title: Enzymatic method for selective determination of 4-aminobenzoic acid in urine.
abstract: We developed a method for the selective determination of 4-aminobenzoic acid by use of 4-aminobenzoate hydroxylase (EC 1.14.13.27) to convert 4-aminobenzoic acid to 4-hydroxyaniline. The subsequent conversion of 4-hydroxyaniline to indophenol dye was quantified colorimetrically. The method is reproducible, and the assay response is linear up to 40 mumol/L. Selectivity exceeding that of the current colorimetric assays was demonstrated for these enzymatic determinations of 4-aminobenzoic acid concentrations in urine samples from patients undergoing tests of pancreatic function with bentiromide. This method effectively minimizes interferences from drugs and diet, a problem in current colorimetric methods.
authors.affiliation: Department of Nutrition, School of Medicine, University of Tokushima, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Bando
authors.forename: T
authors.initials: T
authors.lastname: Ogawa
authors.forename: H
authors.initials: H
authors.lastname: Tsuji
authors.forename: K
authors.initials: K
authors.lastname: Sasaoka
mesh_terms: D010129:4-Aminobenzoic Acid / Q000378:metabolism / Q000652:urine*; D003124:Colorimetry / Q000379:methods; D006801:Humans; D006899:Mixed Function Oxygenases
chemical_list: D006899:Mixed Function Oxygenases; C050092:4-aminobenzoate hydroxylase; D010129:4-Aminobenzoic Acid