Amylase--Michealis-Menten kinetics?

[K N and P J Harris]

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> bionet/microbiology #944, from brucerat at aol.com, 961 chars, 20 Oct 
1995 09:21:50 -0
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> Article: 1895 of bionet.microbiology
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> From: brucerat at aol.com (BruceRat)
> Newsgroups: bionet.microbiology
> Subject: Amylase--Michealis-Menten kinetics?
> Date: 20 Oct 1995 09:21:50 -0400
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> Using a simple photometer to detect digestion of iodine-stained 
arrowroot
> starch by salivary amylase, I have gotten a graph that is FAIRLY 
closely
> modeled by the  Michaelis-Menten equation.  But it deviates 
significantly.
>  Do you have any suggestions as to why?  
> Bruce Ratcliffe, AP Bio teacher, Edison High School Fresno, CA  
> BruceRat at AOL.COM
If the iodine is added too early or too strongly it will interfere with 
the enzymic activity. The same mess-up happens with most iodometric 
titrations if the iodine is added too soon.
Peter Harris,
Univerisity of Reading, UK.