9results about How to "Inhibit enzyme activity" patented technology

The application discloses a whitening and freckle-removing composition containing white tomato and chases yellow grass, a preparation method and application thereof, and belongs to the technical field of food, wherein the whitening and freckle-removing composition is composed of white tomato powder and chases yellow grass powder with a weight ratio of 1-3:2-7. The preparation method comprises the following steps: (1) beating, separating, concentrating and drying white tomatoes to obtain white tomato powder; (2) soaking chases yellow grass in acidic water, performing solid-liquid separation, concentrating and drying the obtained clear liquid to obtain chases yellow grass powder; and (3) mixing the white tomato powder and the chases yellow grass powder. The application utilizes the combination of white tomatoes and chases yellow grass, and improves the preparation process of chases yellow grass, so that the two components produce a synergistic effect in inhibiting tyrosinase activity and inhibiting melanin production.

The application belongs to the technical field of biological medicine, and particularly relates to a polypeptide degradation agent for targeted degradation of CD26 and a preparation method and application thereof. The polypeptide degradation agent is obtained after coupling of a tetrapeptide and lenalidomide. The amino acid sequence of the tetrapeptide is any one of SEQ ID NO. 1 and SEQ ID NO. 2. The polypeptide degradation agent can specifically target and degrade DPP4, i.e. CD26, but cannot degrade DPP4 isozymes such as DPP7, DPP8 and DPP9, and thus has high selectivity. In addition, the polypeptide degradation agent has small molecular weight, one end is a natural short peptide, has good tissue compatibility, can quickly degrade target proteins in 6 hours, and thus has good tissue permeability.

The present invention relates to a specific binding protein targeting PD-L1 and CD73, wherein the specific binding protein is capable of specifically binding to PD-L1 and / or a fragment thereof, and CD73 and / or a fragment thereof. The present invention further relates to use of the specific binding protein in the treatment, prevention and / or diagnosis of diseases such as immune diseases, acute and chronic inflammatory diseases, and tumor diseases.

The application discloses a quinazoline-4(3H)-ketone compound and a preparation method, a pharmaceutical composition and application thereof, the structure of the compound is as shown in the formula (I), and the compound comprises isomers, pharmaceutically acceptable salts or mixtures thereof. The compound and the pharmaceutical composition thereof have a high inhibitory effect on PARP7, the inhibitory activity reaches a nanomolar concentration level, can significantly promote the release of immune factors, are used for immunotherapy of tumors, and can exert good drug efficacy at a molecular level and a cell level. In addition, the preparation method of the compound is simple and easy to implement.

The invention belongs to the technical field of tobacco detection, and particularly discloses a tobacco volatile matter detection method based on headspace solid-phase microextraction and salting-out combination. Comprising the following steps: S1, removing main veins from sample tobacco leaves, drying, preparing into powder, sealing, and storing in a refrigerator for later use; s2, the tobacco leaf powder is placed in a headspace bottle, an internal standard compound is added, then a boiling salt solution is added, microextraction fibers aged in advance are inserted, water bath extraction and adsorption are carried out, and after extraction is completed, the microextraction fibers are inserted into a GC-MS injection port for desorption; and S3, performing qualitative and quantitative treatment on the volatile substances by adopting GC-MS. The method adopts an HS-SPME method for extraction, does not introduce organic solvent interference, and is simple and rapid to operate, low in cost, high in detection sensitivity and high in detection efficiency.

Provided are a nucleic acid ligand (nucleic acid polymerase substrate analog), a mixture thereof, and the use thereof. The mixture of the nucleic acid polymerase substrate analog contains two or more nucleic acid polymerase substrate analogs. The nucleic acid polymerase substrate analog is a single nucleic acid molecule or nucleic acid molecule analog which forms complementary pairing within a molecule, or a single or two nucleic acid molecules or nucleic acid molecule analogs which form complementary pairing between molecules; and a structure formed thereby has the characteristics of a nucleic acid polymerase substrate. When an amplification reaction mixture is at or below a certain temperature, the enzyme activity of a nucleic acid polymerase is inhibited by means of the nucleic acid ligand and there is no residual enzyme activity. When the reaction mixture is heated, the nucleic acid polymerase is separated from the nucleic acid polymerase substrate analog to exert activity and form a primer extension product, thereby achieving the effect of inhibiting non-specific amplification. The nucleic acid polymerase substrate analog is suitable for all polymerases and can be widely used in the field of nucleic acid amplification. The 3' end of the nucleic acid ligand has a modification which inhibits the extension thereof.

The application discloses a use of hydrogen peroxide (H2O2) in constructing an oxidative stress model of female and male chicken primordial germ cells (PGCs); in the application, the H2O2 can achieve the effect of oxidative stress of the female and male chicken PGCs by increasing the ROS content in the female and male chicken PGCs, inhibiting the T-SOD and CAT enzyme activities and increasing the MDA content; the application verifies the effect of the oxidative stress model established by the H2O2 on the female and male chicken PGCs by screening different concentrations of the H2O2 added into the female and male chicken PGCs and then detecting the apoptosis, reproductive markers, mitochondrial functions and autophagy genes of the cells; in the application, the effect of the oxidative stress model constructed by the H2O2 on the female and male chicken PGCs provides new experimental basis for clarifying the molecular mechanism of oxidative stress causing poultry reproductive damage, and provides new ideas and targets for protecting the PGC functions of poultry and improving the reproductive efficiency by regulating the oxidative stress, autophagy or apoptosis pathways in the future, and provides important research and development basis for the selection of compounds resisting oxidative stress.

The present invention relates to a composite method for controlling the discoloration of frozen fruits in acidic juice, and belongs to the technical field of fruit freezing processing. The main steps of the present invention include: 1) raw material selection; 2) pretreatment; 3) negative pressure ultrasonic penetration and pre-dehydration; 4) acid-resistant hydrogel impregnation; 5) non-thermal enzyme treatment; 6) electromagnetic coupling assisted impregnation quick freezing and acid-resistant hydrogel freezing coating; 7) acid protective film plating; 8) packaging. The frozen fruits processed by this process can be directly used in acidic juice (pH < 3.5) to keep the color unchanged for a long time, meeting the actual production needs; the developed composite color preservative can avoid the shortcomings of the use of single color preservatives and dyes, and has the characteristics of safety, greenness and high efficiency.

This invention belongs to the field of biomedical technology and relates to a polypeptide targeting cGAS and its applications. The polypeptide comprises an active peptide and a membrane-penetrating peptide, the membrane-penetrating peptide being fused to the N-terminus of the active peptide. The amino acid sequence of the active peptide is identical to amino acid regions 45-63 of human IκB kinase-binding protein (IKIP) or 43-60 of mouse IKIP. The polypeptide provided by this invention can enter cells, specifically bind to cGAS, inhibit cGAS aggregation and phase separation, thereby inhibiting cGAS enzyme activity, reducing type I interferon expression, maintaining antiviral immune homeostasis, and providing a new candidate strategy for the clinical treatment of viral infections and autoimmune diseases.