Hemoglobin and myoglobin

hemoglobin And
Myoglobin
Presented By: Abdul Basit (42512)
Usama Aamir (41585)
Presented To: Dr. Asma Abro

2
Contents
Introduction
Structure Of hemoglobin And Myoglobin
Functions Of hemoglobin And Myoglobin
Comparison Between hemoglobin And Myoglobin
Cooperativity and Allosteric Regulation in hemoglobin
Conclusions
References

3
Introduction
Because of its red colour, the red blood pigment has been of interest since antiquity.
First protein to be crystallized - 1849.
First protein to have its mass accurately measured.
First protein to be studied by ultracentrifugation.
First protein to associated with a physiological condition.
First protein to show that a point mutation can cause
problems.
First proteins to have X-ray structures determined.
Theories of cooperativity and control explain hemoglobin
function

4
Pathway
Lungs hemoglobin Myoglobin
O2
O2
Tissue

5
hemoglobin
 heme(Blood)-Globin(Protein)
 heme is a prosthetic group
 Only Fe++ Binds Oxygen
 α2 β2 Heterotetramer
 Transport Protein
Myoglobin
 Myo(Muscle)-Globin(Protein)
 Storage Protein
 Monomer (Single Polypeptide Chain)

6
Structure of hemoglobin And Myoglobin
heme
N α Chain
Chain β N
N β Chain
N α Chain

9
Functions of hemoglobin And Myoglobin
During this process, the hemoglobin
macromolecule undergoes conformational
changes due to the binding and unbinding of
oxygen and carbon dioxide. And it include :
Oxygen Pickup
Oxygen Delivery
Carbon Dioxide Pickup
Carbon Dioxide Delivery

Comparison
Myoglobin
 Myoglobin is a globular protein.
Water soluble.
Ligand is oxygen.
Myoglobin exist in muscle(tissue).
Myoglobin is a storage protein.
hemoglobin
hemoglobin is also a globular protein.
Water soluble.
Ligand is oxygen.
hemoglobin exist in blood.
Hemoglobin is a transport protein.
11

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Myoglobin hemoglobin
 Bind And Release O2 to muscle
cell.
 Monomer (Single polypeptide
Chain)
 8 Helices segments
 Tertiary Structure
 Histidine is present helps to
attach with Fe (Iron)
 Take O2 From lungs to the tissues
(Including Muscles)
 Oligomeric nature ( More than one
polypeptide chain)
 Actually made up of 2 α and 2 β side
chains
 Quartnery structure
 Also Attaches with histidine residues
to impart some kind of buffering
properties to blood

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Myoglobin hemoglobin
 Higher affinity towards oxygen
because myoglobin needs to grab
the oxygen from hemoglobin.
 Can bind to one heme group
(prosthetic group).
 Comparatively lower affinity
towards oxygen
 hemoglobin have two states
 R state (Oxyhemoglobin) And T
state (Deoxyhemoglobin)
 Can Bind to 4O2 Molecules each
subunit has a heme group.

14
Cooperativity
 A simple phenomenon in which when one oxygen is bind to one
subunit the affinity for O2 at the other subunit increases.
Allosteric regulation
 Simply, binding of one ligand to a subunit will affect on the affinity
of other subunits.

16
Conclusion
 Animals Have Widely Varying O2 Need
 hemoglobin and Myoglobin are Related, but Have Different Functions
 hemoglobin has Four Subunits and heme group.
 Myoglobin has One of Each Bind of O2 by heme’s Iron Pulls up on a Histidine and
Change’s hemoglobin Shape Changing hemoglobin Shape Converts hemoglobin from
T-state to R-state
 R-state Binds Oxygen Better.
 T-state Releases O2 Better
 Sickle Cell Anaemia (SCA) is a Genetic Disease of hemoglobin.

References
17
Oxygen binding by myoglobin & hemoglobin. (2004, October 1). Retrieved
from https://www.bio.cmu.edu/courses/03231/LecF04/Lec13/le
c13.html
Bucci, E., Razynska, A., Kwansa, H., Gryczynski, Z., Colli ns, J. H., &
Fronticelli, C. (1996). Positive and negative cooperativities at subsequent
steps of oxygenation regulate the allosteric behavior of multistate
sebacylhemoglobin. Biochemistry, 35, 3418 - 3425

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