Description
The human Heme Oxygenase 1 (HO-1) is an enzyme that catalyzes the degradation of Heme, leading to the production of biliverdin, ferrous iron, and carbon monoxide. HO-1 is an isoform induced in response to stress such as oxidative stress, hypoxia, heavy metals, cytokines, etc. The human Heme Oxygenase bles the fast monitoring of HO-1 produced by cells.
HTRF assays offer many advantages over other technologies:
Homogeneous add-and-read format
No wash steps
Low background
Straightforward miniaturization from 96- or 384-well microplates to high density assay formats such as 384-well low volume and 1536-well plates
Stable signal, providing flexibility in time of readout or size of assays
Assay principle
Human heme oxygenase is measured using a sandwich immunoassay involving two specific human heme oxygenase antibodies, respectively labelled with Europium Cryptate (donor) and d2 (Acceptor). The intensity of the signal is proportional to the concentration of heme oxygenase present in the sample.
Assay Protocol
The human heme oxygenase kit features a two-plate assay protocol, where cells are plated, stimulated, and lysed in the same culture plate. Lysates are then transferred to the assay plate for the detection of Human HO-1. This protocol enables the cells' viability and confluence to be monitored. The antibodies labelled with HTRF fluorophores may be pre-mixed and added in a single dispensing step to further streamline the assay procedure. The assay detection can be run in 96- to 384-well plates by simply resizing each addition volume proportionally.
Human Heme Oxygenase standard curve
A two-fold serial dilution starting from 25 ng/ml of Human Heme-Oxygenase-1 protein was performed, and fitted with with the 4 Parameter Logistic (4PL) model (with 1/Y² weighting). This data must not be substituted for the data obtained in the laboratory and should be considered only as an example.
Heme Oxygenase production in HEPG2 cells
HEPG2 cells were plated at 50,000 cells per well and were stimulated for 6H in the presence or absence of 10 µM of Cadmiumchloride. After removing the supernatant, the cells were lysed using the lysis buffer provided in the kit, and diluted 5 times before plating. The labeled antibodies from the kit were then added. The plate was read after 4 hours. A 2.9 fold increase of the HTRF ratio over non-stimulated cells was observed, exemplifying the production of human HO-1 after Cd-ion stimulation.
