[thedy]

Is Michaelis-Menten model valid only,when we talk about initial rate of reaction?

I have a problem to understand it,because,everywhere in books,articles on net is Michaelis-Menten equation used only for initial rate.And I m asking,with Michaelis-Menten can I determine only initial rate or any other as well,which I want to determine?Or why is initial rate used in Michaelis-Menten equation?
Thanks a lot for your time

[Borek]

[ S] is a function of time, so if you can calculate it, you can use MM equation to calculate rate at any other moment. I suppose usually we assume we know the initial S concentration, but we don't know what happens later.

Note that MM equation is derived with some simplifying assumptions and is only approximate, if you need precise rate values, you can be better off solving the full set of differential equations describing your system.