Enzyme kinetics

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ManBearPig89
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Enzyme kinetics

Post by ManBearPig89 » Sun May 30, 2010 11:28 am

Hello! I have a question about enzymes...

When looking at the [S] and comparing it to Vmax, does this mean that Vmax is the point when an enzyme can no longer take in any more substrate (moles/ secound?) in it's active site, and when an enzyme is "working hardest" ? I mean, this is when the reaction occours faster (if [S] is high) and slower when [S] is low...

Is the graph showing the rate (=speed?) of reaction in ONE enzyme, or in all the enzymes converting substrate to produckt?


Image

thank you!

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MrMistery
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Post by MrMistery » Sun May 30, 2010 4:36 pm

the graph is showing the reaction rate in your test system. there is definitely more than one enzyme molecule there.

at Vmax virtually all enzymes are occupied with substrate molecules. As soon as one molecule of substrate dissociates, another one binds
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JackBean
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Post by JackBean » Wed Jun 02, 2010 10:12 am

as MrMistery said, the speed is of all enzyme present in the system (well, theoretically, you could probably express it as speed of one enzyme molecule).

However, Vmax or Vlim is relevant only to the high S concentrations! When [S] is low, you have nothing to do with Vlim.
Also, you should actually never reach Vlim, that's why is it V limiting ;)
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