User:TheLarry/Notebook/Larrys Notebook/2010/08/23

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Rate Constants

Yesterday i reported that my model was not following the proper michaelis menten kinetics. at low atp the velocity stayed high. So it was unbinding quickly but taking a step or so keeping the velocity high. it is possible that the kinesin needs to waste more time before disassociating, but i am not sure. today i am gonna go over rate constants that are not in my pdf file that josey helped me compile

Monomer

  • Interacting Head Mechanism of Microtubule-Kinesin ATPase, Ma and Taylor
    • ADP binding: 1.5 [math]\displaystyle{ \mu M^{-1}s^{-1} }[/math]
    • ADP dissociation: [math]\displaystyle{ 110 s^{-1} }[/math]

ADP binding

  • Inhibition of kinesn motility by ADP and phosphate supports a hand over hand mechanism, Scheif et al
    • [math]\displaystyle{ .25 \mu M^{-1} s^{-1} }[/math]

Michaelis-Menten

i know why michaelis menten doesn't work. it's because when ATP concentration is low the system goes towards a state of ADP/ADP and in our set up that is basically gonna unbind quickly and then step. since its step is equal in either direction this will probably average out over the long term, but since there is no slow rate this happens quickly thus increasing the velocity. i'm not sure what to do about it.

also all my constants look good except 1. it is aphosphate release. and i don't know how to fix it