Haemoglobin and Heamoglobinisation Flashcards
What is the molecular mass of H?
64-65.5 kDA
Why is both haem and globin essential?
Haem is important for O2 transport, while globin serves to protect haem from oxidation; renders the molecule soluble and permits variation in O2 affinity.
What are the three phases of haemoglobinisation?
Embryonic, foetal and adult.
What makes the haemoglobin different during the different phases?
The globin chains.
Which 2 chromosomes are responsible for globin syntheses?
11 and 16
What four things incl a globin chain does chromosome 11 code for?
Beta globin, ɛ , 𝝲, ẟ
epsilon, gamma, delta
What 2 things does chromosome 16 code for?
Alpha globin, 𝝵 (zeta)
How many different types of h are there?
7 - A, A2, F, G1, G2, P1, P2
Which globin chains are synthesised by the 5th week of gestation in primitive erythroblasts?
ZE - zeta and epsilon, with the production of G1, G2, P1 and P2
Which globin chains are synthesised from week 6 on?
ABG - alpha, beta and gamma.
Which H is in the embryo is essential for life and why?
G2
Inability to produce H A which is incompatible with life.
Where is H synthesised in the 10-12 weeks of gestation?
In the liver and the spleen with the production of F and later HA
What proportion of HA is in a normal healthy adult?
~97%
What proportion of HA 2 is in a normal healthy adult?
~2.0 - 3.3%
What proportion of H F is in a normal healthy adult?
~0.2 - 1%
How much iron per mg/kg is in the male body?
50mg/kg
How much iron per mg/kg is in the female body?
35mg/kg
How is the majority of the body’s iron stored/which form?
65% - Haemoglobin
30% - Ferritin and its insoluble Hemosiderin in macrophages, marrow, liver, spleen
How is iron found in the cells?
In cytochrome enzymes in cells.
What is iron bound to ?
The iron transport protein in the blood; transferrin.
How much iron is absorbed based on a western diet of 10-15mg of iron daily?
5-105 is absorbed.
What are the two forms of haem ?
Haem and Non-haem forms in ferrous ++ and ferric +++ states.
Which is the more easily absorbed type of iron in food?
The ferrous , it is absorbed more rapidly than the ferric form.
Which enzyme facilitates the release of haem iron in the gut?
Haemoxygenase 1
Which form is non-haem iron usually found?
In the Ferric +++ form
Which enzymes facilitates the conversion of ferric iron to ferrous iron for easier absorption?
Ferroreductase
What does the haem molecule consist of?
- Protoporphyrin ring
- iron molecule in centre
- 4 pyrrole groups united by methan bridges
What is free iron absorbed by?
Enterocytes in the gut, via a specific cell membrane called the Dimetal trasnporter-1 (DMT 1)
What does ferroportin do and what manages it?
Ferroportin is on the surface of enterocytes and has a role in the export of iron into circulation.
Hepcidin
What does hepcidin do?
It manages the level of ferroportin, increase or decrease - role in the amount of iron being transferred into circulatory system.
Which iron transport protein transports iron over the brush border in the gut?
Transferrin molecule.
What are the names of the iron stores in the tissue macrophages?
Ferritin and hemosidirin.
Where is iron primarily absorbed?
In the duodenum and the upper jejunum where acidic conditions help the absorption.
Which reducing substances aid iron absorption?
HCL and Ascorbic acid.
What are the 3 main causes for losses of body iron?
- menstruation
- GI bleeds
- epithelial cells from skin, gut or urinary tract
What are the names of the three IRON CARRIER PROTEINS which bring free iron to the liver for synthesising?
Albumin
Lactoferrin
Transferrin ** n.b
Why is transferrin (76-80kDA) the most important iron carrier?
It can carry 2 atoms of ferric iron.
Transferrin is then reutilised to pick up more free iron in the body.
