legallyblind
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Now I've been taught why enzymes DON'T work well at certain pHs (they get denatured) but not why enzymes DO work best at certain pHs. What does the optimum pH do in particular to get the enzyme to work best? (I do IB HL Biology, btw). I'm trying to write a lab report on my experiment, and I can't progress without understanding this Help, someone?
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sportyegg
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The reasoning for why enzymes have optimum pH levels to work at follows the exact same rationale for why they denature at certain pHs; so, an enzyme like pepsin works best in acidic conditions like in the stomach, whilst an enzyme like maltase works best in alkaline conditions such as the small intestine. Due to this the hydrogen bonds that hold together the polypeptide chains in the tertiary structure will not break, thus the chains will not unravel and the active site will not change shape.
Hopefully this helps - if you want any further clarification don’t hesitate to ask me.
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legallyblind
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(Original post by sportyegg)
The reasoning for why enzymes have optimum pH levels to work at follows the exact same rationale for why they denature at certain pHs; so, an enzyme like pepsin works best in acidic conditions like in the stomach, whilst an enzyme like maltase works best in alkaline conditions such as the small intestine. Due to this the hydrogen bonds that hold together the polypeptide chains in the tertiary structure will not break, thus the chains will not unravel and the active site will not change shape.
Hopefully this helps - if you want any further clarification don’t hesitate to ask me.
So it's more of the case of the optimum pH being the only pH where it WON'T start to denature, as opposed to it having a special effect like an optimum temperature would on the kinetic energy and therefore enzyme activity?
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sportyegg
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(Original post by Victoria Soh)
So it's more of the case of the optimum pH being the only pH where it WON'T start to denature, as opposed to it having a special effect like an optimum temperature would on the kinetic energy and therefore enzyme activity?
Yup exactly! pH doesn’t affect enzymes in the same way temperature does, thus the only thing that allows for it to be optimum is the fact that it won’t change the polypeptide structure of enzymes.
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legallyblind
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(Original post by sportyegg)
Yup exactly! pH doesn’t affect enzymes in the same way temperature does, thus the only thing that allows for it to be optimum is the fact that it won’t change the polypeptide structure of enzymes.
Ayyyy thank you so much you legend!!!!!!
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The A-level kid
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(Original post by Victoria Soh)
So it's more of the case of the optimum pH being the only pH where it WON'T start to denature, as opposed to it having a special effect like an optimum temperature would on the kinetic energy and therefore enzyme activity?
An optimum pH basically tells you when an enzyme works at its most BEST. E.g. Ph7 however that doesnt suddenly mean it will stop working if the ph changed to something like pH 8. It will still work, just not as efficiently. Enzymes work best over a RANGE of pH e.g. 5-9 The purpose of enzymes requiring an ideal pH is because enzymes will maintain their rigidity at their optimal pH, being the perfect fit for substrates molecules & thus enabling the enzyme-substrate complex. A good pH, ideal temperature ensure optimal activity enabling metabolic processes e.g. respiration to work efficiently. If any of these factors changes dramatically, the processes are less effective and thus effects the mechanisms.
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sportyegg
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(Original post by Victoria Soh)
Ayyyy thank you so much you legend!!!!!!
No worries!
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