Daiichi Pure Chemicals Co., Ltd.

Masahiro Sekiguchi

Hiroyuki Ebinuma

Koji Ushizawa

Takuji Matsumoto

Toshikatsu Abe

Takami Sarashina

The present invention provides a method for quantitatively determining a reducing substance, which comprises reacting a reducing substance in a test specimen with iron (III) ions, reacting iron (II) ions formed by reduction of the iron (III) ions or residual iron (III) ions with a metal indicator which is capable of reacting specifically with the iron (II) ions or the residual iron (III) ions to undergo color development, and carrying out quantitative determination by measuring the degree of color development, wherein a chelating agent which is specific to copper ions is added to the test specimen before the reaction of the reducing substance with the iron (III) ions; and a reagent used for it.

Method for quantitatively determining a reducing substance and a reagent for quantitative determination

The present invention provides a method for quantitatively determining homocysteine in a biological specimen containing homocysteine and cysteine by use of an enzyme which is capable of forming hydrogen sulfide both from homocysteine and from cysteine, which comprises (a) reacting the biological specimen with cysteine dioxygenase in the absence of a reducing agent, (b) subsequently reacting the resultant specimen of (a) with a reducing agent and the enzyme which is capable of forming hydrogen sulfide both from homocysteine and from cysteine, and (c) measuring the concentration of the hydrogen sulfide thus obtained to determine the homocysteine concentration in the biological specimen; and a reagent for such a quantitative determination of homocysteine.

Method for quantitatively determining homocysteine and a reagent for quantitative determination of homocysteine

An air-barrier agent for an aqueous reagent or an aqueous specimen having as an effective component a mixture of a chain hydrocarbon and a silicone oil immiscible with the aqueous reagent as well methods of using and making the same.

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Ryugasaki, Japan

Masahiro Sekiguchi