Enzymes and pH
my question is what is the effect of ph on
enymes. according to the ph meter scale:ph10 bleach, ph7 sodium
phosphate, ph6 tap water and ph3 lemon juice, which of these have a zero
effect on enzymes?
I'm doing a lab class that i missed as a result cant answer the question
The question is: Which enzymes? Most human enzymes work at a optimal pH
of 7.4, but other enzymes work at many different pH ranges.
It depends on what the enzyme is. The condition that most closely mirrors
the environment that the enzyme was designed for will have "zero effect".
Donald Yee Ph.D.
Instead of answering this question for you, I am going to help you along the
way with your though process. I prefer to address this question in this
manner because science is full of similar problems. What you need to consider
is the natural functional / biological environment of your enzyme. That is,
there are two major components to consider in this question, the pH at which
enzymes function and the ionic contents of your solution. Any changes to that
standard system are going to effect your enzyme's function.
Each enyzme has it's own pH optimum. Some can do their
work in a broad range of pHs, others are very
sensitive and only work at the exactly right pH. Most
enzymes work best in or around neutral pH, say between
pH 7 and 8. However, some enzymes are needed in
conditions of extreme pH, and use that pH as an
optimum for activity. For instance, pepsin that is
needed in the stomach has an acidic optimum and would
work in lemon juice. Other enzymes work best in
alkaline conditions. A solution with a buffered pH
(like sodium phosphate) will be better for enzymatic
activity than a non-buffered solution (tap water)
because enzymes are proteins, and these can themselves
influence the pH of the solution if this is not
buffered. Stangely enough, an enzyme that would turn
water acidic may have an optimum at alkaline pH. So,
in conclusion, each enzyme has it's own pH optimum.
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Update: June 2012