34 results about "Lactic acid dehydrogenase activity" patented technology

A high flux of metabolites from pyruvate to 2,3-butanediol in Lactobacillus plantarum was achieved through genetic engineering. Substantial elimination of lactate dehydrogenase activity in the presence of heterologously expressed butanediol dehydrogenase activity led to 2,3 butanediol production that was at least 49% of the total of major pyruvate-derived products.

A high flux of metabolites from pyruvate to 2,3-butanediol in Lactobacillus plantarum was achieved through genetic engineering. Substantial elimination of lactate dehydrogenase activity in the presence of heterologously expressed butanediol dehydrogenase activity led to 2,3 butanediol production that was at least 49% of the total of major pyruvate-derived products.

The invention discloses a method for stabilizing activity of alpha-hydroxybutyricdehydrogenase and lactic dehydrogenase of quality-control serum, comprising the step of freezing and drying a mixture composed of other proteins, trehalose, mannite, glycine, quality-control serum and buffer solution. By the method in the invention, a freeze-drying quality-control serum containing alpha-HBDH and LDH and with stable properties and low price can be provided, the freeze-drying alpha-HBDH and LDH quality-control serum is stable and can be stored in a long term, the activity of the two enzymes of alpha-HBDH and LDH has no obvious change after hydrated reconstruction.

There is disclosed a yeast strain of Candida utilis, wherein the yeast strain has been transformed with at least one copy of a gene that is operatively linked to a promoter sequence enabling expression of the gene and encodes a polypeptide having activity of lactate dehydrogenase. The yeast strain is useful for producing lactic acid with high efficiency.

Succinic acid is produced by allowing a bacterium modified to enhance fumarate reductase activity or cell preparation thereof to react with an organic raw material in a reaction solution containing one of a carbonate ion, a bicarbonate ion, and carbon dioxide gas to generate succinic acid. More preferably, succinic acid is produced by allowing a bacterium modified to enhance activities of fumarate reductase and pyruvate carboxylase and decrease lactate dehydrogenase activity or cell preparation thereof to react with an organic raw material in a reaction solution containing one of a carbonate ion, a bicarbonate ion, and carbon dioxide gas to generate succinic acid. Succinic acid is obtained by collecting the produced succinic acid.

A thermophilic microorganism lacks lactate dehydrogenase activity and preferably contains an active pyruvate formate lyase pathway. The thermophilic microorganism contains a gene encoding an NAD-linked formate dehydrogenase. The gene encoding an NAD-linked formate dehydrogenase is preferably a codon optimised version of the gene encoding a thermostable NAD-linked formate dehydrogenase. DNA constructs allow stable expression of the gene encoding an NAD-linked formate dehydrogenase in the thermophilic microorganism. The DNA constructs are based upon use of an insertion sequence to achieve stable expression or recombination to insert the gene encoding an NAD-linked formate dehydrogenase into the lactate dehydrogenase gene, thus achieving gene knockout and new functionality in a single step. The microorganisms are useful in fermentation of sugars to produce ethanol.

It is intended to provide a fungus of the genus Rhizopus having improved ability to produce lactic acid and a method for producing lactic acid using the fungus. The present invention provides a method for improving the lactate dehydrogenase activity of a fungus of the genus Rhizopus, comprising germinating a spore of a fungus of the genus Rhizopus in a culture medium containing a surfactant under specific conditions to obtain a mycelium, and a method for producing lactic acid using the mycelium of the fungus of the genus Rhizopus.

The invention discloses an application of dioscin in preparation of a liver-protecting pharmaceutical preparation. The pharmaceutical preparation can obviously inhibit increase of activity of aminotransferase and lactate dehydrogenase due to medicines (carbon tetrachloride or paracetamol) and alcohol, and reduce the liver indices, thereby performing the liver-protecting function; the pharmaceutical preparation can enhance the activity of SOD, reduce the content of MDA, increase the content of GSH and inhibit liver lipide overoxidation induced by medicines (carbon tetrachloride or paracetamol); and the pharmaceutical preparation can also reduce the content of TG and TC and inhibit the liver steatosis caused by alcohol. The dioscin can be used as the raw material to prepare various preparation formulations for clinic applications according to pharmaceutic related requirements and clinic requirements, such as tablets, capsules, injections, oral liquids, granules and the like. The invention is safe (no toxicity or side effect), convenient, economical and the like.

