Question

Which of the following statements is incorrect?

• A. Enzymes are denatured at high temperature but in certain exceptional organisms they are effective even at 80-90 degree celsius
• B. Enzymes require optimum pH for maximal activity
• C. All enzymes are exclusively proteinaceous
• D. Enzymes are highly specific

Answer 1

The correct option is C All enzymes are exclusively proteinaceous

Generally, enzymes are proteinaceous in nature but certain enzymes such as ribozymes are exceptions to proteinaceous enzymes. They are made up of nucleic acids. Ribozymes are RNA molecules capable of catalysing a biochemical reaction.
Enzymes are the catalysts in the living system. Being proteinaceous, the enzymes are generally thermolabile (temperature-sensitive) in nature. They generally work over a narrow range of temperature, usually corresponding to the body temperature of the organism. However, certain enzymes that are isolated from organisms who normally live under extremely high temperatures (up to 80-90 degree celsius) are stable and retain their catalytic power even at high temperatures.


Each enzyme has a characteristic optimum pH at which its activity is maximal. A deviation or change to more alkaline or acidic pH can cause a drop in the activity of enzymes. Most enzymes have an optimum pH in a range of 4-9.
Enzymes are highly specific in nature. It binds to a particular substrate as it fits into its active site. It means that an enzyme that catalyses one reaction may not catalyse another.