03 Hemoglobin - Boards and Beyond

  • component of RBC, carries O2
  • blue and red: globin chains--- date: 2021-03-20

03 Hemoglobin

  • related:
  • green: heme, 4 in a hemoglobin

Globin

  • sickle cell: abnormal hemoglobin

Heme

  • porphyria: defects in enzymes making the porphyrin

  • RBC with BPG Mutase makes 2, 3 BPG
  • bad for red cells: sacrifices ATP (pyruvate normally used to make ATP)

Hemoglobin Binding

  • favored in tissues to release O2. T for tissues
  • relaxed form favored in lungs to pick up more O2

  • 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

CO

  • loses cooperativity

MetHB

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

  • 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

  • functional hypoxia: enough O2 around but can't use them
  • inhibits cytochrome oxidase a3