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Solving enzyme reaction and diffusion

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Hi,
I am trying to solve a reaction diffusion problem. It is time dependent and I am expecting to get at t=0 the concentration of product at point d=0. My initial concentration of product is 0. There is a generation of product Rsp= Vmax as in my system S >>> Km.
I am attaching my problem here. Kindly let me know how this issue can be resolved.
Thanks!


7 Replies Last Post 5 août 2015, 07:01 UTC−4

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Posted: 9 years ago 4 août 2015, 05:27 UTC−4
According to what I understood from your problem set-up, I attach here my solution. Note that substrate is initially everywhere at concentration S but is consumed in the reaction. The distances are so small that the entire space is filled with product rather quickly.

BR
Lasse
According to what I understood from your problem set-up, I attach here my solution. Note that substrate is initially everywhere at concentration S but is consumed in the reaction. The distances are so small that the entire space is filled with product rather quickly. BR Lasse


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Posted: 9 years ago 4 août 2015, 07:13 UTC−4
Hi Lasse,
I cant open the file, its in later version.
Hi Lasse, I cant open the file, its in later version.

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Posted: 9 years ago 4 août 2015, 09:04 UTC−4
Which version do you have?
Which version do you have?

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Posted: 9 years ago 4 août 2015, 10:04 UTC−4
I have COMSOL 4.4
I have COMSOL 4.4

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Posted: 9 years ago 4 août 2015, 12:03 UTC−4
I made a report of the model. It is not very clear, if I may say so, but I have two variables c1 (product) and c2 (substrate) which diffuse in the entire domain [0,L]. The reaction takes place in the domain [0,d]. At x = 0 and x = L I have No Flux condition. At point x = d no BC is needed at all, neither another separate Convection and diffusion node. I deactivated convection, so it does not appear at all in the node.

Reaction Rsp = Vmax*c2/(Km + c2); it must be defined as a variable under Component Definitions, not global. I deleted all variables under Global Definitions.

I used time stepping 0,10^{range(-6,0.2,0)} because the reaction rate is at highest in the beginning.

Wish this helps
Lasse
I made a report of the model. It is not very clear, if I may say so, but I have two variables c1 (product) and c2 (substrate) which diffuse in the entire domain [0,L]. The reaction takes place in the domain [0,d]. At x = 0 and x = L I have No Flux condition. At point x = d no BC is needed at all, neither another separate Convection and diffusion node. I deactivated convection, so it does not appear at all in the node. Reaction Rsp = Vmax*c2/(Km + c2); it must be defined as a variable under Component Definitions, not global. I deleted all variables under Global Definitions. I used time stepping 0,10^{range(-6,0.2,0)} because the reaction rate is at highest in the beginning. Wish this helps Lasse


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Posted: 9 years ago 5 août 2015, 06:58 UTC−4
I need at x=d there should be a flux(P) and concentration(P) continuity. I don't need a boundary condition for that?

I need at x=d there should be a flux(P) and concentration(P) continuity. I don't need a boundary condition for that?

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Posted: 9 years ago 5 août 2015, 07:01 UTC−4
No. Comsol assumes continuity of fluxes and concentrations unless you deliberately wish to change it. That could be due to, say, partitioning between the aqueous and organic phases.
No. Comsol assumes continuity of fluxes and concentrations unless you deliberately wish to change it. That could be due to, say, partitioning between the aqueous and organic phases.

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