloses a nucleic acid aptamer capable of specifically recognizing a cyanogen bromide-activated substrate material and application thereof. The nucleic acid aptamer can specifically bind to the cyanogen bromide-activated substrate material and comprises a nucleotide sequence selected from any one of SEQ ID NO: 1-4 in the sequence listing or a nucleotide sequence derived from the nucleotide sequence through substitution, deletion, insertion of one or more nucleotides and / or chemical modification. The application develops a novel nucleic acid probe immobilization method by utilizing the interaction between the nucleic acid aptamer and the cyanogen bromide-activated substrate material and applies the method in the fields of biosensing, affinity enrichment and separation and reagent kit development. In addition, by constructing a fusion allosteric nucleic acid aptamer, the interaction between the two can be used as a signal output strategy to realize detection of target objects such as nucleic acids, proteins, small molecules, cells and exosomes.

The present application belongs to the technical field of culture additive of bacteria, and particularly relates to a preparation method of N-acyl-homoserine lactone. The present application can obtain homoserine and homoserine lactone by lysing methionine through cyanogen bromide after extracting protein from soybean, although other proteins exist in the lysing mixture, but do not have influence on the subsequent ring formation (dehydration). The homoserine lactone salt obtained after ring formation is substituted by alkyl chlorides with different carbon chain lengths, and different AHLs signal molecules can be obtained.

The invention discloses a preparation method and application of a fatty acid transporter FATP transmembrane domain. The method comprises the following steps: fusing a gene for coding an FATP transmembrane domain with a TrpLE tag sequence, and performing high-efficiency expression in escherichia coli to form an inclusion body. Thirdly, primarily purifying the fusion protein by using nickel column affinity chromatography, and specifically releasing a target transmembrane peptide fragment through cyanogen bromide chemical cleavage; and finally, carrying out fine purification by adopting one-step reversed-phase high-performance liquid chromatography to obtain a milligram-grade high-purity peptide fragment. The purified peptide fragment can be successfully reconstructed in a plurality of membrane simulation systems such as Fos-choline-14 micelles or DMPC / DHPC (Dimethyl Polycarbonate / Dimethyl Hexaphthyl Polycarbonate) lipid saucers and the like. According to the method, high-level expression of the FATP transmembrane domain in escherichia coli is achieved, the purification process is simple, convenient and efficient, the final product is high in purity, the yield can reach the milligram level, and the method is suitable for stable isotope labeling and meets the requirements of fine structure research such as nuclear magnetic resonance.

The application discloses high-purity chicken plasma fibronectin and a preparation method thereof. The method comprises the following steps: taking fresh chicken plasma as raw material, adding ammonium sulfate to a saturation degree of 20% at low temperature to realize targeted extraction and enrichment of fibronectin; then, a gelatin affinity chromatography column is prepared through gelatin-cyanogen bromide (CNBr) activation gel coupling, specific binding of fibronectin and gelatin is utilized to realize efficient capture and preliminary purification, and gradient arginine solution is adopted to realize impurity washing and elution; finally, high-purity and high-activity fibronectin is obtained through desalination of dextran gel G25 chromatography. Through optimization of the combination process of ammonium sulfate precipitation, specific affinity chromatography and gel filtration, the problems of low purity, easy damage of activity, low efficiency and high cost in the traditional method are solved, the purpose of high-value preparation of high-purity fibronectin from by-product chicken blood is realized. The purity can reach 92.93%, and the high-purity chicken plasma fibronectin can be applied to the fields of biomedicine, cosmetics and cell culture.

The invention belongs to the technical field of synthesis of perfluoronitrile compounds, and particularly relates to a method for continuously synthesizing perfluoroisobutyronitrile, which comprises the following steps of: mixing gasified 2-bromoheptafluoropropane and cyanogen bromide, preheating, reheating, carrying out cyanation reaction, cooling to obtain cooling liquid and mixed gas, and compressing, condensing, rectifying and drying the mixed gas to obtain the perfluoroisobutyronitrile. The perfluoroisobutyronitrile preparation method disclosed by the invention can realize continuous production, and has the advantages of simple process, low production cost, mild reaction conditions and no need of a catalyst and a solvent.

The subject of this invention is a construct of an expression vector for expressing recombinant µ-conotoxin TIIIA or TIIIAlaMut, characterized in that it comprises the nucleotide sequence of µ-conotoxin TIIIA SEQ ID NO:1 or the nucleotide sequence of µ-conotoxin TIIIAlaMut SEQ ID NO:4, both sequences containing a sequence encoding six histidine residues (6His) at the 5' end, which is linked via a serine-glycine-serine linker (SGS) to a construct encoding a TRX::TIIIA fusion protein or a TRX::TIIIAlaMut fusion protein, wherein the TRX::TIIIA fusion protein comprises the µ-conotoxin TIIIA gene and a gene encoding a leader protein, and the TRX::TIIIAlaMut fusion protein comprises the µ-conotoxin TIIIAlaMut gene and a leader protein, wherein the leader protein is a thioredoxin (TRX) modified by site-directed mutagenesis, wherein the amino acid methionine at position 37 is replaced by lysine. Another subject of the invention is an expression vector comprising a construct according to the invention under the control of a constitutive promoter. Another subject of the invention is isolated *E. coli* cells comprising an expression vector according to the invention. Another subject of the invention is a method for producing µ-conotoxin TIIIA or TIIIAlaMut in *E. coli* using an expression vector comprising a construct according to the invention, characterized in that the method comprises the steps of: a) transforming *E. coli* cells with an expression vector comprising a construct according to the invention under the control of a constitutive promoter, said expression vector encoding a TRX::TIIIA fusion protein having the amino acid sequence SEQ ID NO:2 or having SEQ ID NO:2. a) TRX::TIIIAlaMut fusion protein NO:5; b) Expression of the TRX::TIIIA or TRX::TIIIAlaMut fusion protein; c) Isolation and purification of the TRX::TIIIA or TRX::TIIIAlaMut fusion protein; d) Formation of disulfide bonds by glutathione treatment of the purified TRX::TIIIA or TRX::TIIIAlaMut fusion protein in GSH / GSSG and dialyzing in buffer; e) Cleavage of the TRX::TIIIA or TRX::TIIIAlaMut fusion protein with the formed disulfide bonds by cyanogen bromide; f) Purification of the cleaved TIIIA or TIIIAlaMut peptide.