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Denaturing Enzymes

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Denaturing Enzymes

Postby Edher » Mon Feb 14, 2005 1:13 am

Saludos,

Do human enzymes denature when the pH is too low or too high from their habitual pH range? If they don't, then what happens to them?

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Postby Edher » Mon Feb 14, 2005 1:20 am

I just figured out that the answer to my question is "yes." An enviromnment that's too acidic or too basic relative to that of the enzyme's habitual environment WILL denature the enzyme.

However, how exactly does it denature the enzyme in this case?

I know that if too much thermal energy is absorbed by the enzyme it denatures it because the molecules become very agitated and the bonds break.

I know that when it comes to difference in pH level it has to do something with hydrogen bonding, but that's all I can come up with right now.

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Postby thank.darwin » Mon Feb 14, 2005 4:57 pm

A enzyme will denature if the pH level is too low or too high - the bonds in the enzyme break and the enzyme loses its shape and it can no longer do its task - enzymes have specific shapes to alow specific substrates in and if it loses its shape it can no longer accept a subtrate and produce products. Enzymes are moswt often proteins and proteins are held together by hydrogen bonds and desulfide bridges and they are bonds that can be easy to break. Does that help? If you have any more questions then ask away!
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Postby sq » Thu Feb 17, 2005 5:02 am

an enzyme will also become denatured in temperatures that are above or below optimum, that is why in some cases high fevers are a concern if held for several days, denatured enzymes do have the ability to repair themselves once optimum conditions are met again.
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Postby Edher » Fri Feb 18, 2005 4:36 am

sq wrote:an enzyme will also become denatured in temperatures that are above or below optimum, that is why in some cases high fevers are a concern if held for several days, denatured enzymes do have the ability to repair themselves once optimum conditions are met again.


Saludos sd,

You're half right. An enzyme WILL denature if the temperature is too high. However, the enzyme WILL NOT denature if the temperature is too low. The reason why an enzyme denatures in hot environments is because it increases the kinetic energy of the atoms that make up the amino acids of the enzyme and eventually, the bonds start breaking. However, that doesn't occur when temperatures drop. The reactions are executed slowly because the molecules don't posses that much kinetic energy, therefore they move slowly. This is why the rate of subtstrates to reactant decreases.

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Postby Edher » Fri Feb 18, 2005 4:40 am

sq wrote:an enzyme will also become denatured in temperatures that are above or below optimum, that is why in some cases high fevers are a concern if held for several days, denatured enzymes do have the ability to repair themselves once optimum conditions are met again.


Furthermore, the enzymes don't denature immediatly after they go beyond the optimal level. They begin to denature gradually as the temperature increases.

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Postby thank.darwin » Fri Feb 18, 2005 8:54 pm

sq wrote:an enzyme will also become denatured in temperatures that are above or below optimum


You must mean pH levels - When pH levels get too low or too high an enzyme can become denatured.
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Postby annie » Mon Jan 02, 2006 11:35 am

i don't think 'Edher' meant pH levels. As an enzyme can also become denatured if the TEMPERATURE is too high. I know this as I am studying denaturing in a peice of coursework for my GCSE work in Biology at school! :)
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Postby bearhug » Thu Jan 05, 2006 10:36 pm

If you ever do a PCR you will learn a good amount on denaturing enzymes. pH and high temperature are the easiest ways to denature. Certain enzymes have certain limits to when they denature.
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yeah but...

Postby helpneeded » Tue Mar 20, 2007 12:28 am

but are their any treatments that are designed to demonstrate how easily enzymes are denatured?
im curious....
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Postby victor » Wed Mar 21, 2007 8:33 am

Edher wrote:I just figured out that the answer to my question is "yes." An enviromnment that's too acidic or too basic relative to that of the enzyme's habitual environment WILL denature the enzyme.

However, how exactly does it denature the enzyme in this case?


Edher


What I know is that too acidic environment means that there's too much hydrogen ion surrounds the enzyme. We know that mostly enzymes portions are proteins, which is composed of amino acids. When we see the enzyme's 3D structure, we know that this structure is built by non-covalent bonds which one of them is dipole interaction. So, if there's too much H+, it would interupt this interaction by binding to a negatively or slightly negative charged amino acid sidechain, eg. histidine, aspartate, glutamate. In other word, I think I'll consider it as fully protonated.
DIsruption in 3D structure of enzyme would denature it, because the conformation state to be a functional enzyme has gone :)
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Postby Dustfinger » Wed Mar 21, 2007 8:27 pm

For a PCR you cannot usa mammal enzymes because they denaturate at these temperatures. Youu hav to use special bacteria enzymes, for exampe from Thermus aquaticus(Taq) who live in hot springs.
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