BIBC 100 Handout 5

BIBC 100 Handout 5 - BIBC 100 Structural Biochemistry...

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Unformatted text preview: BIBC 100 Structural Biochemistry Handout 5 (Lecture 13) Mimi Nguyen mmnguyen@ucsd.edu OH Fri 10:30–11:30am 1st Floor S&E Hb Oxygen Binding • Hb goes from low O2 affinity ______________ to high O2 affinity ______________ as more O2 is bound o • • As O2 is released from Hb, the binding affinity ______________ and more O2 is easily released by the other subunits Bohr Effect: O2 Association Curve o The O2 binding curve shifts to the _____________ as pH decreases Hb has an inverse affinity to O2 and H+ • • When [O2] ______, Hb binds O2 and releases H+ When [O2] ______, Hb binds H+ and releases O2 This ion-pair forms, stabilizing the _______________ ______________ O2 affinity and more O2 released into the As pH decreases in Hb, HisHC3 ______________________ with AspFG1 • o In the tissues ______ pH and ______ [CO2] tissues o In the capillaries (lungs) ______ pH and ______ [CO2] • 2,3 Bisphosphoglycerate (BPG) Lehn Fig. 5.17 o o o • Binding occurs in the __________________ BPG will _________________ the affinity for O2 by stabilizing the _________________ At higher altitude [BPG] increases. Why? ______________ O2 affinity and more O2 is bound to Hb Sickle Cell Anemia o o o o A single amino acid substitution: ________ ________ (E6V) HbS Fibers (B & T Fig. 3.14) The hydrophobic residue fits perfectly into hydrophobic pocket Increased resistance to malaria Sickle forms in deoxy T-state at capillaries, making it harder to transport O2 • Carbon Monoxide Poisoning o o o Lehn Box 5-1 CO is a colorless, odorless gas that binds to Hb with a greater affinity than O2 Anemia vs. CO poisoning Anemic Hb are more ready to release O2 because CO has a higher affinity than O2 to Hb, so anemic Hb will still deliver O2 whereas CO-Hb will not dissociate as easily and therefore no O2 transport will occur. 1 ...
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This note was uploaded on 01/02/2010 for the course BIBC BIBC 100 taught by Professor Buehler during the Fall '09 term at UCSD.

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