Hemoglobin & Myoglobin Flashcards
Tetrameric polypeptide mainly utilized for oxygen transport
Hemoglobin
The phenomenon that permits hgb to maximize both the quantity of O2 at the pO2 of the lungs and the quantity of O2 released at the pO2 of the peripheral tissues
Cooperative binding
Hemoglobin is what kind of protein?
Functional
By product of respiration
CO2
Stabilizes the T-structure of Hgb
2-3 BPG
Planar, slightly puckered, cyclic tetrapyrrole
Heme
Reciprocal coupling of H+ and O2 binding
Bohr effect
Mutations of Hgb that compromises biologic function
Hemoglobinopathies
Transition from T state to R state are influenced by? (4)
Protons, Carbon Dioxide, Chloride, BPG
True or false: release of O2 at the peripheral tissue is accompanied by the uptake of proton due to he lowering of pka of histidine residues
True
Genetic defects in the globin synthesis of hgb
Alpha and beta Thalassemias
Treatment for CO poisoning
O2 theraphy
Small molecules that binds to a protein at a site other than the catalytic site
Allosteric effectors
It’s tertiary structure is a water soluble globular protein
Myoglobin
Tetrameric protein composed of two pairs of alpha subunit and gamma subunit
Hbf
The iron atom lies in the center of this
Protoporphyrin
Fully saturated quaternary structure of oxygenated hemoglobin
R-state
when there an increase in pKa what would be the effect on the hemoglobin dissociation curve?
Shift to the right = decreased O2 affinity
Unit if pressure equal to that exerted by a column of mercury 1mm high at 0 degree celsius and standard gravity
Torr
True or false: the strength of HbCO bond is less than the HbOxy bond
True - because the distal E7 histidine hinders the bonding of CO at the preferred 90 deg angle to the plane of the heme ring.
Hemoglobin that can neither bind nor transport O2
Methemoglobin
Normal HbA1c for diabetic patients
Less than 7%
Increase in ph = ___ in oxygen affinity
Increase
Intracellular storage site for oxygen
Myoglobin
Key enzyme in Bohr effect
Carbonic anhydrase
Responsible for the distinctive red color of blood
Heme
Why does HbF binds less to 2,3 BPG than HbA?
Because the residue h21 of the gamma subunit of HbF is Ser which does not form a Salt Bridge. HbF has a higher affinity for O2 than HbA
Distal histidine
His E7 or His 64
Proximal histidine
His F8 or His 93
Oxygen binding curve of Hgb
Sigmoidal curve
This is released during O2 deprivation
Myoglobin
Is is the set of fetal beta globin gene within the beta globin cluster
Gamma genes / beta gamma genes
Effective CO3 transport process is referred to as
Isohydric transport
What is the role of the Chloride ion Shift in the transport of CO2 and Bohr Effect
Maintains electrical neutrality - Homeostasis
True or False: high pH is ideal for the formation of salt bridges.
False - because at high ph the side chain of histidine beta 146 is not protonated and the salt bridge does not form
The alpha and beta globin genes are found on what chromosomes?
Alpha - chromosome 16
Beta - chromosome 11
2 types of hemoglobinopathies
Qualitative abnormalities - eg. Sickle cell anemia
Quantitative abnormalities - eg. Thalassemia
Major Hgb at the embryonic development within the yolk sac
Hb Gower 1 (2 zeta, 2 eta)
Increase on hydrogen ion concentration = ______ amount of oxygen bound to hemoglobin
Decrease
A form of CO2 transported in the blood as a dissolved gas formed with the amino terminal nitrogens of the polypeptide chain 15% of CO2 in the body is transported this way.
Carbaminohemoglobin or carbhemoglobin or carbohemoglobin
Caused by a single nucleotide substitution of valine for glutamate at position 6 on the beta subunit of hemoglobin
Sickle cell anemia
Methemoglobin or hemoglobin M can arise from decrease activity of what enzyme?
Methemoglobin reductase
