Let's Do Science! :D

Oh hey everyone. I have a Biochemistry final exam tomorrow. It's 10.47pm now and I'm kinda like in my sleepy phase. If I read the notes I'm gonna end up sleeping therefore I shall write it in my blog!!! Just to share with you and to bypass my sleepy phase. When it's over my bedtime then I'll be active again. So here goes! Our topic tonight is Transport of Oxygen and Carbon Dioxide. I purposely chose this topic to write in this blog because I'm sure everyone will understand this compared to other topics which will make you guys go crazy. Anyway, I'm gonna write it short and simple ok. Enjoy!

Myoglobin
- 77% alpha helix, 23% random coil
- eight helices: A B C D E F G H

• interior residues are non-polar (hydrophobic) except His E7 and His F8
• exterior residues are both polar and non-polar

- contains a heme cofactor:

• porphyrin ring and Fe2+
• required for protein folding and oxygen binding (oxygen binds the Fe2+)

- monomer

- high affinity for oxygen

- unaffected by pH, conc of CO2, conc of BPG

- binds 1 oxygen

- hyperbolic oxygen saturation curve 

- store oxygen only

Hemoglobin

- Four subunits (tetramer):

• 2 alpha subunits (alpha globin chain)
• 2 beta subunits (beta globin chain)
• Best described as a dimer of a heterodimer

- Each alpha and beta subunits looks like myoglobin

- Main difference between Hb and Mb is due to Hb quaternary structure:

• Cooperative binding to oxygen
• Allosteric regulation by CO2, H+ and BPG

- Synthesized in RBC precursor cell: reticulocytes and erythroblasts

- Synthesis is controlled by the concentration of heme

- High proportion of alpha helix: 75% of the amino acid is associated with 8 alpha helices

- alpha helices are organized into tightly packed, nearly spherical and globular tertiery structure

- Highly soluble: polar amino acid in the exterior surface

- Each globin contains one noncovalently bound heme group

- tetramer

- moderate affinity for oxygen

- affected by pH, conc of CO2, conc of BPG

- binds 4 oxygen

- sigmoidal oxygen saturation curve

- transport oxygen (store and release)

Ok I give up. There's too much to write. Bye!