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SURVEY OF BIOCHEMISTRY
Protein Function
1
O2 Binding to Hemoglobin
Hill Equation: Derive on board
log
Y
1-Y
= n log (pO2) - n log p50
Cooperativity: binding of a ligand to one site affects
the binding of other ligands to other sites.
Hill Constant
Cooperativity
n=1
No cooperativity (hyperbolic)
n>1
Cooperative binding
n<1
Noncooperative binding
2
Allosteric Interactions
T state without O2
R state with O2
T -> R transition
causes structural
changes!
See 7-1D
3
Bohr Effect Enhances O2 Transport
As pH 
O2 affinity
in Hb 
4
Bohr Effect and O2 Transport
5
BPG Binds to T-State of Hb Only
6
Proteins in Muscle Contraction
• Thick filament: Myosin
• Thin filament:
– Actin
– Troponin
• Ca2+-binding protein
• Binds to both tropomyosin and actin
– Tropomyosin binds to actin
7
Muscle Protein Structure
Complex
Myosin
Globular
head group
Long, fibrous
alpha-helical
tail
8
Force Generation in Muscle
9
Force Generation in Muscle
10
Force Generation in Muscle
11
Force Generation in Muscle
12
Force Generation in Muscle
13
Force Generation in Muscle
14
Immunity
• Cellular (T cells)
– Viruses
– Fungi
– Parasites
– Foreign Tissue
• Humoral (B cells)
– Bacteria
– Extracellular Viruses
T cells develop
in thymus
Antibodies develop in
B cells which
mature in bone marrow
15
Immunoglobins
16