Abstract: The present invention relates to a method for quantitative determination of NAD(P)H derived from a specific component, which comprises converting NAD(P)H present in a sample or formed from components other than the objective component by reactions into NAD(P) by the action of glutathione of oxidation type and glutathione reductase; decomposing the remaining glutathione of oxidation type by the action of .gamma.-glutamyl transpeptidase in the presence or in the absence of a mercapto compound; forming NAD(P)H from the component to be determined in the sample utilizing an NAD(P)H-forming reaction system; and quantitatively determining NAD(P)H.According to the method of the present invention, amylase activity, etc. in vital components containing maltose and glucose can be determined accurately.

Abstract: A composition for testing periodontal diseases which diagnoses or prognosticates contraction or progress of the diseases or diagnoses the therapeutic value by promptly determining peptidase-like enzymatic activity in a specimen. The composition is a combination of a compound of the formula [1] or [2] or a mixture thereof, a chromogen and an oxidase:X-T-Pro-Y [1]orX'-Z'-Arg-Y' [2]wherein Pro is proline residue; Arg is arginine residue; X and X' are hydrogen or an amino protecting group, respectively; Y and Y' are a residue of a compound which can increase oxidation reaction rate of a chromogen with a oxidase in the presence of oxygen and is attached to the C-terminal of Pro or Arg, respectively; and T and Z' are an amino acid or peptide residue composed of 0 to 4 amino acids or their protected derivatives the C-terminal of which is attached to the N-terminal of Pro or Arg, respectively.

Abstract: Disclosed is a method for determination of an activity of .gamma.-glutamyl transpeptidase, leucine aminopeptidase, alanine aminopeptidase, cystine aminopeptidase, X factor as a coagulation factor, thrombin, plasmin of plasminogen series, kallikrein, chymotrypsin, alkali phosphatase, N-acetyl glucosaminase and amylase, by allowing a particular substrate to act on the enzyme to thereby form an enhancer; oxidizing a chromogen by an oxidase in the presence of the enhancer and oxygen to form a pigment; and determining the pigment. Also disclosed is a test composition for carrying out the determination.

Abstract: The present invention provides a method for the determination of a compound having mercapto group which comprises reacting the compound with a chromogen represented by the following general formula (I): ##STR1## wherein Y is hydrogen or hydroxyl; R.sub.1, R.sub.2 and R.sub.3 may be the same or different, and are groups represented by the following general formula (II), (III) or (IV): ##STR2## wherein Z (which may be the same or different) is hydroxyl, amino, substituted amino, alkyl, substituted alkyl, alkenyl, aryl, substituted aryl, acyl, halogen, nitro, sulfo, carboxyl or alkoxy; n is 0, 1, 2, or 3; provided that at least one Z in R.sub.1, R.sub.2 and R.sub.3 is hydroxyl, amino, or substituted amino, in the presence of peroxidase or thiol oxide reductase, and determining the pigment thus formed.

Abstract: Disclosed is a method for the colorimetric determination of hydrogen peroxide in a sample by reacting a particular chromogen with the hydrogen perioxide in the presence of peroxidase and measuring the absorbancy of the reaction solution in the visible or near inflared ray region. Also disclosed is a test composition for carrying out the determination.

Abstract: Leucine aminopeptidase (LAP) activity or .gamma.-glutamyltranspeptidase (.gamma.-GTP) activity in a sample is determined by converting a substrate represented by the formula (I): ##STR1## wherein Z represents (CH.sub.3).sub.2 CHCH.sub.2 CH(NH.sub.2)--or (NH.sub.2)(COOH) CHCH.sub.2 CH.sub.2 --, R.sub.1 represents hydrogen, alkyl or substituted alkyl, R.sub.2 represents alkylene or hydroxyalkylene, R.sub.3 and R.sub.4 are the same or different and represents hydrogen, halogen, nitro, hydroxyl, sulfo, carboxyl, alkyl, and alkoxy, and salts thereof into a compound represented by the formula (II): ##STR2## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 have the same meanings as defined above. The compound (II) is reacted with a chromogen to form a pigment or converted into a diazonium salt which is reacted with a coupling agent to form an azo dye. Absorption of a resultant colored reaction solution is measured.

