Myoglobin and Hemoglobin Flashcards
what does a large ka value mean for binding
its mean a tight binding
what does a small kd mean for binding ?
if kd less than 10 nM its strong binding
what are 3 key things about O2 transport
- o2 must be able to diffuse through tissue
- oxidative metabolism coverting food to energy
3 . removal of co2 from lungs
what are 2 things in similarity for myo globin and hemoglobin
- each subunit binds one iron containing a heme group
- the heme group is bound in a hydrophobic pocket
what is myoglobin made up out of and where is it found ?
its found in muscle tissue
a monomeric protein
153 AA single polypeptide
can go up to tertiary
whats myoglobins function ?
it carries out o2 storage and transport it within the muscle and increase the solubility and diffusion rate of o2 in cell and tissue
what is hemoglobin made up out of and where is it found ?
found in red blood cells
its it a tetrameric a2b2 protein
a subunit 141 AA , B subunit 143 AA
can go up to quaternary
has 4 oxygen binding sites
what is hemoglobins function ?
it functions to transport o2 to tissues from lungs and co2 to lungs from tissues
what is the heme ?
it is the oxygen binding site where iron is bound first then oxygen binds
what 2 things does the iron atom bind at the side of both hemoglobin and myoglobin
its binds both oxygen and histadine
what are the conditions at the heme so oxygen can bind
oxygen must bind at an angle or else the oxygen willl oxidize the iron and leave making the iron non functional
how can we measure 02 binding
as the heme groups is a strong chromophore is absorbs ultra violet and the visible range through UV spectrophotmetry changes in fe starte show changes in absorbance
what type of o2 binding curves does myglobin and hemoglobin have
mb has a hyperbolic curve (log curve)
hemoglobin has a sigmodial curve (like s curve)
what is the partial pressure of o2 ?
the measure of o2 dissolve in aq sln inside the cell or blood
what happens to 02 binding at low po2 and high po2 in myglobin
oxygen stays bound from like 3 po2 past 13 kpa along a long range of po2
how is hemoglobin a good transport protein
through cooperatvity as it has multiple binding sites it they all interact with each otheer as it increase affinity of the other sites
for hemoglobin what happens at low po2 and what happens at high po2
it has a lower affinity for o2 falls off easier
at high po2 it have a higher affinity for o2 and binds more easily
what is T (tense) state
the hemoglobin conformotion in the de oxy state where there is low affinty binds poorly
what is the R (relaxed) state
the hemoglobin conformation. in the oxy state where it has high affinity binds well
how does positive cooperativity work with T and R state for hemoglobin (hb)
the binding to the first or two binding spots during t state is diffult but once both bound it converts to high affinity r state
what is an effector
is it a molecule or ion tha binds to protein or enzyme and changes it activity can decrease or increase affinity
what 3 things decrease o2 affinity
1, the acidity in our blood
2. binding of co2 at n terminius of hb
3. small molcules like BPG in blood stream
what is the bohr effect and what causes it
increasing acidity that shift the hb binding curve to the right as metabolism release co2 and protons which lower ph
where do the bohr protein bind ?
they bind during the t state of hb at the b chain c terminus and n terminal of a chain
