9 results about "Synthetase activity" patented technology

This invention relates to the fields of bioengineering and fermentation engineering, and discloses a genetically engineered *Streptomyces albopictus* strain that produces high levels of ε-polylysine and its fermentation production process. This genetically engineered strain uses *Streptomyces albopictus* strains acclimated to ε-polylysine tolerance as a chassis, and its genome integrates... ppc and dapf Through expression box, heterogeneous asd Expression cassettes, containing secretory signal peptides lysp Fusion expression cassettes and D404A / K499A point mutations pls Expression cassette. The fermentation process employs a two-stage pH control strategy, maintaining a neutral environment during the cell growth phase and adjusting to an acidic environment during product synthesis. This invention improves ε-polylysine yield through a synergistic strategy of enhancing precursor supply, constructing efflux detoxification channels, and increasing synthase activity; combined with an acidic fermentation process, it effectively inhibits product degradation, yielding a high-molecular-weight and highly uniform target product suitable for industrial production.

This invention discloses a culture medium for enhancing the activity of in vitro fiber-degrading bacteria in the gut microbiota, its preparation method, and its application, belonging to the field of microbial culture medium technology. The culture medium provided by this invention can effectively enhance the activity of fiber-degrading bacteria in the gut microbiota, promote their growth and metabolism, and thus significantly improve the fiber degradation capacity of in vitro microbiota. Compared with commonly used culture media, the concentration of total short-chain fatty acids in fiber fermentation products can be increased by up to approximately 50%. Compared with commonly used culture media, the culture medium provided by this invention can alter the composition of the fiber-degrading bacterial community in the gut microbiota, with significant differences detected in the abundance of nine genera, which may be the reason for the different fermentation efficiencies. The culture medium provided by this invention helps to more fully evaluate the fermentability of dietary fiber, and further study its metabolic pathways, product synthesis, enzyme activity, and biocatalytic mechanisms, which has significant value for the optimization of biomimetic digestive systems in the field of animal nutrition.

This invention discloses the application of lipoic acid analog formulations in the preparation of anti-cardiomyocyte senescence products. The lipoic acid analog DMAE-LA is N-(2-(dimethylamino)ethyl)-5-(1,2-dithiopentane-3-yl)pentanamide, with a concentration of 2-25 μM. DMAE-LA pretreatment effectively reduces intracellular ROS, improves mitochondrial function, inhibits the overexpression of p21 and HMGB1, and restores Lamin B1 levels, thereby alleviating the senescent manifestations of cardiomyocytes. DMAE-LA reduces H₂S oxidative depletion by inhibiting ROS generation and may promote H₂S synthase activity, increasing endogenous H₂S levels and further enhancing cellular antioxidant capacity. In summary, DMAE-LA can significantly inhibit cardiomyocyte senescence through multiple antioxidant mechanisms and organelle function protection, providing a potential intervention strategy for targeting cellular senescence in cardiovascular diseases.

The invention relates to a yeast gene modified cell containing GDP-fucose synthase polypeptide, which can be applied to synthesis of human milk oligosaccharide, and belongs to the technical field of gene engineering. According to the technical scheme, the yeast gene modified cell contains a heterologous nucleic acid sequence of a GDP-fucose synthase active polypeptide. The synthetase active polypeptide is obtained by modifying at least one site of the 20th site to the 29th site, the 40th site to the 53th site, the 75th site to the 81st site, the 95th site, the 148th site to the 158th site, the 193th site, the 215th site, the 219th site to the 21st site, the 227th site to the 232 site, the 239th site to the 241st site, the 259th site to the 264th site, the 301st site to the 302 site, the 306th site and the 310th site to the 316th site of an amino acid sequence shown in SEQ ID NO: 1. Compared with an original strain, the yeast gene modified cell has higher activity of synthesizing fucosyllactose, and a safe and feasible technical scheme is provided for industrial production of fucosyllactose.

