Abstract: When a terminal sequence to be investigated is specified (S1), a corresponding protein is extracted from a database containing known proteins linked with terminal sequences (S2). If one protein cannot be uniquely identified (“No” in S5), amino-acid residues to be bonded to the target terminal sequences are selected, and new terminal sequences with the selected amino-acid residues respectively added are created for further investigation (S7). Each new terminal sequence is examined as to whether or not one protein can be uniquely identified from it, and if not so, another amino-acid residue is added. While such processes are repeated, if it has been found that the protein can be uniquely identified before the sequence length reaches an upper limit, the sequence length is displayed (S9). If the sequence length has reached the upper limit without successful identification, a message saying that the protein cannot be identified is displayed (S11).

Abstract: The present invention provides a mass spectrometry method capable of detecting a smaller amount of peptide. A method for analyzing a peptide by matrix-assisted laser desorption/ionization mass spectrometry, comprising the steps of: dropping, onto a target plate, a peptide solution using, as a solvent, an aqueous solution containing 15 to 50 vol % of acetonitrile, and a matrix solution that uses, as a solvent, an aqueous solution containing 15 to 50 vol % of acetonitrile and that contains 0.05 to 1 mg/mL ?-cyano-4-hydroxycinnamic acid, respectively, to prepare a droplet of peptide-matrix mixed solution; removing the solvent from the droplet of peptide-matrix mixed solution to prepare a sample for mass spectrometry as a residue; and irradiating the sample for mass spectrometry with laser to detect the peptide.

Abstract: According to the present invention, a matrix reagent prepared by adding methylenediphosphonic acid (MDPNA) having two phosphonic acid groups as an additive to a matrix of 2,5-dihydroxybenzoic acid (DHBA) is used for the preparation of a sample. By using the sample according to the present invention, it is possible to achieve a higher peak intensity of phosphopeptide as compared with a sample in which DHBA is solely used as a matrix without using an additive, or a sample in which phosphoric acid (PA) is used as an additive in addition to DHBA. Further, use of the sample according to the present invention enables the detection of peptides that cannot be detected in a case of the phosphoric acid-added sample.

Abstract: The present invention provides a method for inexpensively, easily and efficiently modifying the C-terminus of a protein or peptide; a method for easily and reliably isolating a C-terminal peptide fragment of a protein or peptide; and a method for rapidly, accurately and reliably determining an amino acid sequence of a protein or peptide by using a mass spectroscope. A method comprising the step of adding a formylation reagent and a catalyst to a protein or peptide to convert a carboxyl group into an aldehyde group. A method comprising the step of reacting a nucleophilic reagent with the aldehyde group to modify the C-terminus of the protein or peptide. A method comprising the step of reacting a support having a nucleophilic group to immobilize the protein or peptide. A method comprising the step of fragmenting the immobilized protein or peptide, washing the support, and isolating the C-terminal peptide fragment from the support.

Abstract: The present invention provides a method for effectively introducing sulfonic acid groups into the N-terminus of a protein or a peptide. The method comprises a modification step to react a N-terminus in a protein or peptide with a compound A which includes disulfide group and a cleavage step to cleave a disulfide bond of the disulfide group to convert into a sulfonic acid group. The present invention also provides a method of analyzing proteins or peptides easily and effectively on mass spectrometry and an intermediate that can be used to effectively derivatize proteins or peptides as sulfonic acid derivatives.

Abstract: The present invention provides a method for specifically recovering a C-terminal peptide fragment, and a method for easily determining the sequence of a C-terminal peptide fragment, which is difficult to be determined by a conventional method, with the use of a mass spectrometer, in particular a method capable of de novo sequencing of a C-terminal peptide fragment. A method for selectively recovering a C-terminal peptide of a protein, comprising the steps of: in a cleavage product of a protein containing a C-terminal peptide fragment (A) having an ?-amino group but not having an ?-amino group and the other peptide fragments (B) having an ?-amino group and an ?-amino group, selectively modifying the ?-amino groups to obtain a C-terminal peptide fragment modified (A?) and the other peptide fragments modified (B?); and separating the C-terminal peptide fragment modified (A?) from the modified cleavage product by allowing a carrier to hold the other peptide fragments modified (B?) via the ?-amino group.

Abstract: According to the present invention, a matrix reagent prepared by adding methylenediphosphonic acid (MDPNA) having two phosphonic acid groups as an additive to a matrix of 2,5-dihydroxybenzoic acid (DHBA) is used for the preparation of a sample. By using the sample according to the present invention, it is possible to achieve a higher peak intensity of phosphopeptide as compared with a sample in which DHBA is solely used as a matrix without using an additive, or a sample in which phosphoric acid (PA) is used as an additive in addition to DHBA. Further, use of the sample according to the present invention enables the detection of peptides that cannot be detected in a case of the phosphoric acid-added sample.

Abstract: A simple and low-cost method of selectively modifying the C-terminal of a protein or peptide is provided. A method of modifying the C-terminal of a protein or peptide comprises forming an intramolecular oxazolone ring at the C-terminal of the protein or peptide that requires C-terminal modification, and then performing a ring-opening of the oxazolone ring to produce a protein or peptide with a modified C-terminal.

