Enzyme action

[Smiley_]

what is a parameter that effects enzyme activity that would need to be controlled in an experiment that tests the effect of amylase ?

[aishuwa1995]

ph, temperature and the concentration of substrate or enzyme are things that affect enzyme activity. You will need to keep all factors constant except the one you are testing. For example, if you're testing how amylase is affected by ph, you will need to keep the temperature and the concentration of substrate and enzyme constant. 

[Smiley_]

ph, temperature and the concentration of substrate or enzyme are things that affect enzyme activity. You will need to keep all factors constant except the one you are testing. For example, if you're testing how amylase is affected by ph, you will need to keep the temperature and the concentration of substrate and enzyme constant. 

thanks also
we stopped the reaction by adding HCl by would this stop the reaction?

[aishuwa1995]

amylase works well in a neutral-basic environment (in the mouth..) Amylase gets denatured in low pH because the concentration of H⁺ ions increase and messes with the enzyme's 3D shape by disrupting the bonds between amino acids. I don't think you need to know that much detail but that's how it works I think.

[Yacoubb]

By adding HCl, you're denaturing the enzyme as the lower pH is beyond the optimum pH of amylase and so the active site is distorted by damage to hydrogen and ionic bonds. Enzyme activity is stopped because enzymes active sites can no longer attach to substrate and catalyse the breakdown of starch/polysaccharides.

[psyxwar]

By adding HCl, you're denaturing the enzyme as the lower pH is beyond the optimum pH of amylase and so the active site is distorted by damage to hydrogen and ionic bonds. Enzyme activity is stopped because enzymes active sites can no longer attach to substrate and catalyse the breakdown of starch/polysaccharides.

That's a bad way to word it -- it's not denaturing it just because it's outside the optimal pH, it's because it's at a pH extremity (which in the case of amylase would denature it because its optimal pH at around 7ish). The optimal temperature is the point where the enzyme functions best -- the enzyme can be outside of it without denaturing.

[Yacoubb]

That's a bad way to word it -- it's not denaturing it just because it's outside the optimal pH, it's because it's at a pH extremity (which in the case of amylase would denature it because its optimal pH at around 7ish). The optimal temperature is the point where the enzyme functions best -- the enzyme can be outside of it without denaturing.

Yes but a low pH will be acidic, right? And so by having the protein exposed to a low pH (acidic) HCl, the active site of the enzyme will become affected due to the breaking of bonds between R-varibable groups. Just one quick clarification - do we only say denatured when the pH or temperature becomes > the optimum temperature of pH? Because if thats the case then  think your answer makes sense.

[Bad Student]

Yes but a low pH will be acidic, right? And so by having the protein exposed to a low pH (acidic) HCl, the active site of the enzyme will become affected due to the breaking of bonds between R-varibable groups. Just one quick clarification - do we only say denatured when the pH or temperature becomes > the optimum temperature of pH? Because if thats the case then  think your answer makes sense.

When the temperature becomes too high, enzymes are denatured. A low temperature doesn't cause denaturation.

A pH which is too low or too high can cause denaturation.

[Yacoubb]

When the temperature becomes too high, enzymes are denatured. A low temperature doesn't cause denaturation.

A pH which is too low or too high can cause denaturation.

Yeah so then by adding HCl to the enzyme, the active site would be damaged and distorted due to denaturation at a very acidic, low pH, exceeding the optimum pH of around 6-8, roughly. I think what psyxwar was trying to say was that my wording was weird - lower than the optimum is not sufficient in a way; the extremely low pH of HCl causes is to denature; The bell shaped curve is best to describe the relationship between ph (independent variable) and enzyme activity (dependent variable).

[psyxwar]

Yes but a low pH will be acidic, right? And so by having the protein exposed to a low pH (acidic) HCl, the active site of the enzyme will become affected due to the breaking of bonds between R-varibable groups. Just one quick clarification - do we only say denatured when the pH or temperature becomes > the optimum temperature of pH? Because if thats the case then  think your answer makes sense.

An enzyme has to be significantly outside the optimal pH to be denatured as far as I know. So just being outside the optimal isn't enough.