Heme oxygenase-1 (HO-1) is a microsomal enzyme that degrades heme, a prosthetic group of the heme protein family (e.g. hemoglobin), into the bile pigment biliverdin. Biliverdin is subsequently converted to bilirubin, carbon monoxide and reduced iron. Bilirubin has an anti-inflammatory effect and is part of the oxidative stress response in the body due to its strong free radical scavenging activity, whereas carbon monoxide has a vasodilatory effect on organ blood flow.
Heme oxygenase exists in at least two isozyme forms, heme oxygenase-1 and heme oxygenase-2, each of which differs in its tissue expression and inducibility. HO-1 in particular is intracellularly induced as part of the oxidative stress response; therefore, HO-1 monitoring may prove useful for the identification of physiological stress inducers.
The Rat Heme Oxygenase-1 EIA Kit (Precoated) is a 96-well format in vitro enzyme immunoassay kit intended for the quantitation of rat heme oxygenase-1 in rat blood, cell culture supernatant and various organ systems. It is a solid phase sandwich heme oxygenase-1 (HO-1) ELISA that utilizes two mouse monoclonal HO-1 antibodies, one of which is coated on the plate and the other of which is peroxidase-labeled. Detection of rat HO-1 occurs via a two-step incubation method: In the first step, experimental samples are incubated in the antibody-coated microtiter plate. During the second step, the plate is washed and incubated with the peroxidase-labeled HO-1 antibody. The reaction between the peroxidase and the substrate (H2O2, TMBZ) results in color development. The amount of sample HO-1 is determined by measuring signals using an EIA absorbance plate reader. Accurate HO-1 sample concentrations can be determined by comparing their absorbances to the absorbance generated for the supplied standard (via a plotted standard curve).