5 results about "Alanine dehydrogenase" patented technology

The application discloses an alanine dehydrogenase mutant, an L-alanine high-yield strain containing the same and application of the L-alanine high-yield strain. The amino acid sequence of the alanine dehydrogenase mutant of the application comprises one or more amino acid mutations of E48T, T180I, H295A, A304E and N344I compared with SEQ ID NO:1. The L-alanine high-yield strain expresses the above alanine dehydrogenase mutant, can produce high-concentration L-alanine through fermentation culture, has the ability of short fermentation time, reaches 136.5 g / kg in 38 hours of fermentation, has a sugar-acid conversion rate as high as 97%, has improved fermentation level and greatly shortened fermentation time, and has the potential of industrial application.

The application discloses an alanine dehydrogenase mutant, wherein 1-3 amino acids in positions 165, 177, 178, 180, 199, 200, 217, 218, 219, 225, 237 and 238 of the wild-type alanine dehydrogenase amino acid sequence shown in SEQ ID NO. 1 are respectively mutated into one of lysine, arginine, glutamic acid, proline, valine, glycine, alanine and serine. The alanine dehydrogenase mutant has significant preference for NAD(H) analogues, can produce L-alanine or pyruvic acid by using NAD analogues and NADH analogues, and does not cause interference problems. The application further discloses application of the alanine dehydrogenase mutant.

The invention discloses a double-enzyme sensing system for detecting ochratoxin A and application of the double-enzyme sensing system. The invention provides a method for detecting OTA in a to-be-detected sample, which comprises the following steps: A1) carrying out hydrolysis reaction on the to-be-detected sample by using amide hydrolase to obtain a first-step reaction solution; a2) adding phenylalanine dehydrogenase, coenzyme NAD < + > and Glycine into the first-step reaction solution, and reacting again to obtain a second-step reaction solution; adding a color developing agent into the second-step reaction solution, and carrying out color developing reaction to obtain a reaction product; detecting OTA in the sample to be detected according to the reaction product; according to the invention, a novel OTA degrading enzyme ThADH of an OTA sensing element and a product L-phenylalanine sensing element phenylalanine dehydrogenase are combined, and efficient, visual and quantitative detection of OTA is realized by using a color reaction in a product catalysis process.

The invention discloses a colorimetric biosensing system based on phenylalanine dehydrogenation, which is used for detecting ochratoxin A. The invention provides a method for detecting OTA in a to-be-detected sample, which comprises the following steps: A1) carrying out hydrolysis reaction on the to-be-detected sample by using amide hydrolase VeADH to obtain a first-step reaction solution; a2) adding phenylalanine dehydrogenase, coenzyme NAD < + > and Glycine into the first-step reaction solution, and reacting again to obtain a second-step reaction solution; adding a color developing agent into the second-step reaction solution, and carrying out color developing reaction to obtain a reaction product; detecting OTA in the sample to be detected according to the reaction product; according to the invention, a novel OTA degrading enzyme VeADH of an OTA sensing element and a product L-phenylalanine sensing element phenylalanine dehydrogenase are combined, and efficient, visual and quantitative detection of OTA is realized by using a color reaction in a product catalysis process.

The invention relates to an AlaDH mutant and an application of the AlaDH mutant in production of L-serine. Specifically, the invention provides an alanine dehydrogenase AlaDH mutant, and the alanine dehydrogenase AlaDH mutant has amino acid substitutions of L107A, K161V and E205D or a combination of any two of the amino acid substitutions of L107A, K161V and E205D relative to wild alanine dehydrogenase AlaDH. The present invention also provides a method of producing L-serine or an L-serine derivative, the method comprising culturing a bacterium in a culture medium wherein the bacterium comprises a nucleotide sequence encoding the AlaDH mutant. According to the AlaDH mutant disclosed by the invention, 3-PHP can be specifically catalyzed to generate 3Per, so that the generation of byproducts is reduced, and the production cost is reduced.