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Title: Catalase activity depending on hydrogen peroxide solution concentration. Post by: Kurmis on Apr 11, 2012 Hi,
As far as I understand, the higher the concentration of a substrate ( H2O2 in this case) the bigger the enzyme activity. The thing is, when I put various concentrations of a H2O2 solution (highest being 15% solution) on banana samples and then measured the pressure which was created by the resulting oxygen, it was other way round. The banana samples with the H2O2 were in syringes of the same volume. I expected that the sample with the 15% solution would result in comparetively bigger enzyme activity and therefore more O2 expelled, and more pressure being created. Yet it turned out that the highest pressure was reached by a 6% H2O2 solution sample. I'm at a loss here. Perhaps I needed to give the samples more time? I took the measurements for 3 minutes, perhaps not enough? Or have I misunderstood something? Title: Re: Catalase activity depending on hydrogen peroxide solution concentration. Post by: bio_man on Apr 11, 2012 How many measurements for each experiment (concentration level) did you take? You should take at least 3 to 5 for each.
Title: Re: Catalase activity depending on hydrogen peroxide solution concentration. Post by: Kurmis on Apr 12, 2012 There were time constraints, so with each concentration I only measured once. I know it is not good. I usually make five.
I've attached a graph representing the pressure over time. The red graph is with the 15% solution, the yellow with the 7,5% and the purple with the 6%. Other concentrations were used too, I just took them off from this graph not to make the picture too complicated. The thing is that all of the solutions made were dilutions of the 15% solution, yet all of their graphs are higher than the 15% one. Maybe I messed up the 15% mesurement somehow, but still, then the rest of the graphs should be positioned accordingly. |