63 results about "Dihydrofolic acid" patented technology

The invention discloses a GS-DHFRmut double-gene screening expression vector, and a preparation method and an application thereof, and belongs to the biotech field. The expression vector contains a promoter controlling the expression of a glutamine synthetase gene, the glutamine synthetase gene, a promoter controlling the expression of a mutant dihydrofolate reductase gene, and the mutant dihydrofolate reductase gene, and the downstream of each of two screening genes has a PolyA signal sequence. The invention also discloses the preparation method of the expression vector and the application of the expression vector. The GS-DHFRmut double-gene screening expression vector improves the expression level of an exogenous protein, enlarges the use resource of host cell strains in the genetic engineering, and has an important application value in the industrialized development of the genetic engineering.

Compounds of the formula I: wherein R1, R2, R1' and R2' are independently hydrogen or a group releasing the free amine in vivo, R6 is a substituted phenyl or an optionally substituted, bicyclic or tricyclic aryl ring system or an optionally substituted mono, bi- or tricyclic heteroaryl ring system having utility as DHFR inhibitors with favourable pharmacokinetic properties.

The invention provides a combined medicine having efficacy of antineoplastic drugs. The combined medicine consists of chlorogenic acid and a dihydrofolate reductase inhibitor of unit preparations in same or different specifications, and a pharmaceutically acceptable carrier, wherein the chlorogenic acid and the dihydrofolate reductase inhibitor are applied in a simultaneous or separated mode. According to the combined medicine, a synergistic effect can be developed when the chlorogenic acid and the DHFR (dihydrofolate reductase) inhibitor are used in a combined mode, and hematopoietic function injury and weight loss caused by the DHFR inhibitor can be relieved; toxic and side effects of the DHFR inhibitor can be effectively reduced; and the medicine, which combines the chlorogenic acid and the DHFR inhibitor is excellent in curative effect, low in toxicity and good in prospect of clinical application.

Cells and cell lines are disclosed that are able to produce therapeutic proteins, antibodies, vectors, and viral vectors such as lentiviral vectors and adeno-associated viral (AAV) vectors. The cells and/or cell lines can have mutations or deletions in either one or both of the endogenous di-hydrofolate reductase (DHFR−/−) or glutamine synthetase (GS−/−) genes such that DHFR and/or GS expression or function is substantially reduced or eliminated.

The invention relates to a reagent (kit) for measuring formaldehyde by using an enzyme-multiplied method, an enzyme colorimetric method and an enzyme coupling method as well as a method for measuring the concentration of the formaldehyde, and composition and ingredients of the reagent, belonging to the technical field of food/environmental test. The reagent (kit) comprises the main ingredients of buffer solution, coenzyme, adenosine triphosphoric acid, tetrahydrofolic acid, glyceric aldehyde-3-phosphoric acid, formaldehyde dehydrogenase, formic acid-dihydrofolic acid ligase, glyceric aldehyde-3-glycerol phosphate dehydrogenase and stabilizing agent. The concentration of the formaldehyde is measured by mixing a sample and the reagent according to a certain volume ratio to carry out a series of enzymatic reaction, placing the reactant under an ultraviolet/visible light analyzer and detecting the ascending degree of absorbance at a dominant wavelength of 340nm.

The invention belongs to the technical field of enzymatic synthesis, and relates to a method for preparing L-5-calcium methyl tetrahydrofolate through an enzymic method. The method comprises the following steps that 1, folic acid serves as the raw material, and zinc powder is used for making zinc powder reduced to be dihydrofolic acid; 2, dihydrofolic acid reductase and glucose dehydrogenase are added in dihydrofolic acid, and a reaction is conducted to obtain L-tetrahydrofolic acid; 3, formaldehyde and hydroboron are added in L-tetrahydrofolic acid, and a reaction is conducted for obtaining L-5-methyltetrahydrofolate; 4, L-5-methyltetrahydrofolate is salified, and L-5-calcium methyl tetrahydrofolate is obtained. Accordingly, the effective method for preparing L-5-calcium methyl tetrahydrofolate through the enzymic method is provided, the preparation method is free of splitting, mild in reaction, high in yield, high in product purity and friendly to environment, and has a very good industrial prospect.

