Each enzyme works fastest at a particular pH because a change in pH
Correct answer: A. alters the charges on the side chains, changing the shape of the active site
- A. alters the charges on the side chains, changing the shape of the active site
- B. changes the molar mass of the enzyme
- C. removes the substrate from the solution
- D. converts the enzyme into a carbohydrate
Explanation
Excess hydrogen or hydroxide ions interfere with the ionic and hydrogen bonds between side chains, distorting the active site so the substrate no longer fits, and a large shift denatures the enzyme entirely. This is why pepsin works at about pH 2 in the stomach while trypsin needs about pH 8 in the small intestine. Small deviations are reversible, large ones are not.
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About Enzymes as Biocatalysts
Enzymes are protein or RNA biocatalysts that lower activation energy without being consumed, and their active sites bind specific substrates. The topic covers the lock and key and induced fit models, effects of temperature, pH and substrate concentration, cofactors, enzyme specificity, and competitive versus non-competitive inhibition.
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