Hb and retinoal binding

• What is the effect of temperature increase on the oxygen dissociation curve.

  
  

  The curve shifts to the right, increasing the release of O2
• What is the main changes upon oxygenation of Hb.

  Distance between iron atoms in Beta-chains decreases.
• What state is Deoxyhaemoglobin

  The Tense State
• What state is Oxyhaemoglobin

  The Relaxed State
• What bonds are present within deoxyheamoglobin [T].

  • Hydrophobic bonds
  • 8 electrostatic bonds
• Where does Oxygen bind in Hb

  
  

  • Binds to the 6th coordinate position of the Iron atom
• Describe the conformational change upon Oxygen binding

  • Iron atom is pulled down towards the protoporphyrin IX plane
  • The iron atom pulls Histadine F8 with it
  • 8 electrostatic bonds are broken
  • Alpha-beta dimers rotate by 15 degrees
  • Beta-subunits are closer and so 2,3-BPG is NOT bound [Relaxed state]
• What is Retinol

  One of several active forms of Vitamin A
• What is Retinol made from

  • Derived from β-carotenes synthesised by plants
• Describe the structure of the Retinol Binding Protein (RBP)

  
  

  • 8 Anti-parallel B-sheets
  • The retinol binding site is lined with hydrophobic residues
• What is the order of oxygen transport molecules at low partial pressure.

  Highest affinity: Myoglobin

  Middle affinity: Foetal

  Lowes affinity: Heamoglobin
• Where is retinol made

  Liver
• What transports retinol

  Retinol-binding protein
• What are the main roles of Vitamin A

  • Anti-oxidant
  • Steroid-hormone
  • Night vision