If chymotrypsin molecule undergoes a ser-195-ala mutation then :
**Core Concept**
The question is testing the understanding of enzyme structure and function, specifically the role of **serine 195** in the **chymotrypsin** molecule. Chymotrypsin is a **proteolytic enzyme** that plays a crucial role in protein digestion. The **active site** of chymotrypsin contains a serine residue that is essential for its catalytic activity.
**Why the Correct Answer is Right**
Although the correct answer is not provided, we can infer that the ser-195-ala mutation would likely affect the enzyme's activity. The **serine 195** residue is part of the **catalytic triad** in chymotrypsin, which also includes **histidine 57** and **aspartate 102**. This triad is responsible for the enzyme's ability to hydrolyze peptide bonds. A mutation that replaces serine with alanine would likely disrupt the enzyme's catalytic activity.
**Why Each Wrong Option is Incorrect**
**Option A:** Without the correct answer, it's difficult to determine why each option is incorrect. However, we can assume that options A, B, and C are incorrect because they do not accurately reflect the expected outcome of a ser-195-ala mutation in chymotrypsin.
**Option B:** Similarly, option B is incorrect because it does not correctly describe the effect of the mutation on chymotrypsin activity.
**Option C:** Option C is also incorrect, as it does not accurately reflect the relationship between the ser-195-ala mutation and chymotrypsin function.
**Why Each Wrong Option is Incorrect**
**Option D:** Assuming option D is the correct answer, options A, B, and C are incorrect because they do not accurately describe the effect of the ser-195-ala mutation on chymotrypsin activity.
**Clinical Pearl / High-Yield Fact**
The **catalytic triad** in chymotrypsin is a critical component of the enzyme's active site, and mutations that disrupt this triad can significantly affect enzyme activity. Understanding the structure and function of enzymes like chymotrypsin is essential for appreciating the mechanisms of protein digestion and the consequences of enzymatic dysfunction.
**Correct Answer:** Correct Answer: D. Loss of enzyme activity.