Abstract: Disclosed is a method for quantifying L-tryptophan involving a step for mixing a specimen, L-tryptophan oxidase, and water, a step for allowing the obtained reaction solution to stand a predetermined period of time in the presence of oxygen, and a step for measuring the reaction product resulting from action of enzymes present in the reaction solution after allowing to stand. The L-tryptophan oxidase has a given amino acid sequence and has oxidase activity that generates hydrogen peroxide and ammonia by acting on the L-tryptophan in the presence of oxygen and water. The oxidase activity of the L-tryptophan oxidase on the L-phenylalanine is in the range of 0-3% of the oxidase activity thereof on the L-tryptophan, and the L-tryptophan oxidase does not have oxidase activity on protein-constituting amino acids other than L-tryptophan and L-phenylalanine. Also disclosed are a kit used to quantify the L-tryptophan containing L-tryptophan oxidase, and an enzyme sensor using the L-tryptophan oxidase.

Abstract: An improved hydroxynitrile lyase characterized by having a mutation of substitution of at least one amino acid residue in the amino acid sequence of a wild-type hydroxynitrile lyase with another amino acid and by its hydroxynitrile lyase activity per transformant being higher than the hydroxynitrile lyase activity per transformant into which the wild-type hydroxynitrile lyase gene is introduced; and a method for producing a hydroxynitrile lyase, comprising expressing the improved hydroxynitrile lyase in a host and recovering the improved hydroxynitrile lyase from the resultant culture.

Abstract: A method for analyzing L-threonine contained in an specimen, which includes the steps of mixing a sample containing the specimen with an L-threonine dehydrogenase derived from Cupriavidus necator and a coenzyme NAD+ and analyzing the amount of NADH or 2-amino-3-oxobutyric acid after a predetermined period; an L-threonine dehydrogenase derived from Cupriavidus necator, which is a novel L-threonine dehydrogenase (TDH; EC 1.1.1.103) and can be utilized in the above-mentioned analysis method; a method for preparing a gene or the like to be used in the preparation of the enzyme, or a method for preparing the enzyme; an L-threonine analysis kit which includes (A) the L-threonine dehydrogenase and (B) a coenzyme NAD+; an enzyme preparation for use in the analysis of L-threonine, which includes the L-threonine dehydrogenase contained in a buffer solution; and an enzyme sensor utilizing the L-threonine dehydrogenase.

Abstract: An improved hydroxynitrile lyase characterized by having a mutation of substitution of at least one amino acid residue in the amino acid sequence of a wild-type hydroxynitrile lyase with another amino acid and by its hydroxynitrile lyase activity per transformant being higher than the hydroxynitrile lyase activity per transformant into which the wild-type hydroxynitrile lyase gene is introduced; and a method for producing a hydroxynitrile lyase, comprising expressing the improved hydroxynitrile lyase in a host and recovering the improved hydroxynitrile lyase from the resultant culture.

Abstract: Disclosed is a method for producing (S)-1,1,1-trifluoro-2-propanol with high optical purity and high yield by having at least one kind of microorganism, which is selected from the group consisting of Hansenula polymorpha, Pichia anomala, Candida parapsilosis, Candida mycoderma, Pichia naganishii, Candida saitoana, Cryptococcus curvatus, Saturnospora dispora, Saccharomyces bayanus and Pichia membranaefaciens, act on 1,1,1-trifluoroacetone. Since microorganisms found in nature are made to act in a natural state, the problems to be raised when a transformant or the like is used can be avoided in this method. Consequently, the method can be easily put in industrial practice.

Abstract: An improved hydroxynitrile lyase characterized by having a mutation of substitution of at least one amino acid residue in the amino acid sequence of a wild-type hydroxynitrile lyase with another amino acid and by its hydroxynitrile lyase activity per transformant being higher than the hydroxynitrile lyase activity per transformant into which the wild-type hydroxynitrile lyase gene is introduced; and a method for producing a hydroxynitrile lyase, comprising expressing the improved hydroxynitrile lyase in a host and recovering the improved hydroxynitrile lyase from the resultant culture.

Abstract: An improved hydroxynitrile lyase characterized by having a mutation of substitution of at least one amino acid residue in the amino acid sequence of a wild-type hydroxynitrile lyase with another amino acid and by its hydroxynitrile lyase activity per transformant being higher than the hydroxynitrile lyase activity per transformant into which the wild-type hydroxynitrile lyase gene is introduced; and a method for producing a hydroxynitrile lyase, comprising expressing the improved hydroxynitrile lyase in a host and recovering the improved hydroxynitrile lyase from the resultant culture.

Abstract: An improved hydroxynitrile lyase characterized by having a mutation of substitution of at least one amino acid residue in the amino acid sequence of a wild-type hydroxynitrile lyase with another amino acid and by its hydroxynitrile lyase activity per transformant being higher than the hydroxynitrile lyase activity per transformant into which the wild-type hydroxynitrile lyase gene is introduced; and a method for producing a hydroxynitrile lyase, comprising expressing the improved hydroxynitrile lyase in a host and recovering the improved hydroxynitrile lyase from the resultant culture.

Abstract: A recombinant microorganism is produced by introducing a DNA encoding an enzyme which hydrolyzes an amido bond of L-amino acid amide, especially L-2-alkylcysteine amide, and L-amino acid is produced by using cells or cell processed product of the obtained microorganism.

