Haemoglobin

• what is the mr of haemoglobin?

  64,400
• what type of protein is haemoglobin?

  tetrameric
• how many subunits does haemoglobin have?

  4, each contain a haem group with its Fe2
• what is an allosteric regulator?

  influence effect of oxygen
• what is the tetramer made up of?

  two alpha identical and 2 beta identical chains
• what way are the subunits packed?

  in a tetrahedral array
• what is the difference between haemoglobin and myoglobin?

  myoglobin carries charged amino acids at position which are hydrophobic
• what does urea do?

  breaks apart multimeric proteins
• what does urea dissolve haemoglobin into?

  two alpha-beta dimers
• what are the names of the identical alpha-beta diamers?

  alpha 1 beta 1 and alpha 2 and beta 2
• how are the alpha beta dimers held together?

  strong contacts with each other
• what does Hb transport?

  H+ and Co2 as well as o2
• what are the 3 allosteric regulators?

  H+, co2 and 2,3-bisphosphoglyverate (2,3-BPG)
• how do allosteric regulators work?

  reduces capacity for hb to bind to oxygen
• where is 2,3-BPG produced?

  during glycolysis
• what is the p50 of haemoglobin?

  26.6 torr
• saturation of hb

  
• what does a sigmoidal shape mean?

  binding is cooperative
• which binds oxygen tighter my or hb?

  my
• what is cooperative?


  A single transport binds to the next is easier
• what does cooperative mean for hb releasing oxygen?

  Once it has released one oxygen molecule, it gets easier to release another and this increases as another one is released
• What occur is hb is without any allosteric regulators?

  Binds oxygen too tightly for phyisological needs
• what does a movement of the curve to the right?

  oxygen is bound less tightly
• what do allosteric regulators do to the blood?

  weaken oxygen affinity to enable hb to unload oxygen more easily
• which allosteric regulator has a greater effect on oxygen affinity co2 or 2,3-BPG?

  2,3-BPG
• when is lactic acid formed?

  Acidification of venous blood from dissolution of co2 and its subsequent ionisation
• what occurs to blood ph during exercise?

  Decrease
• as ph decrease oxygen affinity...

  decrease
• what is the concentration of 2,3-BPG?

  4-5 mM
• where does 2,3-bpg bind?

  Only binds to deoxyhaemoglobin between 2 beta subunits of hb.

  Only one 2,3-bpg binds to and haemoglobin tetramer
• What occurs to 2,3-bpg in the lungs?

  high oxygen conc so is removed, as hb is no longer deoxyhaemoglobin
• does foetal haemglobin more or less tightly to oxygen than normal adult haemoglobin?


  More
• what is the significance of foetal hb binding more tightly to oxygen?


  can take up oxygen from mother blood
• what occurs as you increase the temperature to oxygen affinity of hb?


  causes a shift to right so releases o2
• why might there be an increase in temperature for oxygen release?

  active muscles
• what influences hb levels?

  iron levels - important for functionality of hb

  Exercise

  erythropoietin - stimulates hb production
• how much does the distance between iron and beta chain change in oxygenation?


  from 3.99nm (deox) to 3.34nm (oxy)
• what is deoxyhaemoglobin also known as?

  tense state
• what is deoxyhaemoglobin constrained by?

  hydrophobic bonds and 8 electrostatic bonds
• what do the electrostatic bond do in deoxy?


  holds it in place