Hemoglobin/Myoglobin Flashcards
What are Globins?
A superfamily of proteins containing the globin fold of 6-8 alpha helixes arranged in a characteristic HEME-enclosing structure
Which Type of Iron is normal in heme?
Fe2+
Fe3+ leads to production of superoxides
What is the p50 value? What is fractional saturation?
p50 = the PO2 at which 50% of th3 binding sires are occupied
Y is fractional saturation = # sites occupied / # sites
What is the p50 of Myoglobin?
~ 3 Torr (mmHg)
What is the p50 for Hb?
~26 Torr
What is the hill equation, and how can it show cooperativity?
Log (Y/1-Y) = n(log[pO2] - log[p50])
N = Hill Coefficient
N = 1 No cooperativity
N > 1 Positive Cooperativity
N < 1 Negative Cooperativity
What is the maximum Hill coefficient value?
Max = # Subunits
What affect does pH have on the Hb/O2 binding Curve?
Decreased pH Shifts curve to the right and Visa Versa
What factors increase O2 delivery/absorption and shift the O2 dissociation curve to the right?
- pH decrease
- [CO2] increase
- 2,3-BPG increase
- Temperature increase
Why does 2,3BPG affect O2-Hg binding?
It binds to Deoxy Hb and prevents O2 binding
What activity does Nitrite facilitate with Hemoglobin.
Acts as a mathemoglobin reductase and converts Hb(Fe3+) —> Hb(Fe2+)
What regulatory properties does NO have?
- Vasodilation
- Inhibition of Smooth muscle
- Proliferation and migration
- Antiplatelet effects
What happens to hemoglobin during development?
During weeks 12-40 (Birth), is mostly alpha-gamma Hb. In First 12 weeks, it is replaced with alpha-Beta Hb
What role could Hb have in Glaucoma?
- Hb is a common radical scavenger and helps with nitric oxide detoxification
- May serve as a protective mechanism in retinal ganglion cells to prevent glaucomatous neurodegenration
What are two newly discovered globins?
- Cytoglobin
- Neuroglobin