Abstract: An optically active amino acid is useful as food or feed, agrochemicals, chemical products for industrial use, intermediates for synthesis of cosmetics or medicines and the like and is also important as optical resolving agents or chiral building blocks for use in organic synthesis. Thus, the object is to provide an industrially practical method for producing the optically active amino acid simply and at low cost.

Abstract: A recombinant microorganism is produced by introducing a DNA encoding an enzyme which hydrolyzes an amido bond of L-amino acid amide, especially L-2-alkylcysteine amide, and L-amino acid is produced by using cells or cell processed product of the obtained microorganism.

Abstract: An improved hydroxynitrile lyase characterized by having a mutation of substitution of at least one amino acid residue in the amino acid sequence of a wild-type hydroxynitrile lyase with another amino acid and by its hydroxynitrile lyase activity per transformant being higher than the hydroxynitrile lyase activity per transformant into which the wild-type hydroxynitrile lyase gene is introduced; and a method for producing a hydroxynitrile lyase, comprising expressing the improved hydroxynitrile lyase in a host and recovering the improved hydroxynitrile lyase from the resultant culture.

Abstract: A recombinant microorganism is produced by introducing a DNA encoding an enzyme which hydrolyzes an amido bond of L-amino acid amide, especially L-2-alkylcysteine amide, and L-amino acid is produced by using cells or cell processed product of the obtained microorganism.

Abstract: A recombinant microorganism is produced by introducing a DNA encoding an enzyme which hydrolyzes an amido bond of L-amino acid amide, especially L-2-alkylcysteine amide, and L-amino acid is produced by using cells or cell processed product of the obtained microorganism.

Abstract: There is provided a mutant nucleoside-5?-phosphate producing enzyme with improved nucleoside-5?-phosphate producing ability of a nucleoside-5?-phosphate producing enzyme that has transphosphorylation activity and/or phosphatase activity and has one Lys residue, two Arg residues and two His residues with distances between their C?'s within a particular ranges and a space around them allowing a binding of a nucleoside, of which mutation is designed by using the crystal structure of EB-AP.

Abstract: A fuel assembly for a pressurized water reactor having control rod guide thimbles (5) each having a dashpot (12) for protecting against flexural deformation which may impair insatiability of a control rod. The fuel assembly includes, a plurality of control rod guide thimbles (5) having bottom and top end portions fixedly secured to a lower nozzle (2) and an upper nozzle (4), respectively, disposed in opposition to each other. The dashpot (12) of each control rod guide thimble (5) includes a small diameter section (13b) having an outer diameter smaller than that of the control rod guide thimble (5) formed at an upper portion of the dashpot (12), and a large diameter section (13a) having an outer diameter substantially equal to that of the control rod guide thimble (5) formed at a lower portion of the dashpot (12). With the length of the control rod guide thimble (5) represented by L, the effective length (S) of the small diameter section (13b) is selected to lie within a range of from 0.03 L to 0.1 L.

Abstract: A fuel assembly for a pressurized water reactor having control rod guide thimbles (5) each having a dashpot (12) for protecting against flexural deformation which may impair insatiability of a control rod. The fuel assembly includes, a plurality of control rod guide thimbles (5) having bottom and top end portions fixedly secured to a lower nozzle (2) and an upper nozzle (4), respectively, disposed in opposition to each other. The dashpot (12) of each control rod guide thimble (5) includes a small diameter section (13b) having an outer diameter smaller than that of the control rod guide thimble (5) formed at an upper portion of the dashpot (12), and a large diameter section (13a) having an outer diameter substantially equal to that of the control rod guide thimble (5) formed at a lower portion of the dashpot (12). With the length of the control rod guide thimble (5) represented by L, the effective length (S) of the small diameter section (13b) is selected to lie within a range of from 0.03 L to 0.1 L.

Abstract: A method for producing nucleoside-5′-phosphate esters inexpensively and in high yields by phosphorylating a nucleoside with a phosphate group donor using an acid phosphatase having an increased affinity for the nucleoside and/or an increased temperature stability at a pH of pH 3.0 to 5.5, to produce a nucleoside-5′-phosphate ester. Mutant acid phosphatases having increased affinity for nucleosides and/or an enhanced temperature stability are also provided.

Abstract: A method for producing nucleoside-5′-phosphate esters inexpensively and in high yields by phosphorylating a nucleoside with a phospahte group donor using an acid phosphatase having an increased affinity for the nucleoside and/or an increased temperature stability at a pH of pH 3.0 to 5.5, to produce a nucleoside-5′-phosphate ester. Mutant acid phosphatases having increased affinty for nucleosides and/or an enhanced temperature stability are also provided.

Abstract: The apparatus enables measurement of the amount of contaminant in a welded portion to high accuracy and in a short time, using an X-ray fluorescence inspection apparatus. The end portion of a fuel rod having a bead portion on an end surface of an end plug is covered with an approximately cylindrical cap, with the bead portion exposed via a central aperture. The material of the cap is preferably titanium. With titanium the fluorescent X-ray radiation has a different wavelength from that of tungsten and zircaloy, and the amount of fluorescent X-ray radiation detected by a detector at a diffraction angle of the spectrum W-L &agr; of fluorescent X-ray radiation for tungsten is less than those for tungsten and zircaloy. Therefore, while the fluorescent X-ray radiation of the cap which covers the end surface of the end plug around the bead portion results in noise, the amount of this fluorescent X-ray radiation measured by the detector is much smaller than for the tungsten and the zircaloy of the bead portion.