1. Dismiss Notice
  2. This forum is for support and discussion only. Please promote test prep materials/services (including AMAs) in the Special Offers subforum only. Thanks!
    Dismiss Notice
  3. Guest, be sure to check out How To Get Into Dental School, our free downloadable PDF with step-by-step details for dental school applicants!
    Dismiss Notice

Methemoglobin question

Discussion in 'DAT Discussions' started by dragon72, Dec 7, 2005.

  1. dragon72

    dragon72 Junior Member

    Joined:
    Dec 7, 2005
    Messages:
    8
    Likes Received:
    0
    question: why the conversion from normal hemoglobin to methemoglobin causes the dissociation curve to shift left instead of right. If it shift left then affinity for oxygen would increase and that is wrong. I don 't understand why.

    Thanks in advance,
    Andy
     
  2. IndDent

    IndDent || Bharat Maata Ki Jai ||
    5+ Year Member

    Joined:
    Aug 29, 2005
    Messages:
    174
    Likes Received:
    0
    where is this question from? If your talking about myoglobin -stuff found in muscle- then yes myoglobin is to the left of hemoglobin on the oxygen dissociation curve. Meaning, that myoglobin has a higher affinity for oxygen than hemoglobin. So when hemoglobin comes into the areas of the muscle, it transfers oxygen to myoglobin.

    Hope that helps. I've never heard of nor seen methemoglobin before.
     
  3. rpkall

    rpkall Darwin Award Winner
    7+ Year Member

    Joined:
    Sep 25, 2004
    Messages:
    531
    Likes Received:
    9
    I think when one heme (of one of the chains) is in an Fe3+ state, the molecule "acts" as if that heme is oxygenated (exhibiting cooperativity; even though there's really no O2 there)--and this increases the affinity of that hemoglobin molecule for oxygen in the other three binding sites. The curve shifts to the left, and because the molecules have such a high affinity for oxygen, unloading to tissues is impaired.

    I think. ahahaha :thumbup:
     

Share This Page