The invention discloses a functional yoghurt product with the inhibitory activity of alpha-glucosidase and tyrosinase, and a preparation method thereof. The functional yoghurt product is characterizedby performing superfine crushing on fleeceflower root and kudzuvine root, then performing mixing with water, skim milk powder and sugar in a certain proportion, and performing a process of stirring and uniform mixing, filtering, colloid mill emulsification, sterilization, cooling, Lactobacillus plantarum, Lactobacillus acidophilus and Streptococcus thermophilus starter addition, uniform mixing, filling, fermentation, cooling and post-ripening to obtain the yoghurt product with the inhibitory activity of alpha-glucosidase and tyrosinase and the anti-fatigue function. The advantages are that the content of polyphenols and flavonoid aglycones can be significantly increased, the activity of serum glutathione peroxidase, superoxide dismutase and lactate dehydrogenase in mice is increased, andthe content of malondialdehyde and urea nitrogen is reduced.

The invention discloses a D-lactic dehydrogenase mutant and application thereof. Protein is protein shown in the sequence A or is protein which has the same function, is derived from the sequence A and is formed by substituting, and / or deleting and / or adding one or more amino acid residues to the protein shown in the sequence A; the sequence A is a sequence obtained by mutating Met at the <307>th bit into Leu in the sequence 2. It is proved through experiments that D-LDH 744 form Sporolactobacillus inulinus is selected and mutated to obtain the D-lactic dehydrogenase mutant M307L. The mutant has high D-lactic dehydrogenase activity, and compared with D-lactic dehydrogenase without mutation, and enzyme activity of D-LDH with PPA (phenylpropanolamine hydrochloride) as a substrate is improved.

The present invention provides a transformant into which has been incorporated DNA for coding a foreign protein having lactate dehydrogenase activity and provided with pyruvic acid substrate affinity that equals or exceeds the pyruvic acid substrate affinity of the pyruvate decarboxylase inherent in the host organism. Said transformant can stably mass-produce lactic acid inside a host organism having the pyruvate decarboxylase gene.

The present disclosure pertains to a genetically modified microorganism that satisfies some of specific requirements. The specific requirements include: (I) compared to a wild type microorganism, having reduced or inactivated succinate dehydrogenase activity or fumarate reductase activity; (II) compared to a wild type microorganism, having reduced or inactivated lactate dehydrogenase activity; (III) having a modified phosphoenolpyruvate carboxylase activity and thus showing resistance against the feedback inhibition by aspartic acid in wild type phosphoenolpyruvate carboxylase activity, or having an exogenous phosphoenolpyruvate carboxylase activity and thus showing higher resistance against the feedback inhibition by aspartic acid than wild type phosphoenolpyruvate carboxylase activity shown by a wild type microorganism; and (IV) compared to a wild type microorganism, having reduced or inactivated pyruvate : quinone oxidoreductase.

The invention discloses a measuring method for lactic dehydrogenase activity based on a titanium dioxide film field-effect tube. The measuring method comprises the following steps: (1) preparing a titanium dioxide film through a sol-gel method: cleaning a silicon plate, preparing a solution, rotatably coating and annealing; (2) connecting a coating electrode to three electrodes; (3) performing enzyme immobilization; (4) detecting enzyme activity: using KEITHLEY 4200 to test electrical properties of the field-effect tube for enzyme activity detection, testing an I-V curve of lactic dehydrogenase of D-S under different grid voltages, and performing instant detection after dropwise adding lactic acids of different concentrations, detecting on multiple reaction time points, and observing I-V curve changes of D-S at different reaction times. The measuring method does not need test paper, is short in test period, is quick in response, and can be used for realizing quick detection for enzymeactivity. Needed enzyme is low in concentration, is small in size, and can be immobilized enzyme. The measuring method is simple, and provides a novel method for measuring enzyme activity in blood serum.

