title: A new peroxidase color reaction: oxidative coupling of 3-methyl-2-benzothiazolinone hydrazone (MBTH) with its formaldehyde azine. Application to glucose and choline oxidases.
abstract: Hydrogen peroxide in the presence of horseradish peroxidase effects the oxidative coupling of 3-methyl-2-benzothiazolinone hydrazone with its formaldehyde azine to form a tetraazapentamethine dye. The blue chromophore, when formed at pH 3.5 and quenched with acetone or 1 N hydrochloric acid, has an extinction coefficient of 69 +/- 2 or 55 +/- 2 mM-1 cm-1, respectively. This chromogen system has been adapted for enzymatic determinations of hydrogen peroxide and of glucose in the 10- to 45-nmol range and of choline in the 5- to 20-nmol range.
mesh_terms: D000429:Alcohol Oxidoreductases; D052160:Benzothiazoles; D002794:Choline / Q000032:analysis; D003124:Colorimetry; D004396:Coloring Agents; D005947:Glucose / Q000032:analysis; D005949:Glucose Oxidase; D006835:Hydrazones; D010084:Oxidation-Reduction; D010544:Peroxidases; D013844:Thiazoles
chemical_list: D052160:Benzothiazoles; D004396:Coloring Agents; D006835:Hydrazones; D013844:Thiazoles; D000429:Alcohol Oxidoreductases; C019888:choline oxidase; D005949:Glucose Oxidase; D010544:Peroxidases; D005947:Glucose; D002794:Choline; C002536:3-methyl-2-benzothiazolone hydrazone