Enzymes activity decreases at very low or high pH because:
- A. Substrate concentration increases
- B. Enzymes become denatured
- C. Product formation increases
- D. Temperature becomes constant
Explanation
Excess hydrogen or hydroxide ions disturb the ionic and hydrogen bonds between the side chains that hold the tertiary structure, so the active site loses its precise shape and the substrate no longer fits. A small shift is reversible, but an extreme one denatures the enzyme permanently. This is why pepsin works at about pH 2 and trypsin at about pH 8, each being inactive in the other's conditions.
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