Biology Forum › Cell Biology › enzyme activity, please help
November 16, 2010 at 8:51 pm #14135Fa23Participant
can an enzyme have a negative activity? i had to do this lab and the values i got produce a negative value for activity. so i will just list here a few values that give a negative activity
Optical Density at 0 time, OD after 60s
to find activity you do the following:
(OD at 0 time – OD after 60s)/0.001
but doing this yields a negative value for the enzyme activity, is that okay?
November 16, 2010 at 8:57 pm #102302canalonParticipantquote Fa23:(OD at 0 time – OD after 60s)/0.001
Here is your mistake.
I assume that your enzyme activity cause an increase of OD so if you want to measure how much the OD has increased you sure got it the wrong way…
November 17, 2010 at 12:06 pm #102318Fa23Participantquote :got it the wrong way…
so just flip it around…thats fine and all for this set but the rest of the values are not increasing, either they are steady or they are actually lower than O.D at time 0
November 17, 2010 at 12:10 pm #102319DeatParticipant
Maybe there was human error when collecting the results, in any case, completley restart your equations and keep a log of your equations so that you can quickly identify the error. This would be the best way as it would help prevent future errors.
November 18, 2010 at 6:50 am #102332JackBeanParticipant
actually, the absorbance could decrease as well, if the color substance was consumed 😉 For example the cytkinin oxidase/dehydrogenase may be measured by decoloration of electron acceptor DCPIP 😉
September 16, 2011 at 7:28 am #106364TrevorwinParticipant
Hello!! and how can enzyme inhibitors irreversibly inactivate enzymes??
September 16, 2011 at 10:12 am #106366JackBeanParticipant
by denaturation, binding to crucial residues etc.
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