Abstract: Cholesterol in low-density lipoprotein (LDL) or very low-density lipoprotein (VLVL) in a sample is determined in the presence of a sugar compound and/or a protein-solubilizing agent.

Abstract: Provided are a method of determining the amount of cholesterol in high-density lipoprotein (HDL), which comprises measuring the amount of cholesterol in low-density lipoprotein (LDL), very-low-density lipoprotein (VLDL) and chylomicron (CM) in a sample in the presence of a sugar compound and/or a protein solubilizing agent, and calculating the difference between the amount of cholesterol in LDL, VLDL and CM and the total amount of cholesterol in the sample, and a method of determining the amount of cholesterol in HDL, which comprises measuring the amount of cholesterol in HDL in a sample in the presence of a sugar compound and/or a protein solubilizing agent.

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 method for determination of an analyte in a sample containing reducing substances is disclosed. After the decomposition of the reducing substances by reaction with hydrogen peroxide formed by enzymatic Redox reaction using a component in the sample which does not participate in another enzymatic Redox reaction using the analyte, the remaining hydrogen peroxide is decomposed, and then the analyte is subjected to enzymatic Redox reaction to form hydrogen peroxide which is then determined by a known method.

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 ceruloplasmin activity, wherein a member selected from the group consisting of (a) ferrocene or derivatives thereof (b) metallocene and (c) chelate metal containing iron or copper is reacted with a chromogen in the presence of ceruloplasmin to form colored material which is determined photometrically, as well as a reagent suitable therefor.

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: Cholinesterase activity is determined by means of the choline and/or acid obtained by the action of cholinesterase on a compound of the formula: ##STR1## [wherein A represents a hydrogen atom or a C.sub.1-5 alkyl or alkoxy group and B represents a group of the formula --R-COO-- (in which --R-- represents an alkenyl group with 2 to 6 carbon atoms); or A represents a hydroxy group in either or both o-positions of the benzene ring or a C.sub.1-5 alkyl group and B represents a group of the formula --COO--; X represents a stabilizing anion and n represents the charge on the anion]. The method of the invention ensures a high resistance to saturation, good stability of the compounds used as substrates, a conveniently low reaction rate and a high degree of accuracy.Certain of the compounds of formula I as defined above are novel compounds which are claimed per se.Examples of the method of the present invention are given and the preparation of the novel compounds is described and exemplified.

Abstract: A method of and reagent for determining hydrogen peroxide, in which the hydrogen peroxide containing sample is treated with a colouring reagent comprising a peroxidase, a hydrogen donor and an electron or radical acceptor which react stoichiometrically with the hydrogen peroxide to produce a pigment which is then measured colorimetrically. In accordance with the invention the hydrogen donor is specifically a compound of the formula ##STR1## where R.sub.1 is CH.sub.3, C.sub.2 H.sub.5, CH.sub.2 OH, CH.sub.2 CH.sub.2 OH, CH.sub.2 CH.sub.2 NH.sub.2 or COCH.sub.3 ;R.sub.2 is CH.sub.2 OH, CH.sub.2 CH.sub.2 OH, CH.sub.2 CH.sub.2 NH.sub.2, CH.sub.2 NHCOCH.sub.3, CH.sub.2 CH.sub.2 NHCOCH.sub.3 or COCH.sub.3 ;R.sub.3 is H, CH.sub.3, C.sub.2 H.sub.5 or OCH.sub.3 ; andR.sub.4 is H or CH.sub.3.

Abstract: Phospholipid content in a sample is quantitatively determined by enzymatically converting the phospholipids into choline and then determining the amount of the choline.