Difference between SDS Page and gel electrophoresis in Non-reducing condition?

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sen117
Posts: 12
Joined: Fri Jan 10, 2020 2:51 pm

Difference between SDS Page and gel electrophoresis in Non-reducing condition?

Post by sen117 » Tue Feb 18, 2020 5:21 pm

Hi,

1. Could you please help me distinguish the following?
    SDS-PAGE remove non-covalent inter-bond & eliminate conflation from m/z ratio
      Gel Electrophoresis Non-reducing condition: break inter-bonds btw proteins except covalent bond (disulfide bond).

      They seem to have the same function. What is the difference?

      2. Regarding Bohr's Law, could you confirm if my logic is correct in understanding how the Hb graph moves toward the right in acidic conditions? Is it wrong to think in terms of Km? Since high Km is equivalent to Low affinity of E-S, I think it makes sense the graph moves to right as high CO2 or H+ decrease the Hb's affinity toward O2 (increase Km).


      Thank you so much for your help in advance! =)
      NS_Tutor_Mathias
      Posts: 616
      Joined: Sat Mar 30, 2019 8:39 pm

      Re: Difference between SDS Page and gel electrophoresis in Non-reducing condition?

      Post by NS_Tutor_Mathias » Thu Feb 20, 2020 2:33 pm

      1. You are correct, SDS-PAGE if not otherwise specified is how we run non-reducing gels. Technically we might use other non-reducing denaturing agents, so 'non-reducing gel' is a broader group than just SDS-PAGE.

      2. It does happen in the literature and it is not incorrect to use the affinity constant for hemoglobin's interaction with oxygen. Particularly if you are well aware that hemoglobin is neither acting enzymatically nor following Michaelis-Menten kinetics, which are the conditions that you would normally be discussing affinity constants on the MCAT. It may however be safer to say that the dissociation curve shifts rights - because the affinity of hemoglobin for oxygen shifts not just with pH, but with important things like the occupation of cooperative binding sites, local partial pressure of oxygen and concentration of 2,3-BPG.

      Your understanding otherwise is correct. A decrease in pH decreases the affinity of hemoglobin for oxygen. This works out nicely because this decrease of pH is fueled by the carbonic anhydrase catalyzed formation of carbonic acid from CO2, a waste product of glucose metabolism. Meaning more remaining bound oxygen can be freed when metabolic activity is high and demand for oxygen threatens to outstrip the blood's ability to supply it.
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