Description
Haemoglobin, the oxygen-transport protein in the red blood cells, is a tetramer and each of the four chains
contains a haeme group. It is interesting to note that the four haeme groups in haemoglobin do not operate
independently. The release (and binding) of oxygen is a cooperative process, which means that the loss
(uptake) of the first oxygen molecule triggers the release of the remaining three.
The current model for oxygen binding in haemoglobin and myoglobin can be explained in the following
way. The deoxy form contains a high-spin Fe(II) centre, which, because of its size, does not form a plane with
its four nitrogen donor atoms. Instead, it is located slightly above the plane, drawn towards the His residue.
Once oxygen enters trans to the His residue, the iron centre is oxidised to a low-spin Fe
3+ centre and O
2 is
reduced to [O
2]
-. Both species contain an unpaired electron. The low-spin Fe
3+ moves into the plane and
pulls the His residue down. This affects the remaining protein chain and triggers the uptake/release of oxygen
in the other three haeme groups.
Uses
Medicine, usually called hemoglobin.
Uses
Hemoglobin is the most important respiratory protein of vertebrates by virtue of its ability to transport oxygen from the lungs to body tissues, and to facilitate the return transport of carbon dioxide. It is used as a coloring agent for pet foods, a natural source of iron for nutraceuticals, a protein source for non-ruminant animals, and as a raw material for pharmaceutical porphyrin derivative production.
Uses
Hemoglobin from bovine blood has been used in:
- standard curve generation for the quantification intraparenchymal hemorrhage and parenchymal hemorrhage in spinal cord homogenate using Drabkin′s assay, Quadrupole-Ion Mobility-Time-of-Flight mass spectrometery
- the generation of molecularly imprinted polymers (MIPs) to mimic high molecular-weight polyethylene glycol (PEG) in crystallization studies
Definition
The respiratory protein of the red blood cells, it transfers oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs. Its affinity for carbon monoxide is >200 times that for oxygen. Hemoglobin is a conjugated protein of molec
Definition
One of a group ofglobular proteins occurring widely inanimals as oxygen carriers in blood.Vertebrate haemoglobin comprisestwo pairs of polypeptide chains,known as α-chains and β-chains(forming the globin protein), witheach chain folded to provide a bindingsite for a haem group. Each ofthe four haem groups binds oneoxygen molecule to form oxyhaemoglobin.Dissociation occurs inoxygen-depleted tissues: oxygen is releasedand haemoglobin is reformed.The haem groups also bind other inorganicmolecules, including carbonmonoxide (to form carboxyhaemoglobin).In vertebrates, haemoglobinis contained in the red blood cells(erythrocytes).
Definition
The pigment of the red
blood cells that is responsible for the transport
of oxygen from the lungs to the tissues.
It consists of a basic protein, globin,
linked with four heme groups. Heme is a
complex compound containing an iron
atom.
The most important property of hemoglobin
is its ability to combine reversibly
with one molecule of oxygen per iron atom
to form oxyhemoglobin, which has a
bright red color. The iron is present in the
divalent state (iron(II)) and this remains
unchanged with the binding of oxygen.
There are variations in the polypeptide
chains, giving rise to different types of hemoglobins
in different species. The binding
of oxygen depends on the oxygen partial
pressure; high pressure favors formation of
oxyhemoglobin and low pressure favors
release of oxygen.
General Description
Native hemoglobin from bovine erythrocytes. A major oxygen-transporting component of red blood cells that is also nitric oxide scavenger. Blocks carbachol-stimulated cGMP production. This preparation contains primarily Ferric-hemoglobin and must be reduced to the ferrous form to bind molecular oxygen.
Note: this preparation contains primarily ferric-hemoglobin and must be reduced to the ferrous form to bind molecular oxygen.
Biochem/physiol Actions
The Fe2+/Fe3+ balance is a physiological indicator of blood oxygenation. Deoxygenated hemoglobin accessorizes a feedback loop by reducing nitrite to NO, a vasodilator which enhances blood flow to oxygen-deprived tissues.
Purification Methods
Purify it from blood using CM-32 cellulose column chromatography. [Matsukawa et al. J Am Chem Soc 107 1108 1985.] For the purification of the and chains see Hill et al. Biochemical Preparations 10 55 1963. Histones (from S4A mouse lymphoma). The purification of histones uses a macroprocess column, heptafluorobutyric acid as solubilising and ion-pairing agent and an acetonitrile gradient. [McCroskey et al. Anal Biochem 163 427 1987.]
