Disclosed is a mutant of acid phosphatase and an application thereof, belonging to the technical field of biological engineering. The disclosure provides a mutant of acid phosphatase PaAPase.sub.Mu3. By expressing the mutant of acid phosphatase PaAPase.sub.Mu3 in Escherichia coli and using a whole-cell conversion method, L-ascorbic acid is transformed into L-ascorbate-2-phosphate. Moreover, a catalytic system of the mutant of acid phosphatase PaAPase.sub.Mu3 is optimized from the aspects of reaction pH and temperature, so that a yield of L-ascorbate-2-phosphate can reach 90.1 g/L and a molar yield can reach 75.1%. Therefore, the problems of a high substrate cost, environmental pollution and the like before are greatly reduced, laying a foundation for the industrial green production of L-ascorbate-2-phosphate.

The present invention provides a recombinant microorganism for producing citicoline and a method for producing citicoline by using the recombinant microorganism, wherein genes for degradation and utilization of citicoline, choline, and phosphocholine are knocked out, In addition, a pyrimidine nucleoside synthesis pathway is genetically engineered to remove feedback inhibition to the synthesis pathway. A yield of more than 20 g/L of citicoline can be obtained with recombinant strains in a 5-liter fermenter by means of a biological fermentation method, achieving industrial mass production with low citicoline production costs and less pollution; therefore, the method is a simple, environmentally friendly and has a relatively high promotion and application value.

The invention relates to a genetically modified prokaryotic cell capable of improved iron-sulfur cluster delivery, characterized by a modified gene encoding a mutant Iron Sulfur Cluster Regulator (IscR) and one or more transgenes or upregulated endogenous genes encoding iron-sulfur (Fe—S) cluster polypeptides or proteins that catalyze complex radical-mediated molecular rearrangements, electron transfer, radical or non-redox reactions, sulfur donation or perform regulatory functions. The prokaryotic cells are characterized by enhanced activity of these iron-sulfur (Fe—S) cluster polypeptides, enhancing their respective functional capacity, and facilitating enhanced yields of compounds in free and protein-bound forms, including heme, hemoproteins, tetrapyrroles, B vitamins, amino acids, δ-aminolevulinic acid, biofuels, isoprenoids, pyrroloquinoline quinone, ammonia, indigo, or their precursors, whose biosynthesis depends on their activity. The invention further relates to a method for producing said compounds or their precursors using the genetically modified prokaryotic cell of the invention, and the use of the genetically modified prokaryotic cell.

Biomarkers to screen for, identify, and/or characterize lung cancer in a subject with high selectivity and high specificity are disclosed. Also disclosed herein are methods for distinguishing lung cancer from another disease. Also disclosed herein are substrates, arrays, and reagents for use in the methods, and methods of their preparation.

Provided are phytase mutants, preparation methods therefor and uses thereof, DNA molecule encoding each of the phytase mutants, a vector comprising the DNA molecule, and a host cell comprising the vector.

The invention provides non-naturally occurring microbial organisms containing a fatty alcohol, fatty aldehyde or fatty acid pathway, wherein the microbial organisms selectively produce a fatty alcohol, fatty aldehyde or fatty acid of a specified length. Also provided are non-naturally occurring microbial organisms having a fatty alcohol, fatty aldehyde or fatty acid pathway, wherein the microbial organisms further include an acetyl-CoA pathway. In some aspects, the microbial organisms of the invention have select gene disruptions or enzyme attenuations that increase production of fatty alcohols, fatty aldehydes or fatty acids. The invention additionally provides methods of using the above microbial organisms to produce a fatty alcohol, a fatty aldehyde or a fatty acid.

Described is a method for the production of fructose-6-phosphate (F6P) from dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (G3P) comprising the steps of: (a) enzymatically converting dihydroxyacetone phosphate (DHAP) into dihydroxyacetone (DHA); and (b) enzymatically converting the thus produced dihydroxyacetone (DHA) and glyceraldehyde-3-phosphate (G3P) into fructose-6-phosphate (F6P); or
comprising the steps of: (a′) enzymatically converting glyceraldehyde-3-phosphate (G3P) into glyceraldehyde; and (b′) enzymatically converting the thus produced glyceraldehyde together with dihydroxyacetone phosphate (DHAP) into fructose-1-phosphate (F1P); and (c′) enzymatically converting the thus produced fructose-1-phosphate (F1P) into fructose-6-phosphate (F6P).

The problem of detecting whether a urine sample is true human urine or a counterfeit urine product is solved by the use of reagent systems that detect two markers normally present in human urine. The markers acid phosphatase and alkaline phosphatase catalyze the substrates thymolphthalein monophosphate and p-nitrophenol phosphate, respectively. These substrates are formulated as spot tests on a dip stick or as reagents for use in automated chemical analyzers. The presence of the markers can be qualitatively detected by color-changes in the sample, formed by the pH-specific chromogens that result from catalysis of the substrates with the markers. The control reagent can further indicate whether a counterfeit urine product contains one or both of the chromogens.

Described is a method for the production of fructose-6-phosphate (F6P) from dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (G3P) comprising the steps of: (a) enzymatically converting dihydroxyacetone phosphate (DHAP) into dihydroxyacetone (DHA); and (b) enzymatically converting the thus produced dihydroxyacetone (DHA) and glyceraldehyde-3-phosphate (G3P) into fructose-6-phosphate (F6P); or
comprising the steps of: (a′) enzymatically converting glyceraldehyde-3-phosphate (G3P) into glyceraldehyde; and (b′) enzymatically converting the thus produced glyceraldehyde together with dihydroxyacetone phosphate (DHAP) into fructose-1-phosphate (F1P); and (c′) enzymatically converting the thus produced fructose-1-phosphate (F1P) into fructose-6-phosphate (F6P).

An acid phosphatase mutant, and method for preparing nicotinamide riboside by same. The mutant is a protein of the following (a), (b) or (c): (a) a protein, having an amino acid sequence shown in SEQ ID NO: 3; (b) a protein, derived from (a), having catalytic activity higher than an acid phosphatase parent having an amino acid sequence shown in SEQ ID NO: 2, obtained by substituting, deleting or adding several amino acids in the amino acid sequence shown in SEQ ID NO: 3, using nicotinamide mononucleotide as a substrate; (c) a protein, having catalytic activity higher than the acid phosphatase shown in SEQ ID NO: 2, having 90% or more homology with the amino acid sequence of the protein defined by (a) or (b), and using nicotinamide mononucleotide as a substrate. It is used to prepare nicotinamide riboside and the conversion rate can be 99%.