The invention discloses a method for reducing the content of an M impurity in fusidic acid fermentation liquor. The generation of the M impurity is inhibited from a fermentation source by optimizing a fermentation culture medium and regulating and controlling pH in stages. A fermentation culture medium adopts a composite organic nitrogen source, contains soybean cake powder with specific grease content, and is matched with a yeast extract and corn steep liquor, so that a key precursor can be provided for fusidic acid synthesis, and the enzyme activity can be regulated; the pH is regulated in the early stage of fermentation to adapt to the proliferation requirement of the strain, M impurity synthesis is preliminarily inhibited, the pH is regulated in the middle and later stages to strengthen the activity of a target product synthetase, and M impurity synthetase expression is remarkably inhibited. The process is simple, subsequent complex purification is not needed, the yield of fusidic acid is increased, M impurities are reduced to 2% or below, and the method is suitable for industrial large-scale production.

The present application relates to the technical field of biological enzyme engineering, and particularly relates to a nicotinamide adenine dinucleotide synthetase mutant and application thereof. The nicotinamide adenine dinucleotide synthetase mutant is obtained by mutating W11F, M12R, H37W, I40V, I40L, G43A, G43D, L46D, L46E, V55D, V55E, F60W, Y61S, L112I, L112K, L125E, L133T and other sites of NadR as a parent, so that the mutant can efficiently catalyze low-cost substrates NR and ATP to generate NAD. In particular, by using the above-mentioned multi-mutation point mutation, the mutant has better substrate binding capacity and catalytic efficiency, higher NAD conversion rate and enzyme activity (up to 12.49 U / mg), not only solves the technical problem of low activity of the existing NAD synthetase, but also significantly reduces the production cost of NAD by using the low-priced NR to replace the expensive NMN as the substrate, and provides a more economically beneficial technical scheme for the industrial production of NAD.

The application discloses a genetic element for enhancing lactic acid metabolic flux of actinomycetes, and belongs to the field of synthetic biology and microbial metabolic engineering. sucC The application successfully constructs a single expression element and a co-expression element by cloning genes from Streptomyces coelicolor sucD , and verifies that the SucC protein and the SucD protein both have lactic acid coenzyme A synthetase activity through in-vitro protein purification and enzyme activity determination, and the enzyme activity of a protein complex (SucC-SucD, SucCD) expressed by the co-expression element is significantly higher than that of the single protein, indicating that the two proteins have a synergistic effect; the genetic element can efficiently catalyze the combination reaction of lactic acid and coenzyme A in vitro, accelerates the lactic acid metabolic speed, provides a core genetic element for the modification of the lactic acid metabolic pathway of actinomycetes, enriches a synthetic biology tool library, and has important industrial application prospects and academic value.

The invention discloses a mutant of acylase and application thereof. The invention discloses a swine acylase mutant as well as a coding gene and a genetically engineered bacterium thereof. The acylase mutant disclosed by the invention has high enzyme activity stability in a wider pH environment, meanwhile, the activity of octanoyl alanine synthetase is improved, the synthesis efficiency of an octanoyl surfactant is high, and the acylase mutant has very high production and application values.

This invention discloses the Modhephene synthase gene of Artemisia annua spirochetane-type sesquiterpenoids. AaTPS25 Its mutants and applications; the Modhephene synthase gene was first identified and cloned from Artemisia annua. AaTPS25 The study clarified that the encoded protein can catalyze the synthesis of Modhephene from FPP, laying the foundation for the study of the biosynthesis and cyclization mechanism of this compound. Through site-directed mutagenesis, the AaTPS25 mutant with enhanced activity and the AaTPS26-A295E / Q and AabrSPS-A295E / Q mutants with Modhephene synthase activity were obtained, enriching the Modhephene synthase gene resources and providing key evidence for improving the biosynthetic yield of Modhephene and studying its catalytic mechanism.