Description
Introduction: Heme oxygenase (HO) is a microsomal enzyme that catalyzes the oxidation of heme to the antioxidant molecules, biliverdin and carbon monoxide. HO consists of two homologous isozymes, an inducible HO1 and a constitutively expressed HO2. HO1 is induced by a wide variety of stimuli including conditions of oxidative stress, inflammatory agents, transforming growth factor beta and heat shock. The increase in expression of HO1 is thought to be a cellular defense mechanism against oxidative stress since elevated HO could eventually generate more bilirubin, an anti-oxidant. HO1 expression is greatly increased in neurofibrillary tangles in Alzheimer's disease and other neurodegenerative diseases such as progressive supranuclear palsy and subacute sclerosing panencephalitis.
Principle of the Assay: The microtiter plate provided in this kit has been pre-coated with an antibody specific to HO-1. Standards or samples are then added to the appropriate microtiter plate wells with a biotin-conjugated antibody preparation specific for HO-1 and Avidin conjugated to Horseradish Peroxidase (HRP) is added to each microplate well and incubated. Then a TMB (3,3',5,5' tetramethyl-benzidine) substrate solution is added to each well. Only those wells that contain HO-1, biotin-conjugated antibody and enzyme-conjugated Avidin will exhibit a change in color. The enzyme-substrate reaction is terminated by the addition of a sulphuric acid solution and the color change is measured spectrophotometrically at a wavelength of 450 nm +/- 2 nm. The concentration of HO-1 in the samples is then determined by comparing the O.D. of the samples to the standard curve