Enzyme Question (fwd)

Stacy Ferguson sef at med.unc.edu
Fri Oct 27 05:58:19 EST 1995

In article <Pine.BSD.3.91.951024161554.20353A-100000 at astro.ocis.temple.edu>,
Joshua Park  <park at astro.ocis.temple.edu> wrote:
>I'm a ninth grader and I would appreciate some help.

You know, one thing you should have learned by high school is how to
do your own work. The questions you ask are not exactly telling us that
you have an interest in enzymes, but that you have a homework ossignment
or lab report due and either cut the lab or want to fudge the results you
got if you got the wrong ones. 
>This test would involve Hydrogen Peroxide.
>1. If we put in a 'pea-sized' amount of liver, potato, chicken, and apple, 
>to their respective test tubes, how 'fast' would their reactions be?
>Assigning a numerical value from 0-5 with 5 being the fastest, how would 
>one assign a number?
>Liver 4
>Potato X
>Chicken Y

You know what this sounds like to me? This sounds like a nice cheap experiment
that most public school systems can afford to buy supplies for to teach their
students about enzymes and how they function. Believe it or not, this
isn't the sort of question that the majority of us could answer because 
knowing the activities of every enzyme in everything in every food in our
own refrigerators isn't something most biologists do in our spare time. EIther
you should be able to find this answer in your text book (it wouldn't be in
many, although it's possible that peroxidase was given as an example of any
enzyme in your particular book) or you should have done this in the lab. No
teacher wouldn't have asked you a question like this unless the answer could 
be easily found by YOU. 

>2. At what temperature do enzymes catalyze most efficiently?
>37 C?
>Using the same numerical system, how would one assign the rate of enzyme 
>activity in:
>a) O degrees Centigrade
>b) 22 (room temperature)
>c) 37 (Body temp.)
>d) 100 (Boiling)

Again, don't you have access to a freezer (ice) and a stove/bunsen
burner/microwave/anything that can be used to boil water? This is
information you should be able to find out VERY easily. After all,
you're in a room right now, so you can handle the room temperature
thing too.

>3. At what pH do enzyme work the most efficiently?
>a) 3
>b) 10
>c) 7

Well, maybe you should do the experiment. Guess what? Even similar enzymes
can function differently at different pH's. For example, intestinal alkaline
phosphatase functions under basic conditions, as the name suggests. In fact,
I use it at VERY close to pH 10, one of your choices. The there's potato 
acid phosphatase, which functions at the other side of the pH scale. Both 
can function to remove phosphates from molecules, yet they have different
pH optima. If you can't answer the question, what makes you think that we
happen to know about the pH optima of enzymes in the foods you listed? 

>Also, using the same numerical system, how would one assign the values for 
>the rate of enzyme activity in the respective pH?

By doing the experiment. We aren't going to go food shopping, buy a bottle
of hydrogen peroxide and do the experiment for you. Either your teacher
expects you to do that yourself or he/she supplied them on your lab day,
which you either cut or went to, but want to change your answers if your
experiment got screwed up.

This isn't a forum for having others do your assignments for you. Go do 
the experiment and if there's a problem, then feel free to come back and
ask for help with figuring out what went wrong if it doesn't work the way 
it should. If the experiment doesn't work the way that it should, then
just hand in the answers you GOT. After all, do you think that every 
experiment that a biologist does works the first time? We have to deal with
that by repeating it until we've gotten it right. Since you are in high school
and won't be able to do that, handing in the answers that you did get is 
what you should be doing. 

Stacy Ferguson
sef at med.unc.edu

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