Abstract: A method for the determination of peroxide in a sample is disclosed which comprises reacting the peroxide with a chromogen represented by the general formula (I) or (II) ##STR1## wherein R.sub.1 and R.sub.3 represent amino, mono- or di- substituted amino, hydroxyl or hydroxyalkyl, R.sub.4 and R.sub.5 represent hydrogen, alkyl, alkylene, acyl, halogen, sulphone, nitro, carboxyl, hydroxyl or hydroxyalkyl, R.sub.2 represents hydrogen, ##STR2## wherein R.sub.6 represents hydrogen, alkyl, aralkyl, alkylene, aryl or mono- or di- substituted aryl, and --Z-- may change to --Z.dbd. by resonance and represents --S--, --O--, --N.dbd., ##STR3## wherein R.sub.7, R.sub.8, R.sub.9 and R.sub.10 have the same significance as R.sub.6 in the presence of heme compound, iodide or bromide and measuring the absorbancy of the reaction solution in the visible ray region.

Abstract: The present invention provides a method for the determination of NAD(P)H which comprises reacting a chromogen represented by the following general formula (I): ##STR1## wherein Y is hydrogen or hydroxyl; R.sub.1, R.sub.2 and R.sub.3 may be the same or different, and are groups represented by the following general formula (II), (III) or (IV): ##STR2## wherein Z is hydrogen, hydroxyl, amino, substituted amino, alkyl, substituted alkyl, alkenyl, aryl, substituted aryl, acyl, halogen, nitro, sulfo, carboxyl or alkoxy; n is 1, 2, or 3; provided that at least one Z in R.sub.1, R.sub.2 and R.sub.3 is hydroxyl, amino, or substituted amino; and Z.sub.s in Z.sub.n may be the same or different, with NAD(P)H in the presence of (1) peroxidase or thiol oxide reductase and (2) diaphorase or an electron carrier, and determining the pigment thus formed.

Abstract: A method and test composition for colorimetrically determining hydrogen peroxide in a sample includes a chromogen of the formula: ##STR1## which is reacted with hydrogen peroxide in the sample in the presence of peroxidase. The absorbancy of the reaction solution is then measured.

Abstract: The present invention provides a method for the determination of bilirubin which comprises reacting the bilirubin with a compound represented by the formula ##STR1## and determing the pigment thus formed.

Abstract: A method for decomposing hydrogen peroxide is disclosed. The hydrogen peroxide is reacted with a compound represented by the formula (I) ##STR1## wherein Z represents OH or NR.sub.4.R.sub.5 wherein R.sub.4 and R.sub.5 are the same or different and represent hydrogen, alkyl, substituted alkyl or acyl, and R.sub.1,R.sub.2 and R.sub.3 are the same or different and represent hydrogen, halogen, alkyl, alkoxy, amino, nitro, carboxyl or sulphonyl, in the presence of peroxidase.

Abstract: Disclosed is a method for the colorimetric determination of hydrogen peroxide in a sample by reacting a particular chromogen with the hydrogen peroxide in the presence of peroxidase and measuring the absorbancy of the reaction solution in the visible ray region. Also disclosed is a test composition for carrying out the determination.

Abstract: This invention relates to an improved process for preparing N-carboxylic anhydrides of amino acids, and N-carboxylic anhydrides of derivatives of amino acids by reacting an amino acid, a derivative of amino acid or a salt thereof with trichloromethylchloroformate in an organic solvent, preferably a mixture of an ether or ester with one or more other organic solvents and adding to the reaction mixture carbon, basic aluminum chloride or aluminum oxide just before or immediately after completion of the initial reaction.