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S08.02

Zoe Fernyhough Inglés 18 fichas

Fichas del conjunto (18)

1metHbOxidation of Heme -> hemin
Fe3+ (ferric state) instead of Fe2+ --> cannot bind O2!!!
2Methemoglobinemialower O2 transport
caused by nitrites, drugs
3Mb structure8 alpha helices (75% of chain) linked by loops
nonpolar side chains make heme pocket
4O2 binding in HbH bonding between O2 and His
5Hb structure4 subunits of Mb
6Fractional saturation of O2 (molar)
7Fractional saturation of O2 (pressure)Y is frac. saturation!
8Calculating partial pressure of a gas
9Higher p50 value --> ?lower O2 binding affinity
P50 is pressure of O2 needed for 50% saturation
10Hb cooperative bindingsigmoidal curve, binding of one O2 increases affinity for more O2 binding
Dissociation decreases affinity for O2 so more is delivered
11Mb binding curveHyperbolic, no coop binding bc binds only 1 O2 molecule
12p50 Mb and Hbp50 Mb: 2 torr
p50 Hb: 26 torr
13Hb bindingCooperative --> sigmiodal! (S shaped) steep in middle
always less saturated than Mb
14Hb delivered to tissueproportional to difference in Y
deltaY = Y artery - Y vein
15degree of cooperativitymin: 1, max: # binding sites/ moleculle
16R state HbR: relaxed, Fe in plane of heme, higher O2 affinity
17T state HbT: tense, Fe out of plane and not as available for O2 binding
18O2, HbT, HbR relationO2 binds R state subunit, R and T in rapid equilibrium, and causes neighboring subunits to turn to R. breaks ion pairing between subunits