Lecture notes
Iron in the body - Biochemistry
- Module
- Biology (BIO4000)
- Institution
- Bath Spa University (BSU)
Here are lecture notes for a biochemistry lecture on iron in the body
[Show more]
Seller
Follow
Content preview
BIOCHEMISTRY – LECTURE 11 PART 2iron in the body
Iron is vitally important in many molecules – oxygen binding proteins (haem
prosthetic group) = haemoglobin and myoglobin, electron transport chain
proteins and in many enzymes = haem-based iron centre and non-haem-based
iron (sulfur based) such as ETC.
Iron is in the ‘d block’. It is a transition element. Like all transition elements it is a
metal that has multiple oxidation states (variable valency). Transition elements
(including iron) have their characteristics because of the complexity in the filling
of electron shells above 3p (4s shells are occupied before 3d, and are lost first).
This contributes to the multiple, stable oxidation states and characteristic
different colours at these states. At pH 7 and above, iron is usually found in the
3+ (ferric) state, whereas at acidic conditions is typically found in the 2 + state
(ferrous).
Although the redox promiscuous nature of iron is vital for many of its functions, it
presents potential problems:
In 3+ state will form large complexes with anions and precipitate out of
solution
Free iron binds to molecules and can affect their function
Free iron is also used by some bacteria and can allow for pathological
microbial proliferation
The body has many iron-binding proteins to protect it from these
dangerous effects.
Fe2+ can catalyse the cleavage of the O-O bond in hydrogen peroxide to produce
hydroxyl radical and a hydroxide ion. This is known as the Fenton reaction.
Hydroxyl radicals are more damaging than superoxide.
Fe2+ + H2O2 HO· + HO- + Fe3+
Superoxide can react with the hydroxyl radical to form singlet oxygen and
although technically a termination step, the resultant 1O2* is reactive.
O2·- + HO· 1O2* + HO-
Generally, radicals react with other molecules by free-radical substitution, in a
chain reaction of reduction/oxidation. The chain reaction or propagation effect
explains why radicals are so damaging, even at low concentrations.
The haem prosthetic group is made of a tetrapyrrole ring with the iron ion in the
middle. 4 of these prosthetic groups are incorporated into the haemoglobin
protein. Haemoglobin is a tetramer; it consists of two α-globin chains and two β-
globin chains.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller lucygodbeer. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £5.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
67866 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now