title: A modified ferrous oxidation-xylenol orange assay for lipoxygenase activity in rice grains.
abstract: Ferrous oxidation-xylenol orange assay reagent was reformulated by using spectral analysis of ferric-xylenol orange complex to detect low concentrations of lipoxygenase rice grain products. Reducing the levels of ferrous sulphate and xylenol orange in the FOX reagent enabled the detection of low concentrations of hydroperoxy fatty acid derived from lipoxygenase activity in the range of 0.1-1.5 μM. Protein, substrate and time courses of the modified FOX assay were studied to determine lipoxygenase activity in rice grain. The assay was also applicable as a high throughput technique for comparisons of lipoxygenase activity from various rice varieties. This has important implications for rapid screening for low-lipoxygenase containing rice cultivars in rice breeding program and grain quality during storage.
authors.affiliation: Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Tarinee
authors.initials: T
authors.lastname: Timabud
authors.forename: Jirawat
authors.initials: J
authors.lastname: Sanitchon
authors.forename: Paweena
authors.initials: P
authors.lastname: Pongdontri
mesh_terms: D002523:Edible Grain / Q000737:chemistry / Q000201:enzymology; D057075:Enzyme Assays / Q000379:methods*; D005296:Ferrous Compounds / Q000737:chemistry*; D008084:Lipoxygenase / Q000032:analysis*; D012275:Oryza / Q000737:chemistry / Q000201:enzymology*; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry*; D010940:Plant Proteins / Q000032:analysis*; D013454:Sulfoxides / Q000737:chemistry*
chemical_list: D005296:Ferrous Compounds; D010636:Phenols; D010940:Plant Proteins; D013454:Sulfoxides; C020748:ferrous sulfate; D008084:Lipoxygenase; C016833:xylenol orange
keywords: Ferrous oxidation-xylenol orange (FOX) assay; Hydroperoxy fatty acid product; Lipoxygenase; Rice grain