Dojindo Laboratories

Dojindo Molecular Technologies, Inc.

Makoto Mizoguchi

Kazumi Sasamoto

Masanobu Shiga

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.

Method of inhibiting the activity of the reducing substances in

An oxidative chromogenic reagent free from interference by bilirubin used for the measurement of a biogenic substance by an enzymatic analysis, which comprises a compound or a salt thereof represented by the following formula wherein R.sup.1 and R.sup.2 independently represent a C.sub.3-4 -alkly group substituted with a sulfonic acid group or a C.sub.3-4 -hydroxyalkyl group substituted with a sulfonic acid group; and R.sup.3 and R.sup.4 independently represent a C.sub.1-4 -alkyl group, a C.sub.1-4 -alkoxy group, a substituted or non-substituted carbamoyl group, an acyl-substituted amino group, an aryl group, or a halogen atom. The reagent is stable and has excellent water solubility, and it enables high sensitive and accurate measurement because interference by bilirubin is substantially reduced or eliminated. ##STR1##

Assay using oxidative chromogenic reagent

Novel water-soluble methylenebis(dialkylaniline) derivatives of the following general formula and salts thereof are disclosed. They are useful as dye-forming substances in quantitative determination of peroxides in the copresence of peroxidase or the like. ##STR1## In the formula, R.sub.1 is hydrogen or a substituent selected from lower alkyl and C.sub.2-3 sulfoalkyl or hydroxysulfoalkyl; R.sub.2 is C.sub.2-3 sulfoalkyl or hydroxysulfoalkyl; and R.sub.3 is lower alkyl.

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Kumamoto, Japan

Makoto Mizoguchi