An enzyme works well at as a catalyst at a pH of 7.2.It is found that catalytic activity is significantly less at a pH of 8.4.Which could likely cause the decrease in activity?
A)The protein has been degraded into its amino acids at pH 8.4.
B)The protein has changed shape due to a change in charge.
C)The protonation state of amino acids involved in the catalytic mechanism has changed.
D)B and C above.
E)All of the above.

Question

Quizplus · Accepted Answer

Option B is correct as the change in pH can affect the charge of the amino acid residues in the active site of the enzyme, which can change the shape of the protein and thus affect its catalytic activity. Option C is also correct since the catalytic activity of enzymes can be affected by the protonation state of amino acid residues in the active site. Option A is not correct because the degradation of the protein would result in a loss of protein structure and function, not just a change in catalytic activity. Option E is incorrect as it includes option A, which is not a likely cause of the decrease in activity. Therefore, the best answer is D.

An Enzyme Works Well at as a Catalyst at a PH