Haemaglobin and Myoglobin Flashcards
What is the structure of haem?
Protoporphyrin ring
Fe2+ bound to four nitrogen atoms of that ring
How many bonds is Fe2+ in haem capable of forming?
Six
What are the two additional bonds that Fe2+ in haem makes?
Bound to globin chain
Bound to oxygen
What shape is the proporyphyrin ring?
Planar
What is the spatial arrangement of Fe2+ in the protoporphyrin ring?
Fe2+ sits slightly below the plane of the protoporphyrin ring
What is the spatial arrangement of the two additional bonds that Fe2+ in haem forms, compared to the protoporphyrin ring?
At right angles to the protoporphyrin ring
What happens to the spatial arrangement of Fe2+ in the protoporphyrin ring when it binds to oxygen? How does this affect the globin protein?
Fe2+ moves up into the plane of the protoporphyrin ring
pulls up globin chain
gives small conformational change in haemaglobin
What type of secondary structure does myoglobin have?
Mostly alpha helical
What type of tertiary structure does myoglobin have?
Mostly globular
What is the name of the graph of x axis-pO2 against y axis-% saturation?
Oxygen binding curve
What is pO2?
Partial pressure of oxygen
What is P50?
Partial pressure of oxygen that gives 50% saturation
What shape does the oxygen binding curve for myoglobin take?
Rectangular hyperbola
What type of tertiary structure does haemaglobin have?
Globular
What type of quaternary structure does haemaglobin have?
Tetramer of
- 2 alpha globin chains
- 2 beta globin chains
How many haem groups are there in haemaglobin?
Four