Abstract: A method for eliminating a phosphate group of a peptide, the method comprising the use of a reagent containing at least one selected from the group consisting of hydrogen fluoride, hydrofluoric acid, and a hydrogen fluoride-containing compound, and a method for peptide analysis that uses such a method. As the hydrogen fluoride-containing compound, hydrogen fluoride-pyridine is preferably used. The elimination of the phosphate group from a peptide may be carried out so that the total amount of the hydrogen fluoride, hydrogen fluoride in the hydrofluoric acid, and hydrogen fluoride in the hydrogen fluoride-containing compound contain in the reagent is 10 to 100 wt % with respect to the reagent, and the temperature for the elimination reaction is ?10 to 50° C.

Abstract: The present invention provides a method capable of efficiently ionizing hydrophobic peptides in MALDI-IT, MALDI-IT-TOF, and MALDI-FTICR mass spectrometers. A method of measuring a peptide with a mass spectrometer having a MALDI (Matrix Assisted Laser Desorption/Ionization) ion source, using ?-cyano-3-hydroxycinnamic acid or 3-hydroxy-4-nitrobenzoic acid as a matrix. Preferably, a peptide derivatized with 2-nitrobenzenesulfenyl chloride is measured with a MALDI-IT, MALDI-IT-TOF, or MALDI-FTICR mass spectrometer. When 3-hydroxy-4-nitrobenzoic acid is used as a matrix, the matrix is preferably used as a mixed matrix in which ?-cyano-4-hydroxycinnamic acid is combined.

Abstract: A sulfenyl compound represented by the general formula: R—S—X (I)(wherein R represents an organic group having at least one constituent element labeled with an isotope, and X represents a leaving group); a labeling reagent comprising it; and a method of analyzing peptide using the labeling reagent. Preferably the organic group R comprises C, H, and N, and optionally O and/or P as the constituent element, and the isotope is a stable isotope selected from the group consisting of 2H, 13C, 15N, 17O, and 18O.

Abstract: A simple and low-cost method of selectively modifying the C-terminal of a protein or peptide is provided. A method of modifying the C-terminal of a protein or peptide comprises forming an intramolecular oxazolone ring at the C-terminal of the protein or peptide that requires C-terminal modification, and then performing a ring-opening of the oxazolone ring to produce a protein or peptide with a modified C-terminal.

Abstract: The present invention provides a method for effectively introducing sulfonic acid groups into the N-terminus of a protein or a peptide; a method capable of analyzing proteins or peptides easily and effectively on mass spectrometry; an intermediate that can be used to effectively derivatize proteins or peptides as sulfonic acid derivatives. A method for derivatizing a protein or peptide to a sulfonic acid derivative, comprising steps of: modification step to react a N-terminus in a protein or peptide with a compound A which includes disulfide group, to obtain a protein or peptide modified with the compound A at the N-terminus; and cleavage step to cleave a disulfide bond of the disulfide group to convert into a sulfonic acid group, thereby converting the modified protein or peptide into a sulfonic acid derivative. A method for analyzing the amino acid sequence of a protein or peptide, wherein the sulfonic acid derivative of a protein or a peptide obtained by the above method is subjected to mass spectrometry.

Abstract: The present invention provides a novel metal complex useful for a reagent for determining the amino acid sequence of protein or peptide, and a method of using it for determining the amino acid sequence of protein or peptide. The metal complex which has a functional group capable of forming a covalent bond with the amino group of the N-terminal amino acid residue of protein or peptide or with the carboxyl group of the C-terminal amino acid residue of protein or peptide. In general, the functional group is in the ligand of the complex.

Abstract: A crosslinked polycarbonate is obtained by polycondensation of diol (A), trivalent or more polyhydric alcohol (B) whose arbitrary two hydroxy groups are not in the positional relationship of 1,2-disubstitution or 1,3-disubstitution, and carbonyl component (C) such as carbonic acid diesters. In the polycondensation step, no side reaction does not occur.This crosslinked polycarbonate is used as a modifier for polylactic acids. The brittleness of the polylactic acid is improved while maintaining mechanical strength, thermostability, and transparency.

Abstract: The polylactic acid-based resin composition includes (a) (i) 100 parts by weight of a poly-L-lactic acid; or (ii) 100 parts by weight of a poly-DL-lactic acid comprising L-lactic acid and D-lactic acid as its constituting units; and (b) 5 to 120 parts by weight of at least one of low-molecular lactic acid derivatives. The molded product is produced by the steps of 1) melt-kneading (a) one of the above components (i) or (ii) and the component (b); and 2) subjecting the melt-kneaded product obtained in step 1) to an injection molding, to give a desired molded product.

Abstract: Thermal detectors comprising at least one pair of membrane electrodes formed on a base material (such a pyroelectric, semiconductive and insulating materials), wherein at least one member of said pair of electrodes is covered with a black membrane of precious metal formed by the electrolytic process, are highly sensitive because of the excellent heat absorption efficiency, with little change in sensitivity over a wide wavelength range.