Abstract: Provided is a measuring method of a component to be measured in a specimen while suppressing an influence of bilirubin. A measuring method of a component to be measured, comprising converting the component to be measured in the specimen to hydrogen peroxide through an enzymatic reaction, reacting the formed hydrogen peroxide with an oxidative-coloring chromogen in the presence of a peroxidase, and measuring an absorbance of the colored reaction solution to thereby determine the component to be measured, wherein a fatty acid or a salt thereof coexists. The measuring method of a component to be measured in a specimen according to the present invention is useful in clinical diagnosis.

Abstract: Provided is a method for simply and accurately measuring sphingomyelin in a sample, and a kit therefore. The method is a method for measuring sphingomyelin in a sample, comprising reacting the sample with a phospholipase D which does not react with sphingomyelin and lysophosphatidylcholine but reacts with phosphatidylcholine, a lysophospholipase or a monoglyceride lipase, and a choline oxidase, eliminating the formed hydrogen peroxide, reacting the resultant with a phospholipase D which does not react with glycerol-3-phosphorylcholine and free fatty acid but reacts with sphingomyelin, and a choline oxidase, and measuring the formed hydrogen peroxide.

Abstract: Provided is a measuring method of a component to be measured in a specimen while suppressing an influence of bilirubin. A measuring method of a component to be measured, comprising converting the component to be measured in the specimen to hydrogen peroxide through an enzymatic reaction, reacting the formed hydrogen peroxide with an oxidative-coloring chromogen in the presence of a peroxidase, and measuring an absorbance of the colored reaction solution to thereby determine the component to be measured, wherein a fatty acid or a salt thereof coexists. The measuring method of a component to be measured in a specimen according to the present invention is useful in clinical diagnosis.

Abstract: Provided is a method for simply and accurately measuring sphingomyelin in a sample, and a kit therefor. The method is a method for measuring sphingomyelin in a sample, comprising reacting the sample with a phospholipase D which does not react with sphingomyelin and lysophosphatidylcholine but reacts with phosphatidylcholine, a lysophospholipase or a monoglyceride lipase, and a choline oxidase, eliminating the formed hydrogen peroxide, reacting the resultant with a phospholipase D which does not react with glycerol-3-phosphorylcholine and free fatty acid but reacts with sphingomyelin, and a choline oxidase, and measuring the formed hydrogen peroxide.

Abstract: A method for measuring cholesterol in low-density lipoprotein contained in a sample, which comprises reacting a sample with (i) a combination of cholesterol ester hydrolase and cholesterol oxidase or (ii) a combination of cholesterol ester hydrolase, an oxidized coenzyme and cholesterol dehydrogenase in the presence of: [a] a polyoxyethylene-polyoxyalkylene alkylaryl ether; [b] one or more surfactants selected from the group consisting of a polyoxyethylene-polyoxyalkylene copolymer, a polyoxyethylene alkenyl ether, a polyoxyethylene branched alkyl ether, and a polyoxyethylene-polyoxyalkylene branched alkyl ether; [c] one or more surfactants selected from the group consisting of a primary amine, a secondary amine, a tertiary amine, and a quaternary ammonium; and [d] a polyanion, and measuring a substance formed or consumed in the reaction.

Abstract: A method for measuring cholesterol in low-density lipoprotein contained in a sample, which comprises reacting a sample with (i) a combination of cholesterol ester hydrolase and cholesterol oxidase or (ii) a combination of cholesterol ester hydrolase, an oxidized coenzyme and cholesterol dehydrogenase in the presence of: [a] a polyoxyethylene-polyoxyalkylene alkylaryl ether; [b] one or more surfactants selected from the group consisting of a polyoxyethylene-polyoxyalkylene copolymer, a polyoxyethylene alkenyl ether, a polyoxyethylene branched alkyl ether, and a polyoxyethylene-polyoxyalkylene branched alkyl ether; [c] one or more surfactants selected from the group consisting of a primary amine, a secondary amine, a tertiary amine, and a quaternary ammonium; and [d] a polyanion, and measuring a substance formed or consumed in the reaction.