Allosteric interaction

[yjj8817]

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How does this change km but not vmax? Is hemoglobin becoming more attracted to oxygen when one oxygen binds a good example of this? Thanks!

 

[erythrocyte666]

other way around - allosteric changes Vmax but not Km --> conformational change at active site causes enzyme's catalytic ability to change but not it's binding affinity to substrate. and yeah, hemoglobin's cooperative binding can seen as example of allosteric activation

 

[Cawolf]

Also of note is that 2,3 BPG allosterically inhibits hemoglobin's affinity for oxygen.

 

[yjj8817]

other way around - allosteric changes Vmax but not Km --> conformational change at active site causes enzyme's catalytic ability to change but not it's binding affinity to substrate. and yeah, hemoglobin's cooperative binding can seen as example of allosteric activation

But it says in ek that "all allosteric inhibitors and activators are not necessarily noncompetitive inhibitors because many alter km without affecting vmax"

 

[yjj8817]

Also of note is that 2,3 BPG allosterically inhibits hemoglobin's affinity for oxygen.

And CO2 too!

 

[erythrocyte666]

But it says in ek that "all allosteric inhibitors and activators are not necessarily noncompetitive inhibitors because many alter km without affecting vmax"

hmm...guess most are
never saw a difference; but for the few allosteric inhibitors that are NOT noncompetitive, this shows a good explanation: http://forums.studentdoctor.net/thr...teric-inhibition-whats-the-difference.942798/