Tredwell Flashcards
Explain hemoglobins R state and T state
R- state has high O2 affinity and T-state has low O2 affinity
decreasing pH affects Hb oxygenation curve how?
shifts right
increasing pCO2 affects Hb oxygenation curve how?
shifts right
increasing conc of DPG affects Hb oxygenation curve how?
shifts right
what is the origin of cooperative binding in Hemoglobin?
the oxy-state Fe(III) centre moving with Histidine, triggering conformational change in the protein
2 functions of hemoproteins
- 6 coord Fe with diaxial ligands doesn’t react with oxygen
- Encapsulation of the heme prevents irreversible oxidation
Hemerythrin is what
Fe dinuclear protein responsible for O2 storage and transport in marine invertebrates
Hemocyanin is what
Copper dinuclear protein responsible for O2 storage and transport in arthropods and molluscs
how does cisplatin act?
enters by passive diffusion, hydrolyses to [Pt(NH3)2Cl(OH2)]+ and reacts with DNA
How does the Pt of Cisplatin bind to DNA?
binds to the N7 atoms of guanosine and adenosine
Why does cisplatin bind to N7 on A and G?
higher pKb of N7 and is in the major groove, so is accessible
What does Au(I) react with?
Soft nucleophiles - eg thiols, glutathione, metallothioneins and human serum albumin
explain inactivation of hemoglobin by CO
CO tricks Hb into mistaking it for oxygen, binds to Hb in groups of 4, changing Hb-O equilibrium. Equilibrium shifts to the right and Hb puts priority on CO bonds
how does fetal Hb compare to Hb?
Has a higher affinity for O2, has a lower affinity for 2,3-DGP and a different structure
How does 2,3-DPG lower O2 binding to Hb?
Binds to the centre cavity of deoxyhemoglobin (electrostatic interaction of negative DPG and positively charged His group) and stabilises the T state (decreasing O2 affinity)