Described herein are host cells comprising lactate dehydrogenase activity, lactaldehyde dehydrogenase activity, lactaldehyde reductase activity, propanediol dehydratase activity, and / or n-propanol dehydrogenase activity, wherein the cells are capable of producing n-propanol. Also described are methods of producing n-propanol comprising (a) cultivating the host cells having lactate dehydrogenase activity, lactaldehyde dehydrogenase activity, lactaldehyde reductase activity, propanediol dehydratase activity, and / or n-propanol dehydrogenase activity in a medium under suitable conditions to produce n-propanol; and (b) recovering the n-propanol. Methods of producing polypropylene from the recombinant n-propanol are also provided.

The invention discloses a preparation method and an application of a protein nutritional food with an anti-fatigue efficacy, belongs to the field of functional foods and particularly relates to a food with a significant efficacy on sports fatigue relieving. The protein nutritional food prepared by adopting the method disclosed by the invention comprises the following main nutritional base materials in parts by weight: 44-46 parts of soy protein isolate and 53-55 parts of whey protein according to the detection of the nitrogen content of each protein. By adopting the protein nutritional food with equal nitrogen ratio, through seven-week nutrition intervention in a rat after loaded swimming in still water, the lactic dehydrogenase activity in the rat can be remarkably increased and the loaded swimming exhaustive time of the rat is prolonged on the premise of not increasing the weight of the rats. The food has an obvious efficacy on sports fatigue relieving and the average loaded swimming exhaustive time of the rat is up to 135 seconds, so that the food has a good utilization value in anti-fatigue functional food development.

The invention discloses a quality classification method for frozen shelled shrimps, which performs quality classification according to the activity of lactate dehydrogenase of the frozen shelled shrimps and the sensory score of the frozen shelled shrimps, and comprises the following steps: 1) sampling; 2) extracting and measuring of the fribrillin; 3) measuring the activity value of the lactate dehydrogenase; and 4) classifying the quality according to the activity of lactate dehydrogenase of the frozen shelled shrimps and the sensory score of the frozen shelled shrimps. According to the method, the frozen shelled shrimps at least can be divided into three quality grades, namely poor grade (failing to be determined), middle grade (determined, but small value), and good grade (determined, big value).

Rice protein concentrates prepared at low temperature exhibit improved functionality and beneficial physiological benefits, including lowered cholesterol and enhanced lactic acid dehydrogenase activity, without an increase in blood urea nitrogen. The rice protein concentration could be made into a wet dough with comparatively less water than a soy protein concentrate. Use of the rice protein concentrate thus improved processing steps in the formulation of a food article containing the concentrate. The food product advantageously shows an extending shelf life and improved palatable texture.

The invention discloses a method for regulating the lactic acid secretion level of immature sertoli cells of pigs and application. The invention discloses a method for adjusting the lactic acid secretion level of a porcine immature sertoli cell line by changing the HSP90AA1 gene level, and belongs to the field of cell gene engineering. Specifically, the HSP90AA1 gene expression level is changed by transfecting an HSP90AA1 overexpression vector and a specific inhibitor to treat the immature testicular cells, and the lactic acid synthesis level of the immature testicular cells indicated by the HSP90AA1 level is judged by a method for determining the lactic acid generation and lactic dehydrogenase activity through enzyme-linked reaction. The result shows that the HSP90AA1 can positively regulate and control the lactic acid synthesis of the immature sertoli cells of the pigs, and can be used as a method for regulating the lactic acid secretion level of the immature sertoli cells of the pigs.

The invention discloses a preparation method and application of sleeve-fish collagen polypeptide and an iron complex thereof. A high-temperature acetic acid hydrolysis method is utilized to prepare the sleeve-fish collagen polypeptide and the iron complex thereof from sleeve-fish skin which is a byproduct of sleeve-fish processing, and the preparation method is stable in reaction condition, easy to control and free of pollutant emission and meets requirements on clean production. Animal experiments show that the sleeve-fish collagen polypeptide and the iron complex thereof can remarkably increase hypoxia tolerance survival time, improve activity of in-vivo lactic dehydrogenase and reduce content of in-vivo blood lactic acid and blood urea nitrogen. Results show that hypoxia tolerance activity can be remarkably improved by adopting either the sleeve-fish collagen polypeptide or the iron complex, and the sleeve-fish collagen polypeptide and the iron complex can be used for preparing hypoxia-tolerant drug and functional food and are of important significance in developing and utilizing marine medicinal biological resources in China.

