[asd123]

Hello. Im new here.
I am currently doing on a project and my result show enzyme activity increase and decrease over a period of time and I not sure why. The enzyme involved are Alpha-amylase, Protease and Cellulase and all are enzyme found in feed and those enzyme are made from bacteria.

My experiment need to find enzyme stability/activity for animal feed, all the pH,substrate concentration are kept constant, which just the temperature different which each feed are stored in 3 different temperature, 25, 30 and 40 degree Celsius.

These are the graph of my results

Alpha-amylase
http://img149.imageshack.us/my.php?image=alphaamylase2jt.png

Protease
http://img149.imageshack.us/my.php?image=protease5gn.png

Cellulase
http://img149.imageshack.us/my.php?image=cellulase9zd.png

I already search for answers for the results but to no avail to why the enzyme activity is increasing and decreasing and increasing as the results are supposed to show decreasing of enzyme activity.

Thanks for the help.

[Yggdrasil]

For a lot of the activity curves, although they appear to be increasing, you can't really say they are because of the error bars of the measurements (for example, the blue and orange lines in the alpha-amylase graph).  But there clearly are some enzymes whose activity apparently increases.  Here are some troubleshooting questions:

Were all of the enzyme assays performed at the same temperature?  Was enough time/a consistent time given to allow the 40^o and the samples to equilibrate to the assay temperature?

How did you assay the activities of these enzymes?  Were the substrates made fresh the day of the assay?  Could the spontaneous degradation of your substrates account for the apparent increase in activity?

Some proteases are zymogens (http://en.wikipedia.org/wiki/Zymogen), and the activities of these enzymes would be expected to increase over time (though I'm not sure you'd see the increases you are seeing).  Is your bacterial protease a zymogen?

Are you sure that there is a consistent amount of enzyme assayed at every time point?  If the amounts of enzyme vary in each sample/preparation, then you should probably look at specific activity (units/mg) and not just activity.

[ahpeasant]

hah ....if you finish the determination of the acttivty of the enzyme under the same condition, i believe you can not get the incease of the activity of enzyme