The invention relates to a homocysteine diagnosis/determination reagent (kit) using enzyme-colorimetry and enzyme-linked method technology. Meanwhile, the invention also relates to a homocysteine concentration determination method, reagent composition and component, which belongs to the technical filed of medical test and determination. The reagent (box) of the invention mainly includes: buffer solution, coenzyme, 5-methyltetrahydrofolate, methionine synzyme, dihydrofolate reductase and stabilizing agent; samples and reagent are mixed according to a certain volume ratio to generate a series of enzymatic reactions; then the reactants are arranged under an ultraviolet/visible light analyzer to detect the increasing degree of absorbance at the 340nm position of a dominant wave so as to measure and calculate the concentration of the homocysteine.

A method for identifying a protein as being able to bind a ligand comprising, providing a molecule composed of a methotrexate moiety that is covalently bonded to the ligand; introducing the molecule into a cell which a) expresses a first fusion protein comprising a dihydrofolate reductase capable of binding methotrexate, expresses b) a second fusion protein comprising the protein, wherein one of the first and second fusion proteins also comprises a transcription activator domain and the other comprises a DNA-binding domain, and c) has a reporter gene wherein expression of the reporter gene is conditioned on the proximity of the first fusion protein to the second fusion protein; permitting the molecule to bind to the first fusion protein and to the second fusion protein so as to activate the expression of the reporter gene; and selecting the cell if it expresses the reporter gene.

The invention provides a DHFR-based multi-residue fluorescence polarization immunoassay method for sulfonamide synergist drugs, which is characterized in that dihydrofolate reductase DHFR is derived from sulfanilamide synergist drug sensitive strains, including staphylococcus aureus, streptococcus pneumoniae and mycobacterium tuberculosis. According to the invention, a sulfanilamide synergist drug multi-residue fluorescence polarization immunoassay method based on the sulfanilamide synergist drug receptor protein dihydrofolate reductase is established for the first time, the established method is applied to multi-residue detection of sulfanilamide synergist drugs in milk, and a method technical support is provided for screening of sulfanilamide synergist drugs in food. According to the invention, DHFR from sulfanilamide synergist drug sensitive strains is creatively adopted, and the method is initiated in the field. The method breaks through the limitation of the conventional method, expands the application range, and has the advantages of rapidness, simplicity, accuracy and the like.

The invention provides a coupling compound which is a compound as shown in a formula (I) or a stereoisomer, a tautomer, a homologue, a solvate, a metabolite, a pharmaceutically acceptable salt or a prodrug of the compound as shown in the formula (I), A is a linking group, and B is a dihydrofolate reductase inhibitor.

Belonging to the field of chemical pharmacy, the invention relates to a preparation method of a standard drug impurity substance, in particular to the preparation method of a calcium levofolinate impurity and an impurity calcium salt. Firstly, the invention provides a preparation method of calcium levofolinate impurity, and the method includes: taking the compound folic acid shown as formula I asthe raw material for reaction with a reductant in an aqueous solution, and adjusting the pH value of the reaction solution with an alkali aqueous solution and inorganic acid respectively to obtain thecompound dihydrofolic acid shown as formula II; and reacting the compound shown as II with formic acid, adding purified water, and performing stirring and filtering to obtain the compound 10-formyl dihydrofolate shown as formula III. The invention also provides a preparation method of 10-calcium formyl dihydrofolate, and the method includes: taking folic acid as the raw material, firstly preparing dihydrofolic acid, then reacting dihydrofolic acid with formic acid to obtain 10-formyl dihydrofolate, then adding a calcium salt, and carrying out reaction to obtain 10-calcium formyl dihydrofolate.