Problem 114 - Chemistry: The Central Science

Question

One of the many remarkable enzymes in the human body is carbonic anhydrase, which catalyzes the interconversion of carbon dioxide and water with bicarbonate ion and protons. If it were not for this enzyme, the body could not rid itself rapidly enough of the \(\mathrm{CO}_{2}\) accumulated by cell metabolism. The enzyme catalyzes the dehydration (release to air) of up to \(10^{7} \mathrm{CO}_{2}\) molecules per second. Which components of this description correspond to the terms enzyme, substrate, and turnover number?

Step-by-Step Solution

Answer

In the given description, the enzyme is "carbonic anhydrase", which acts on substrates carbon dioxide (CO₂) and water (H₂O) to produce bicarbonate ion (HCO₃⁻) and protons (H⁺). The turnover number is the number of CO₂ molecules processed per second, which is \(10^7\).

Step 1: Identify the enzyme

In the given description, the enzyme is mentioned as "carbonic anhydrase." It catalyzes the interconversion of carbon dioxide and water with bicarbonate ion and protons.

Step 2: Identify the substrates

The substrates in the given description are the molecules that the enzyme carbonic anhydrase acts upon. In this case, carbon dioxide (CO₂) and water (H₂O) are the substrates, which are converted to bicarbonate ion (HCO₃⁻) and protons (H⁺) in the presence of carbonic anhydrase.

Step 3: Identify the turnover number

The turnover number is stated in the description as the number of CO₂ molecules processed per second by the carbonic anhydrase enzyme. It is given that the enzyme catalyzes the dehydration of up to \(10^7\) CO₂ molecules per second. Therefore, the turnover number is \(10^7\).