title: An improved spectrophotometric assay for histamine and diamine oxidase (DAO) activity.
abstract: Diamine oxidase or its substrates can be measured using a coupled reaction with peroxidase and the chromogen 3-methyl-2-benzothiazolone hydrazone (MBTH) with an appropriate acceptor such as 3-(dimethylamino)benzoic acid (DMAB). This method provides a more rapid and sensitive method of measuring histamine than current colorimetric assays; using this system, histamine was quantitated at concentrations of 10 to 400 mumol/l. The Km of DAO was determined to be 2.9 X 10(-5) M, a lower value than previously reported.
mesh_terms: D006631:Amine Oxidase (Copper-Containing) / Q000032:analysis*; D052160:Benzothiazoles; D002863:Chromogenic Compounds; D006632:Histamine / Q000032:analysis*; D006835:Hydrazones; D006863:Hydrogen-Ion Concentration; D013053:Spectrophotometry / Q000379:methods; D013844:Thiazoles
chemical_list: D052160:Benzothiazoles; D002863:Chromogenic Compounds; D006835:Hydrazones; D013844:Thiazoles; D006632:Histamine; D006631:Amine Oxidase (Copper-Containing); C002536:3-methyl-2-benzothiazolone hydrazone