5 results about "Heat inactivation" patented technology

The invention provides a property-changed fructose-1, 6-diphosphate aldolase mutant and application thereof, and relates to the technical field of enzyme engineering. According to the invention, a series of enzyme mutants with enhanced structural stability are obtained by carrying out rational design and site-directed mutagenesis on key sites of wild fructose-1, 6-diphosphate aldolase. Compared with a wild type, the mutant can keep certain enzyme activity at high temperature, shows excellent heat resistance, can be used as a core biocatalyst to efficiently catalyze a chiral compound synthesis reaction taking dihydroxyacetone phosphate as a key precursor, can still keep high catalytic efficiency at 50 DEG C, and can be used for preparing a chiral compound. The key bottleneck that natural enzyme is prone to thermal inactivation in industrial application is solved, and the method has wide application prospects in green biological manufacturing of high-added-value products such as drug intermediates and rare sugar.

The invention provides a high temperature resistant feruloyl esterase and an application thereof. The feruloyl esterase wild type has a remarkable high-temperature-resistant characteristic and still shows relatively high thermal stability under the condition of 95 DEG C, and the thermal inactivation half-life period of the feruloyl esterase wild type can reach 5h. On the basis, after the feruloyl esterase mutant obtained through structural rationality modification continuously reacts for 5 h at the temperature of 75 DEG C, floccule precipitation is not observed, and stable catalytic activity is kept. In the application, the feruloyl esterase mutant disclosed by the invention and commercial xylanase have a synergistic effect, so that the release of bound ferulic acid in starch-removed wheat bran can be effectively promoted. The invention provides a novel enzymology tool for efficiently and quickly releasing the plant-derived ferulic acid under a high-temperature condition.

The present application belongs to the technical field of biological detection, and provides a kit for detecting cytokines in blood samples. The kit comprises fluorescent coded polystyrene magnetic microspheres coupled with capture antibodies, biotin-labeled paired detection antibodies, streptavidin-labeled phycoerythrin with a final concentration of 0.5-2 ug / mL, a washing buffer containing 0.05%-0.1% Tween-20 or triton-100, an experimental buffer containing 0.5%-2% bovine serum albumin, and a sample diluent. The sample diluent comprises the experimental buffer and treated human serum. The treated human serum is obtained by first heat inactivation and carbon adsorption treatment of human serum, and then centrifugal separation using an ultrafiltration centrifugal tube. By using the kit provided by the present application, quantitative results of 7 cytokines can be obtained in a single detection of a single sample, and the detection range can reach 0.977-128000 pg / mL.

The invention provides a property-changed dihydroxyacetone kinase mutant and application thereof, and relates to the technical field of enzyme engineering. Through rational design and molecular modification, wild dihydroxyacetone kinase is subjected to single-point mutation and combined mutation, a series of enzyme mutants with enhanced thermal stability are obtained, and the catalytic activity of the mutants under the high-temperature condition is remarkably superior to that of wild enzymes. The invention further provides a multienzyme coupling reaction system containing the dihydroxyacetone kinase mutant, and the multienzyme coupling reaction system is used for efficiently catalyzing the process of synthesizing lactic acid by taking dihydroxyacetone as a substrate. The thermostable dihydroxyacetone kinase mutant provided by the invention solves the key bottleneck that a wild enzyme is easy to thermally inactivate under industrial application conditions, and has important industrial application prospects.

The application relates to a glutamine transaminase with improved thermal stability and application thereof, and belongs to the technical field of genetic engineering and protein engineering. The variant comprises a leading peptide and a mature polypeptide. The parent mature polypeptide of the variant corresponds to the region of the N terminal 4th to 13th of the wild-type SmTG mature polypeptide, and is replaced by a target sequence composed of n repeating units connected head to tail. The repeating unit has at least 80% identity with the original sequence, and is independently substituted by a specific amino acid at the corresponding 10th position, wherein at least two repeating units have different types of substitution amino acids at the 10th position. The remaining amino acid region of the parent mature polypeptide has at least 85% sequence identity with the remaining region of the wild-type SmTG mature polypeptide. Compared with the parent, the variant has a glutamine transaminase activity, and the thermal inactivation half-life at 60 DEG C is significantly prolonged by at least 0.3 times.