03 Hemoglobin

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  • component of RBC, carries O2

  • blue and red: globin chains

  • green: heme, 4 in a hemoglobin

Globin

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  • sickle cell: abnormal hemoglobin

Heme

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  • porphyria: defects in enzymes making the porphyrin

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  • RBC with BPG Mutase makes 2, 3 BPG

  • bad for red cells: sacrifices ATP (pyruvate normally used to make ATP)

Hemoglobin Binding

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  • favored in tissues to release O2. T for tissues

  • relaxed form favored in lungs to pick up more O2

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  • myoglobin: bind each O2 molecule equally, linear increase until plateau

  • hemoglobin: S shaped curve. Hard to bind first one and then speeds up

  • example of allosteric effect

Allosteric Effects

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CO

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  • loses cooperativity

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MetHB

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  • rest of Fe2 binds O2 with higher affinity, left shift curve

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  • methylene blue reduces Fe3 to Fe2

  • vitamin C reduces Fe3 to 2

  • SOB from methemoblobinemia

  • interferes with pulse ox

  • normal amount of O2 in blood

CN

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  • functional hypoxia: enough O2 around but can't use them

  • inhibits cytochrome oxidase a3

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