The present invention relates to a method for preparing a D-lactic acid-producing strain modified to inhibit L-lactate dehydrogenase (L-LDH) activity and to introduce D-lactate dehydrogenase (D-LDH) activity in an L-lactic acid-producing strain, a mutated D-lactic acid-producing strain prepared by the above method, and a method for producing D-lactic acid including the steps of culturing the strain and recovering D-lactic acid from the culture media.

The present invention provides a method for producing lactic acid in a recombinant yeast cell culture using glucose as carbon source comprising a first, seed fermentation stage to produce biomass wherein the yeast is cultivated in a culture medium at a pH of 5 to 7, followed by a second, a production fermentation stage with biomass from the seed fermentation to produce lactic acid, wherein the yeast is cultivated in a culture medium at low p H using a yeast strain that is engineered to have lactate dehydrogenase (LDH) activity and optionally has decreased or knocked-out pyruvate decarboxylase (PDC) activity.

The invention discloses a preparation method and an application of a protein nutritional food with an anti-fatigue efficacy, belongs to the field of functional foods and particularly relates to a food with a significant efficacy on sports fatigue relieving. The protein nutritional food prepared by adopting the method disclosed by the invention comprises the following main nutritional base materials in parts by weight: 44-46 parts of soy protein isolate and 53-55 parts of whey protein according to the detection of the nitrogen content of each protein. By adopting the protein nutritional food with equal nitrogen ratio, through seven-week nutrition intervention in a rat after loaded swimming in still water, the lactic dehydrogenase activity in the rat can be remarkably increased and the loaded swimming exhaustive time of the rat is prolonged on the premise of not increasing the weight of the rats. The food has an obvious efficacy on sports fatigue relieving and the average loaded swimming exhaustive time of the rat is up to 135 seconds, so that the food has a good utilization value in anti-fatigue functional food development.

The invention discloses a measuring method for lactic dehydrogenase activity based on a titanium dioxide film field-effect tube. The measuring method comprises the following steps: (1) preparing a titanium dioxide film through a sol-gel method: cleaning a silicon plate, preparing a solution, rotatably coating and annealing; (2) connecting a coating electrode to three electrodes; (3) performing enzyme immobilization; (4) detecting enzyme activity: using KEITHLEY 4200 to test electrical properties of the field-effect tube for enzyme activity detection, testing an I-V curve of lactic dehydrogenase of D-S under different grid voltages, and performing instant detection after dropwise adding lactic acids of different concentrations, detecting on multiple reaction time points, and observing I-V curve changes of D-S at different reaction times. The measuring method does not need test paper, is short in test period, is quick in response, and can be used for realizing quick detection for enzymeactivity. Needed enzyme is low in concentration, is small in size, and can be immobilized enzyme. The measuring method is simple, and provides a novel method for measuring enzyme activity in blood serum.

The invention discloses an application of dioscin in preparation of a liver-protecting pharmaceutical preparation. The pharmaceutical preparation can obviously inhibit increase of activity of aminotransferase and lactate dehydrogenase due to medicines (carbon tetrachloride or paracetamol) and alcohol, and reduce the liver indices, thereby performing the liver-protecting function; the pharmaceutical preparation can enhance the activity of SOD, reduce the content of MDA, increase the content of GSH and inhibit liver lipide overoxidation induced by medicines (carbon tetrachloride or paracetamol); and the pharmaceutical preparation can also reduce the content of TG and TC and inhibit the liver steatosis caused by alcohol. The dioscin can be used as the raw material to prepare various preparation formulations for clinic applications according to pharmaceutic related requirements and clinic requirements, such as tablets, capsules, injections, oral liquids, granules and the like. The invention is safe (no toxicity or side effect), convenient, economical and the like.