Abstract: A method for measuring concentration of dehydrogenase and substrate thereof in the presence of living cells, wherein an electron mediator that is hard to be reduced by living cells, for example, a compound represented by Formula (I), an electron mediator represented by the Formula (I) and a measurement reagent for dehydrogenase and substrate thereof including the electron mediator are disclosed. A-L-M??(I), wherein A represents a structural part containing at least one anionic group, M represents a structural part for mediating electron transfer and L represents a linker part for linking the A to the M.

Abstract: A method for measuring concentration of dehydrogenase and substrate thereof in the presence of living cells, wherein an electron mediator that is hard to be reduced by living cells, for example, a compound represented by Formula (I) shown below, an electron mediator represented by the Formula (I) shown below and a measurement reagent for dehydrogenase and substrate thereof comprising the electron mediator are disclosed. A?L?M ??(I) [In the Formula (I), A represents a structural part containing at least one anionic group, M represents a structural part for mediating electron transfer and L represents a linker part for linking the A of the M.

Abstract: Tetrazolium salt compounds represented by the following general formula (1): ##STR1## wherein R.sup.1 and R.sup.2 independently represent hydrogen atom, nitro group, cyano group, carboxyl group or a halogen atom, preferably nitro group; R.sup.3 represents an alkyl group or an alkoxyl group, preferably methyl group or methoxy group; and M represents an alkali metal or an ammonium. The compounds are useful for quantitative measurement of a dehydrogenase, and characterized to have high water-solubility and excellent storage stability in the state of an aqueous solution.

Abstract: A diagnostic marker containing (a) a detection system such as an antibody and (b) a fluorescent functional group that is bound to the detection system and represented by the following formula: ##STR1## wherein R.sup.1 and R.sup.2 independently represent hydrogen atom, an alkyl group or the like; R.sup.3 represents an alkyl group, a sulfonic acid-alkyl group or the like; X.sup.- represents an anion species, if required; Y represents a C.sub.1 -C.sub.10 alkylene group or a C.sub.1 -C.sub.10 alkylene group containing one or more atoms selected from the group consisting of oxygen atom, nitrogen atom and sulfur atom. The diagnostic marker emits fluorescence having a wavelength of 780 nm or more when irradiated with near or far infrared rays, and thus useful for infrared endoscopic diagnosis or identification of a focus in surgical operation.

Abstract: An object of the present invention is to inhibit the influence of the reducing substances on the oxidative coloring reaction in biological components.A constitution of the present invention is that a compound having the free radical of the general formula (1) ##STR1## is previously added to the biological sample and then an incubation is carried out.An effect of the present invention is that the influence of the reducing substances on the oxidation reaction can be inhibited and, even when no reducing substance is present, there is no effect on the oxidation reaction.

Abstract: Method for detecting peroxidase or hydrogen peroxide with high sensitivity. Both peroxidase and hydrogen peroxide are prepared such that one of them is overabundant to the other. Phenoxy radicals are produced from a p-substituted phenol compound by the action of peroxidase in the presence of hydrogen peroxide. The free radicals are trapped by a hydroxy amine compound, and stable radical species are produced. Electron spin resonances of the stable radical species are measured.