Data interpretationAlthough it is p

Data interpretation
Although it is possible that the water used in the reactions is contaminated with chemicals that
act directly on TMB (this
has
happened), it is most likely that the reactions do, indeed, depend
on peroxidase and TMB. We expect that tubes 3 and 4 will show no reactions.
For the tubes 1 and 2, however, it is important to complete the data analysis. An individual
reaction, of course, shows you how fast the enzyme produces its product for the particular
conditions inside that tube. To compare different tubes, you need to compare the
rates
of the
reactions. Therefore, you need to calculate the rate of each reaction. The “rate” is most easily
expressed as the “change in absorbance at 655 nm” (or
∆
A
655
) per minute. You could estimate
this by dividing the A
655
of several of your data points by the number of minutes that had
elapsed since adding the H
2
O
2
to that tube. (i.e., divide your 1-minute reading by 1 and your
two-minute reading by 2, then take the average). A more accurate way is to use all the data
points for each assay to calculate the best-fit line by linear regression, and determine the slope of
the line (which will be the
∆
A
655
/min.).