Enzymes and pH

D

Dudeyhed

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Registered Senior Member
I feel like I'm a leech using the people on this board for info!!
I haven't really contributed much but I promise I will try to if I can :D

I need some information on enzymes and how they are affected by pH.

I just completed a prac on Enzymes and temperature and now we have to design a prac to, well, here's the question:

'In this exercise you tested the effects of temperature on enzyme activity. Design an alternatice procedure you could have used to test the effect of variation in pH on the enzyme's activity.'

So far I've found that enzymes in our body generally have an optimum reation rate when they are around 7 pH.

I would really appreciate any information anyone may have, or any sites or other resources that may be useful. :)
 
What about pepsinogen (into pepsin) and trypsinogen (trypsin) and the like that are turned on by the low pH of the stomach acid? Most enzymes in the body will operate at their optimum near or at the normal blood pH (I think it's like 7.2 or 7.4 IIRC), but some need extreme conditions to function at all.

pH, like temperature, can denature the proteins by disrupting the intramolecular bonds (which are a lot of H-bonds), so a pH shift that is too great can affect the shape, and therefore function of the enzymes.

Hope that helps a little.
 
I think that it could be helpful, but I don't quite understand what you've said.

Originally posted by Idle Mind
What about pepsinogen (into pepsin) and trypsinogen (trypsin) and the like that are turned on by the low pH of the stomach acid?
Click to expand...
I don't understand... what about them?

Most enzymes in the body will operate at their optimum near or at the normal blood pH (I think it's like 7.2 or 7.4 IIRC), but some need extreme conditions to function at all.
Click to expand...
What do you mean by extreme conditions?

Also something I should note.

I think that we are supposed to focus on the enzyme diastase as that was the enzyme we worked with during the prac with temperature.
 
Originally posted by Dudeyhed

'In this exercise you tested the effects of temperature on enzyme activity. Design an alternatice procedure you could have used to test the effect of variation in pH on the enzyme's activity.'
Click to expand...

do the same experiment over again you did the first time at optimal temperature, but now use different solutions with different Ph.
Measure the PH of the original solution. i don't know what kind of equipment you got there. But add some acid (a few drops of HCL for instance, depends a bit on the nature of the solution you are working with). Measure the Ph. It must be significant lower. Take more solution, add more acid...the PH is even lower. If you have a Base (NaOH for instance)...add that to the original solution... the PH is higher now.

in short:
you will have at least three solution. One with lower PH (added acid), the original solution, and a solution with higher PH (added base). Measure the activity difference between these solution. Put it in a graph...

is this what you meant?
 
Pepsin is a digestive enzyme in our stomach. To prevent this enzyme from breaking down our own tissues in the pancreas (I think that's where they are made), our body produces pepsinogen, a non-digestive pre-cursor. The acidic (this is what I meant by extreme, since the pH is so low compared to the rest of the body) environment in the stomach changes the pepsinogen into pepsin, the active enzyme. Same with trypsinogen, which needs contact with bile (which is basic I think) or something similar to change into trypsin.

For the actual procedure, I think spurious has it pretty much set up.

Diastase breaks down glycogen right? So it is likely in high concentrations in the liver and skeletal muscle tissues where glycogen is stored. What do you think the conditions are like in the liver and muscle tissue, in terms of pH?
 
Originally posted by Idle Mind
Pepsin is a digestive enzyme in our stomach. To prevent this enzyme from breaking down our own tissues in the pancreas (I think that's where they are made), our body produces pepsinogen, a non-digestive pre-cursor. The acidic (this is what I meant by extreme, since the pH is so low compared to the rest of the body) environment in the stomach changes the pepsinogen into pepsin, the active enzyme. Same with trypsinogen, which needs contact with bile (which is basic I think) or something similar to change into trypsin.

For the actual procedure, I think spurious has it pretty much set up.

Diastase breaks down glycogen right? So it is likely in high concentrations in the liver and skeletal muscle tissues where glycogen is stored. What do you think the conditions are like in the liver and muscle tissue, in terms of pH?
Click to expand...

eek!:eek:
I think that a lot of the stuff your saying is too advanced! We diddn't really need to go that deed, we diddn't even need to discuss the procedure, just write it out.

And I did end up doing what spuriousmonkey said, I stated 5 solutions, a strong/weak acid and base and distilled water and followed the same procedure as the temperature varying one.
Just got my mark today too :D

A :D

Thanks for your help:)
 
Dam it a perfect BioChem question and everyone answers it before me... I'll Kill you ALL!
 
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