Everything about Heme Oxygenase totally explained
Heme oxygenase (HO) is an
enzyme that
catalyzes the degradation of
heme. This produces
biliverdin,
iron, and
carbon monoxide.
Reaction
Heme oxygenase cleaves the heme ring at the alpha-methene bridge to form either biliverdin or, if the heme is still attached to a
globin,
verdoglobin. Biliverdin is subsequently converted to
bilirubin by
biliverdin reductase.
The reaction occurs as follows:
» :
Image:Heme.svg |heme
Image:Biliverdin.png|biliverdin
This reaction can occur in virtually every
cell; the classic example is the formation of a
bruise, which goes through different colors as it gradually heals: red heme to green biliverdin to yellow bilirubin. Under normal physiological conditions, the activity of heme oxygenase is highest in the
spleen, where old
erythrocytes are sequestrated and destroyed.
Isoforms
There are three known
isoforms of heme oxygenase.
Heme oxygenase 1 (HO-1) is an inducible isoform in response to stress such as oxidative stress,
hypoxia,
heavy metals,
cytokines, etc. Heme oxygenase 2 (HO-2) is a constitutive isoform which is expressed under homeostatic conditions. Both HO-1 and HO-2 are ubiquitously expressed and catalytically active.
A third heme oxygenase (HO-3) isn't catalytically active, but is thought to work in oxygen sensing.
Further Information
Get more info on 'Heme Oxygenase'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://heme_oxygenase.totallyexplained.com">Heme oxygenase Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |