In which of the following given examples, the value of Vmax changes while the K, value remains same?

Options

A. Inhibition of succinate dehydrogenase by malonate
B. Inhibition of alcohol dehydrogenase to treat methanol poisoning
C. Inhibition of cytochrome oxidase by cyanide
D. Inhibition of folic acid synthesis in bacteria by sulpha drugs

Answer

To solve the question of which example shows a change in Vmax while the K value remains the same, we can break down the information provided in the video transcript step by step.

### Step 1: Understand the Terms
- **Vmax**: The maximum rate of an enzyme-catalyzed reaction when the enzyme is saturated with substrate.
- **K (Michaelis constant)**: A measure of the affinity of the enzyme for its substrate; it is the substrate concentration at which the reaction rate is half of Vmax.

### Step 2: Types of Inhibition
There are two main types of enzyme inhibition:
1. **Competitive Inhibition**: The inhibitor competes with the substrate for the active site. In this case, Vmax remains the same, but the K value increases.
2. **Non-competitive Inhibition**: The inhibitor binds to an allosteric site, not the active site, which can change the Vmax while the K value remains the same.

### Step 3: Analyze the Given Examples
1. **Inhibition of succinate dehydrogenase by malonate**: This is competitive inhibition, so Vmax remains the same, and K value changes.
2. **Inhibition of alcohol dehydrogenase to treat methanol**: This is also competitive inhibition, so Vmax remains the same, and K value changes.
3. **Inhibition of cytochrome oxidase by cyanide**: This is non-competitive inhibition, which means Vmax changes while K remains the same.
4. **Inhibition of folic acid synthesis by N-bacteria by sulfa drugs**: This is competitive inhibition, so Vmax remains the same, and K value changes.

### Step 4: Conclusion
From the analysis, the example where Vmax changes while K remains the same is the **inhibition of cytochrome oxidase by cyanide**.

### Final Answer
The correct example is: **Inhibition of cytochrome oxidase by cyanide.**

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